root/sys/dev/sound/usb/uaudio.c
/*      $NetBSD: uaudio.c,v 1.91 2004/11/05 17:46:14 kent Exp $ */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1999 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Lennart Augustsson (lennart@augustsson.net) at
 * Carlstedt Research & Technology.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
/*
 * USB audio specs: http://www.usb.org/developers/devclass_docs/audio10.pdf
 *                  http://www.usb.org/developers/devclass_docs/frmts10.pdf
 *                  http://www.usb.org/developers/devclass_docs/termt10.pdf
 */

/*
 * Also merged:
 *  $NetBSD: uaudio.c,v 1.94 2005/01/15 15:19:53 kent Exp $
 *  $NetBSD: uaudio.c,v 1.95 2005/01/16 06:02:19 dsainty Exp $
 *  $NetBSD: uaudio.c,v 1.96 2005/01/16 12:46:00 kent Exp $
 *  $NetBSD: uaudio.c,v 1.97 2005/02/24 08:19:38 martin Exp $
 */

#include <sys/stdint.h>
#include <sys/stddef.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
#include <sys/unistd.h>
#include <sys/callout.h>
#include <sys/malloc.h>
#include <sys/priv.h>

#include <dev/hid/hid.h>

#include "usbdevs.h"
#include <dev/usb/usb.h>
#include <dev/usb/usbdi.h>
#include <dev/usb/usbdi_util.h>
#include <dev/usb/usbhid.h>
#include <dev/usb/usb_request.h>
#include <dev/usb/usb_process.h>

#define USB_DEBUG_VAR uaudio_debug
#include <dev/usb/usb_debug.h>

#include <dev/usb/quirk/usb_quirk.h>

#include <sys/reboot.h>                 /* for bootverbose */

#ifdef HAVE_KERNEL_OPTION_HEADERS
#include "opt_snd.h"
#endif

#include <dev/sound/pcm/sound.h>
#include <dev/sound/usb/uaudioreg.h>
#include <dev/sound/usb/uaudio.h>
#include "feeder_if.h"

static int uaudio_default_rate = 0;             /* use rate list */
static int uaudio_default_bits = 0;             /* use default sample size */
static int uaudio_default_channels = 0;         /* use default */
static int uaudio_buffer_ms = 4;
static bool uaudio_handle_hid = true;

static SYSCTL_NODE(_hw_usb, OID_AUTO, uaudio, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "USB uaudio");
SYSCTL_BOOL(_hw_usb_uaudio, OID_AUTO, handle_hid, CTLFLAG_RWTUN,
    &uaudio_handle_hid, 0, "uaudio handles any HID volume/mute keys, if set");
SYSCTL_INT(_hw_usb_uaudio, OID_AUTO, default_rate, CTLFLAG_RWTUN,
    &uaudio_default_rate, 0, "uaudio default sample rate");
SYSCTL_INT(_hw_usb_uaudio, OID_AUTO, default_bits, CTLFLAG_RWTUN,
    &uaudio_default_bits, 0, "uaudio default sample bits");
SYSCTL_INT(_hw_usb_uaudio, OID_AUTO, default_channels, CTLFLAG_RWTUN,
    &uaudio_default_channels, 0, "uaudio default sample channels");

#define UAUDIO_BUFFER_MS_MIN    1
#define UAUDIO_BUFFER_MS_MAX    8

static int
uaudio_buffer_ms_sysctl(SYSCTL_HANDLER_ARGS)
{
        int err, val;

        val = uaudio_buffer_ms;
        err = sysctl_handle_int(oidp, &val, 0, req);

        if (err != 0 || req->newptr == NULL || val == uaudio_buffer_ms)
                return (err);

        if (val > UAUDIO_BUFFER_MS_MAX)
                val = UAUDIO_BUFFER_MS_MAX;
        else if (val < UAUDIO_BUFFER_MS_MIN)
                val = UAUDIO_BUFFER_MS_MIN;

        uaudio_buffer_ms = val;

        return (0);
}
SYSCTL_PROC(_hw_usb_uaudio, OID_AUTO, buffer_ms,
    CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, 0, sizeof(int),
    uaudio_buffer_ms_sysctl, "I",
    "uaudio buffering delay in milliseconds, from 1 to 8");

#ifdef USB_DEBUG
static int uaudio_debug;

SYSCTL_INT(_hw_usb_uaudio, OID_AUTO, debug, CTLFLAG_RWTUN,
    &uaudio_debug, 0, "uaudio debug level");
#else
#define uaudio_debug 0
#endif

#define UAUDIO_NFRAMES          64      /* must be factor of 8 due HS-USB */
#define UAUDIO_NCHANBUFS        2       /* number of outstanding request */
#define UAUDIO_RECURSE_LIMIT    255     /* rounds */
#define UAUDIO_BITS_MAX         32      /* maximum sample size in bits */
#define UAUDIO_CHANNELS_MAX     min(64, AFMT_CHANNEL_MAX)
#define UAUDIO_MATRIX_MAX       8       /* channels */

#define MAKE_WORD(h,l) (((h) << 8) | (l))
#define BIT_TEST(bm,bno) (((bm)[(bno) / 8] >> (7 - ((bno) % 8))) & 1)
#define MIX(sc) ((sc)->sc_mixer_node)

union uaudio_asid {
        const struct usb_audio_streaming_interface_descriptor *v1;
        const struct usb_audio20_streaming_interface_descriptor *v2;
};

union uaudio_asf1d {
        const struct usb_audio_streaming_type1_descriptor *v1;
        const struct usb_audio20_streaming_type1_descriptor *v2;
};

union uaudio_sed {
        const struct usb_audio_streaming_endpoint_descriptor *v1;
        const struct usb_audio20_streaming_endpoint_descriptor *v2;
};

struct uaudio_mixer_node {
        const char *name;

        int32_t minval;
        int32_t maxval;
#define MIX_MAX_CHAN 16
        int32_t wValue[MIX_MAX_CHAN];   /* using nchan */
        uint32_t mul;
        uint32_t ctl;

        int wData[MIX_MAX_CHAN];        /* using nchan */
        uint16_t wIndex;

        uint8_t update[(MIX_MAX_CHAN + 7) / 8];
        uint8_t nchan;
        uint8_t type;
#define MIX_ON_OFF      1
#define MIX_SIGNED_16   2
#define MIX_UNSIGNED_16 3
#define MIX_SIGNED_8    4
#define MIX_SELECTOR    5
#define MIX_UNKNOWN     6
#define MIX_SIZE(n) ((((n) == MIX_SIGNED_16) || \
                      ((n) == MIX_UNSIGNED_16)) ? 2 : 1)
#define MIX_UNSIGNED(n) ((n) == MIX_UNSIGNED_16)

#define MAX_SELECTOR_INPUT_PIN 256
        uint8_t slctrtype[MAX_SELECTOR_INPUT_PIN];
        uint8_t val_default;

        uint8_t desc[64];

        struct uaudio_mixer_node *next;
};

struct uaudio_configure_msg {
        struct usb_proc_msg hdr;
        struct uaudio_softc *sc;
};

#define CHAN_MAX_ALT 24

struct uaudio_chan_alt {
        union uaudio_asf1d p_asf1d;
        union uaudio_sed p_sed;
        const usb_endpoint_descriptor_audio_t *p_ed1;
        const struct uaudio_format *p_fmt;
        const struct usb_config *usb_cfg;
        uint32_t sample_rate;   /* in Hz */
        uint16_t sample_size;
        uint8_t iface_index;
        uint8_t iface_alt_index;
        uint8_t channels;
};

struct uaudio_chan {
        struct pcmchan_caps pcm_cap;    /* capabilities */
        struct uaudio_chan_alt usb_alt[CHAN_MAX_ALT];
        struct snd_dbuf *pcm_buf;
        struct mtx lock;                /* lock protecting this structure */
        struct uaudio_softc *priv_sc;
        struct pcm_channel *pcm_ch;
        struct usb_xfer *xfer[UAUDIO_NCHANBUFS + 1];

        uint8_t *buf;                   /* pointer to buffer */
        uint8_t *start;                 /* upper layer buffer start */
        uint8_t *end;                   /* upper layer buffer end */
        uint8_t *cur;                   /* current position in upper layer
                                         * buffer */

        uint32_t intr_frames;           /* in units */
        uint32_t frames_per_second;
        uint32_t sample_rem;
        uint32_t sample_curr;
        uint32_t max_buf;
        int32_t jitter_rem;
        int32_t jitter_curr;

        int feedback_rate;

        uint32_t pcm_format[2];

        uint16_t bytes_per_frame[2];

        uint32_t intr_counter;
        uint32_t running;
        uint32_t num_alt;
        uint32_t cur_alt;
        uint32_t set_alt;
        uint32_t operation;
#define CHAN_OP_NONE 0
#define CHAN_OP_START 1
#define CHAN_OP_STOP 2
#define CHAN_OP_DRAIN 3

        uint8_t iface_index;
};

#define UMIDI_EMB_JACK_MAX   16         /* units */
#define UMIDI_TX_FRAMES    256          /* units */
#define UMIDI_TX_BUFFER    (UMIDI_TX_FRAMES * 4)        /* bytes */

enum {
        UMIDI_TX_TRANSFER,
        UMIDI_RX_TRANSFER,
        UMIDI_N_TRANSFER,
};

struct umidi_sub_chan {
        struct usb_fifo_sc fifo;
        uint8_t *temp_cmd;
        uint8_t temp_0[4];
        uint8_t temp_1[4];
        uint8_t state;
#define UMIDI_ST_UNKNOWN   0            /* scan for command */
#define UMIDI_ST_1PARAM    1
#define UMIDI_ST_2PARAM_1  2
#define UMIDI_ST_2PARAM_2  3
#define UMIDI_ST_SYSEX_0   4
#define UMIDI_ST_SYSEX_1   5
#define UMIDI_ST_SYSEX_2   6

        uint8_t read_open:1;
        uint8_t write_open:1;
        uint8_t unused:6;
};

struct umidi_chan {
        struct umidi_sub_chan sub[UMIDI_EMB_JACK_MAX];
        struct mtx mtx;

        struct usb_xfer *xfer[UMIDI_N_TRANSFER];

        uint8_t iface_index;
        uint8_t iface_alt_index;

        uint8_t read_open_refcount;
        uint8_t write_open_refcount;

        uint8_t curr_cable;
        uint8_t max_emb_jack;
        uint8_t valid;
        uint8_t single_command;
};

struct uaudio_search_result {
        uint8_t bit_input[(256 + 7) / 8];
        uint8_t bit_output[(256 + 7) / 8];
        uint8_t recurse_level;
        uint8_t id_max;
        uint8_t is_input;
};

enum {
        UAUDIO_HID_RX_TRANSFER,
        UAUDIO_HID_N_TRANSFER,
};

struct uaudio_hid {
        struct usb_xfer *xfer[UAUDIO_HID_N_TRANSFER];
        struct hid_location volume_up_loc;
        struct hid_location volume_down_loc;
        struct hid_location mute_loc;
        uint32_t flags;
#define UAUDIO_HID_VALID                0x0001
#define UAUDIO_HID_HAS_ID               0x0002
#define UAUDIO_HID_HAS_VOLUME_UP        0x0004
#define UAUDIO_HID_HAS_VOLUME_DOWN      0x0008
#define UAUDIO_HID_HAS_MUTE             0x0010
        uint8_t iface_index;
        uint8_t volume_up_id;
        uint8_t volume_down_id;
        uint8_t mute_id;
};

#define UAUDIO_SPDIF_OUT        0x01    /* Enable S/PDIF output */
#define UAUDIO_SPDIF_OUT_48K    0x02    /* Out sample rate = 48K */
#define UAUDIO_SPDIF_OUT_96K    0x04    /* Out sample rate = 96K */
#define UAUDIO_SPDIF_IN_MIX     0x10    /* Input mix enable */

#define UAUDIO_MAX_CHILD 2

struct uaudio_softc_child {
        device_t pcm_device;
        struct mtx *mixer_lock;
        struct snd_mixer *mixer_dev;

        uint32_t mix_info;
        uint32_t recsrc_info;

        uint8_t pcm_registered:1;
        uint8_t mixer_init:1;
};

struct uaudio_softc {
        struct uaudio_chan sc_rec_chan[UAUDIO_MAX_CHILD];
        struct uaudio_chan sc_play_chan[UAUDIO_MAX_CHILD];
        struct umidi_chan sc_midi_chan;
        struct uaudio_hid sc_hid;
        struct uaudio_search_result sc_mixer_clocks;
        struct uaudio_mixer_node sc_mixer_node;
        struct uaudio_configure_msg sc_config_msg[2];
        struct uaudio_softc_child sc_child[UAUDIO_MAX_CHILD];

        struct usb_device *sc_udev;
        struct usb_xfer *sc_mixer_xfer[1];
        struct uaudio_mixer_node *sc_mixer_root;
        struct uaudio_mixer_node *sc_mixer_curr;
        int     (*sc_set_spdif_fn) (struct uaudio_softc *, int);

        uint16_t sc_audio_rev;
        uint16_t sc_mixer_count;

        uint8_t sc_mixer_iface_index;
        uint8_t sc_mixer_iface_no;
        uint8_t sc_mixer_chan;
        uint8_t sc_uq_audio_swap_lr:1;
        uint8_t sc_uq_au_inp_async:1;
        uint8_t sc_uq_au_no_xu:1;
        uint8_t sc_uq_bad_adc:1;
        uint8_t sc_uq_au_vendor_class:1;
        uint8_t sc_pcm_bitperfect:1;
};

struct uaudio_terminal_node {
        union {
                const struct usb_descriptor *desc;
                const struct usb_audio_input_terminal *it_v1;
                const struct usb_audio_output_terminal *ot_v1;
                const struct usb_audio_mixer_unit_0 *mu_v1;
                const struct usb_audio_selector_unit *su_v1;
                const struct usb_audio_feature_unit *fu_v1;
                const struct usb_audio_processing_unit_0 *pu_v1;
                const struct usb_audio_extension_unit_0 *eu_v1;
                const struct usb_audio20_clock_source_unit *csrc_v2;
                const struct usb_audio20_clock_selector_unit_0 *csel_v2;
                const struct usb_audio20_clock_multiplier_unit *cmul_v2;
                const struct usb_audio20_input_terminal *it_v2;
                const struct usb_audio20_output_terminal *ot_v2;
                const struct usb_audio20_mixer_unit_0 *mu_v2;
                const struct usb_audio20_selector_unit *su_v2;
                const struct usb_audio20_feature_unit *fu_v2;
                const struct usb_audio20_sample_rate_unit *ru_v2;
                const struct usb_audio20_processing_unit_0 *pu_v2;
                const struct usb_audio20_extension_unit_0 *eu_v2;
                const struct usb_audio20_effect_unit *ef_v2;
        }       u;
        struct uaudio_search_result usr;
        struct uaudio_terminal_node *root;
};

struct uaudio_format {
        uint16_t wFormat;
        uint8_t bPrecision;
        uint32_t freebsd_fmt;
        const char *description;
};

static const struct uaudio_format uaudio10_formats[] = {
        {UA_FMT_PCM8, 8, AFMT_U8, "8-bit U-LE PCM"},
        {UA_FMT_PCM8, 16, AFMT_U16_LE, "16-bit U-LE PCM"},
        {UA_FMT_PCM8, 24, AFMT_U24_LE, "24-bit U-LE PCM"},
        {UA_FMT_PCM8, 32, AFMT_U32_LE, "32-bit U-LE PCM"},

        {UA_FMT_PCM, 8, AFMT_S8, "8-bit S-LE PCM"},
        {UA_FMT_PCM, 16, AFMT_S16_LE, "16-bit S-LE PCM"},
        {UA_FMT_PCM, 24, AFMT_S24_LE, "24-bit S-LE PCM"},
        {UA_FMT_PCM, 32, AFMT_S32_LE, "32-bit S-LE PCM"},

        {UA_FMT_ALAW, 8, AFMT_A_LAW, "8-bit A-Law"},
        {UA_FMT_MULAW, 8, AFMT_MU_LAW, "8-bit mu-Law"},
        {0, 0, 0, NULL}
};

static const struct uaudio_format uaudio20_formats[] = {
        {UA20_FMT_PCM, 8, AFMT_S8, "8-bit S-LE PCM"},
        {UA20_FMT_PCM, 16, AFMT_S16_LE, "16-bit S-LE PCM"},
        {UA20_FMT_PCM, 24, AFMT_S24_LE, "24-bit S-LE PCM"},
        {UA20_FMT_PCM, 32, AFMT_S32_LE, "32-bit S-LE PCM"},

        {UA20_FMT_PCM8, 8, AFMT_U8, "8-bit U-LE PCM"},
        {UA20_FMT_PCM8, 16, AFMT_U16_LE, "16-bit U-LE PCM"},
        {UA20_FMT_PCM8, 24, AFMT_U24_LE, "24-bit U-LE PCM"},
        {UA20_FMT_PCM8, 32, AFMT_U32_LE, "32-bit U-LE PCM"},

        {UA20_FMT_ALAW, 8, AFMT_A_LAW, "8-bit A-Law"},
        {UA20_FMT_MULAW, 8, AFMT_MU_LAW, "8-bit mu-Law"},
        {0, 0, 0, NULL}
};

/* prototypes */

static device_probe_t uaudio_probe;
static device_attach_t uaudio_attach;
static device_detach_t uaudio_detach;

static usb_callback_t uaudio_chan_play_callback;
static usb_callback_t uaudio_chan_play_sync_callback;
static usb_callback_t uaudio_chan_record_callback;
static usb_callback_t uaudio_chan_record_sync_callback;
static usb_callback_t uaudio_mixer_write_cfg_callback;
static usb_callback_t umidi_bulk_read_callback;
static usb_callback_t umidi_bulk_write_callback;
static usb_callback_t uaudio_hid_rx_callback;

static usb_proc_callback_t uaudio_configure_msg;

/* ==== USB mixer ==== */

static int uaudio_mixer_sysctl_handler(SYSCTL_HANDLER_ARGS);
static void uaudio_mixer_ctl_free(struct uaudio_softc *);
static void uaudio_mixer_register_sysctl(struct uaudio_softc *, device_t, unsigned);
static void uaudio_mixer_reload_all(struct uaudio_softc *);
static void uaudio_mixer_controls_create_ftu(struct uaudio_softc *);

/* ==== USB audio v1.0 ==== */

static void     uaudio_mixer_add_mixer(struct uaudio_softc *,
                    const struct uaudio_terminal_node *, int);
static void     uaudio_mixer_add_selector(struct uaudio_softc *,
                    const struct uaudio_terminal_node *, int);
static uint32_t uaudio_mixer_feature_get_bmaControls(
                    const struct usb_audio_feature_unit *, uint8_t);
static void     uaudio_mixer_add_feature(struct uaudio_softc *,
                    const struct uaudio_terminal_node *, int);
static void     uaudio_mixer_add_processing_updown(struct uaudio_softc *,
                    const struct uaudio_terminal_node *, int);
static void     uaudio_mixer_add_processing(struct uaudio_softc *,
                    const struct uaudio_terminal_node *, int);
static void     uaudio_mixer_add_extension(struct uaudio_softc *,
                    const struct uaudio_terminal_node *, int);
static struct   usb_audio_cluster uaudio_mixer_get_cluster(uint8_t,
                    const struct uaudio_terminal_node *);
static uint16_t uaudio_mixer_determine_class(const struct uaudio_terminal_node *);
static void     uaudio_mixer_find_inputs_sub(struct uaudio_terminal_node *,
                    const uint8_t *, uint8_t, struct uaudio_search_result *);
static const void *uaudio_mixer_verify_desc(const void *, uint32_t);
static usb_error_t uaudio_set_speed(struct usb_device *, uint8_t, uint32_t);
static int      uaudio_mixer_get(struct usb_device *, uint16_t, uint8_t,
                    struct uaudio_mixer_node *);

/* ==== USB audio v2.0 ==== */

static void     uaudio20_mixer_add_mixer(struct uaudio_softc *,
                    const struct uaudio_terminal_node *, int);
static void     uaudio20_mixer_add_selector(struct uaudio_softc *,
                    const struct uaudio_terminal_node *, int);
static void     uaudio20_mixer_add_feature(struct uaudio_softc *,
                    const struct uaudio_terminal_node *, int);
static struct   usb_audio20_cluster uaudio20_mixer_get_cluster(uint8_t,
                    const struct uaudio_terminal_node *);
static uint16_t uaudio20_mixer_determine_class(const struct uaudio_terminal_node *);
static void     uaudio20_mixer_find_inputs_sub(struct uaudio_terminal_node *,
                    const uint8_t *, uint8_t, struct uaudio_search_result *);
static const void *uaudio20_mixer_verify_desc(const void *, uint32_t);
static usb_error_t uaudio20_set_speed(struct usb_device *, uint8_t,
                    uint8_t, uint32_t);

/* USB audio v1.0 and v2.0 */

static void     uaudio_chan_fill_info_sub(struct uaudio_softc *,
                    struct usb_device *, uint32_t, uint8_t, uint8_t);
static void     uaudio_chan_fill_info(struct uaudio_softc *,
                    struct usb_device *);
static void     uaudio_mixer_add_ctl_sub(struct uaudio_softc *,
                    struct uaudio_mixer_node *);
static void     uaudio_mixer_add_ctl(struct uaudio_softc *,
                    struct uaudio_mixer_node *);
static void     uaudio_mixer_fill_info(struct uaudio_softc *,
                    struct usb_device *, void *);
static int      uaudio_mixer_signext(uint8_t, int);
static void     uaudio_mixer_init(struct uaudio_softc *, unsigned);
static uint8_t  umidi_convert_to_usb(struct umidi_sub_chan *, uint8_t, uint8_t);
static struct   umidi_sub_chan *umidi_sub_by_fifo(struct usb_fifo *);
static void     umidi_start_read(struct usb_fifo *);
static void     umidi_stop_read(struct usb_fifo *);
static void     umidi_start_write(struct usb_fifo *);
static void     umidi_stop_write(struct usb_fifo *);
static int      umidi_open(struct usb_fifo *, int);
static int      umidi_ioctl(struct usb_fifo *, u_long cmd, void *, int);
static void     umidi_close(struct usb_fifo *, int);
static void     umidi_init(device_t dev);
static int      umidi_attach(device_t dev);
static int      umidi_detach(device_t dev);
static int      uaudio_hid_attach(struct uaudio_softc *sc,
                    struct usb_attach_arg *uaa);
static void     uaudio_hid_detach(struct uaudio_softc *sc);

#ifdef USB_DEBUG
static void     uaudio_chan_dump_ep_desc(
                    const usb_endpoint_descriptor_audio_t *);
#endif

static const struct usb_config
        uaudio_cfg_record[UAUDIO_NCHANBUFS + 1] = {
        [0] = {
                .type = UE_ISOCHRONOUS,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_IN,
                .bufsize = 0,   /* use "wMaxPacketSize * frames" */
                .frames = UAUDIO_NFRAMES,
                .flags = {.short_xfer_ok = 1,},
                .callback = &uaudio_chan_record_callback,
        },

        [1] = {
                .type = UE_ISOCHRONOUS,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_IN,
                .bufsize = 0,   /* use "wMaxPacketSize * frames" */
                .frames = UAUDIO_NFRAMES,
                .flags = {.short_xfer_ok = 1,},
                .callback = &uaudio_chan_record_callback,
        },

        [2] = {
                .type = UE_ISOCHRONOUS,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_OUT,
                .bufsize = 0,   /* use "wMaxPacketSize * frames" */
                .frames = 1,
                .flags = {.no_pipe_ok = 1,.short_xfer_ok = 1,},
                .callback = &uaudio_chan_record_sync_callback,
        },
};

static const struct usb_config
        uaudio_cfg_play[UAUDIO_NCHANBUFS + 1] = {
        [0] = {
                .type = UE_ISOCHRONOUS,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_OUT,
                .bufsize = 0,   /* use "wMaxPacketSize * frames" */
                .frames = UAUDIO_NFRAMES,
                .flags = {.short_xfer_ok = 1,},
                .callback = &uaudio_chan_play_callback,
        },

        [1] = {
                .type = UE_ISOCHRONOUS,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_OUT,
                .bufsize = 0,   /* use "wMaxPacketSize * frames" */
                .frames = UAUDIO_NFRAMES,
                .flags = {.short_xfer_ok = 1,},
                .callback = &uaudio_chan_play_callback,
        },

        [2] = {
                .type = UE_ISOCHRONOUS,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_IN,
                .bufsize = 0,   /* use "wMaxPacketSize * frames" */
                .frames = 1,
                .flags = {.no_pipe_ok = 1,.short_xfer_ok = 1,},
                .callback = &uaudio_chan_play_sync_callback,
        },
};

static const struct usb_config
        uaudio_mixer_config[1] = {
        [0] = {
                .type = UE_CONTROL,
                .endpoint = 0x00,       /* Control pipe */
                .direction = UE_DIR_ANY,
                .bufsize = (sizeof(struct usb_device_request) + 4),
                .callback = &uaudio_mixer_write_cfg_callback,
                .timeout = 1000,        /* 1 second */
        },
};

static const
uint8_t umidi_cmd_to_len[16] = {
        [0x0] = 0,                      /* reserved */
        [0x1] = 0,                      /* reserved */
        [0x2] = 2,                      /* bytes */
        [0x3] = 3,                      /* bytes */
        [0x4] = 3,                      /* bytes */
        [0x5] = 1,                      /* bytes */
        [0x6] = 2,                      /* bytes */
        [0x7] = 3,                      /* bytes */
        [0x8] = 3,                      /* bytes */
        [0x9] = 3,                      /* bytes */
        [0xA] = 3,                      /* bytes */
        [0xB] = 3,                      /* bytes */
        [0xC] = 2,                      /* bytes */
        [0xD] = 2,                      /* bytes */
        [0xE] = 3,                      /* bytes */
        [0xF] = 1,                      /* bytes */
};

static const struct usb_config
        umidi_config[UMIDI_N_TRANSFER] = {
        [UMIDI_TX_TRANSFER] = {
                .type = UE_BULK,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_OUT,
                .bufsize = UMIDI_TX_BUFFER,
                .flags = {.no_pipe_ok = 1},
                .callback = &umidi_bulk_write_callback,
        },

        [UMIDI_RX_TRANSFER] = {
                .type = UE_BULK,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_IN,
                .bufsize = 4,   /* bytes */
                .flags = {.short_xfer_ok = 1,.proxy_buffer = 1,.no_pipe_ok = 1},
                .callback = &umidi_bulk_read_callback,
        },
};

static const struct usb_config
        uaudio_hid_config[UAUDIO_HID_N_TRANSFER] = {
        [UAUDIO_HID_RX_TRANSFER] = {
                .type = UE_INTERRUPT,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_IN,
                .bufsize = 0,   /* use wMaxPacketSize */
                .flags = {.short_xfer_ok = 1,},
                .callback = &uaudio_hid_rx_callback,
        },
};

static device_method_t uaudio_methods[] = {
        DEVMETHOD(device_probe, uaudio_probe),
        DEVMETHOD(device_attach, uaudio_attach),
        DEVMETHOD(device_detach, uaudio_detach),
        DEVMETHOD(device_suspend, bus_generic_suspend),
        DEVMETHOD(device_resume, bus_generic_resume),
        DEVMETHOD(device_shutdown, bus_generic_shutdown),

        DEVMETHOD_END
};

static driver_t uaudio_driver = {
        .name = "uaudio",
        .methods = uaudio_methods,
        .size = sizeof(struct uaudio_softc),
};

/* The following table is derived from Linux's quirks-table.h */ 
static const STRUCT_USB_HOST_ID uaudio_vendor_midi[] = {
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1000, 0) }, /* UX256 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1001, 0) }, /* MU1000 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1002, 0) }, /* MU2000 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1003, 0) }, /* MU500 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1004, 3) }, /* UW500 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1005, 0) }, /* MOTIF6 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1006, 0) }, /* MOTIF7 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1007, 0) }, /* MOTIF8 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1008, 0) }, /* UX96 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1009, 0) }, /* UX16 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x100a, 3) }, /* EOS BX */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x100c, 0) }, /* UC-MX */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x100d, 0) }, /* UC-KX */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x100e, 0) }, /* S08 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x100f, 0) }, /* CLP-150 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1010, 0) }, /* CLP-170 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1011, 0) }, /* P-250 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1012, 0) }, /* TYROS */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1013, 0) }, /* PF-500 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1014, 0) }, /* S90 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1015, 0) }, /* MOTIF-R */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1016, 0) }, /* MDP-5 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1017, 0) }, /* CVP-204 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1018, 0) }, /* CVP-206 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1019, 0) }, /* CVP-208 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x101a, 0) }, /* CVP-210 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x101b, 0) }, /* PSR-1100 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x101c, 0) }, /* PSR-2100 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x101d, 0) }, /* CLP-175 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x101e, 0) }, /* PSR-K1 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x101f, 0) }, /* EZ-J24 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1020, 0) }, /* EZ-250i */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1021, 0) }, /* MOTIF ES 6 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1022, 0) }, /* MOTIF ES 7 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1023, 0) }, /* MOTIF ES 8 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1024, 0) }, /* CVP-301 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1025, 0) }, /* CVP-303 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1026, 0) }, /* CVP-305 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1027, 0) }, /* CVP-307 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1028, 0) }, /* CVP-309 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1029, 0) }, /* CVP-309GP */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x102a, 0) }, /* PSR-1500 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x102b, 0) }, /* PSR-3000 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x102e, 0) }, /* ELS-01/01C */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1030, 0) }, /* PSR-295/293 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1031, 0) }, /* DGX-205/203 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1032, 0) }, /* DGX-305 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1033, 0) }, /* DGX-505 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1034, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1035, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1036, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1037, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1038, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1039, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x103a, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x103b, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x103c, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x103d, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x103e, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x103f, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1040, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1041, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1042, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1043, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1044, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1045, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x104e, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x104f, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1050, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1051, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1052, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1053, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1054, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1055, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1056, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1057, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1058, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1059, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x105a, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x105b, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x105c, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x105d, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x1503, 3) }, /* MOX6/MOX8 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x2000, 0) }, /* DGP-7 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x2001, 0) }, /* DGP-5 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x2002, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x2003, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x5000, 0) }, /* CS1D */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x5001, 0) }, /* DSP1D */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x5002, 0) }, /* DME32 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x5003, 0) }, /* DM2000 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x5004, 0) }, /* 02R96 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x5005, 0) }, /* ACU16-C */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x5006, 0) }, /* NHB32-C */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x5007, 0) }, /* DM1000 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x5008, 0) }, /* 01V96 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x5009, 0) }, /* SPX2000 */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x500a, 0) }, /* PM5D */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x500b, 0) }, /* DME64N */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x500c, 0) }, /* DME24N */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x500d, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x500e, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x500f, 0) }, /* NULL */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x7000, 0) }, /* DTX */
        { USB_VPI(USB_VENDOR_YAMAHA, 0x7010, 0) }, /* UB99 */
};

static const STRUCT_USB_HOST_ID __used uaudio_devs[] = {
        /* Generic USB audio class match */
        {USB_IFACE_CLASS(UICLASS_AUDIO),
         USB_IFACE_SUBCLASS(UISUBCLASS_AUDIOCONTROL),},
        /* Generic USB MIDI class match */
        {USB_IFACE_CLASS(UICLASS_AUDIO),
         USB_IFACE_SUBCLASS(UISUBCLASS_MIDISTREAM),},
};

static unsigned
uaudio_get_child_index_by_dev(struct uaudio_softc *sc, device_t dev)
{
        unsigned i;

        for (i = 0; i != UAUDIO_MAX_CHILD; i++) {
                if (dev == sc->sc_child[i].pcm_device)
                        return (i);
        }
        panic("uaudio_get_child_index_dev: Invalid device: %p\n", dev);
        return (0);
}

static unsigned
uaudio_get_child_index_by_chan(struct uaudio_softc *sc, struct uaudio_chan *ch)
{
        unsigned i;

        for (i = 0; i != UAUDIO_MAX_CHILD; i++) {
                if ((sc->sc_play_chan + i) == ch ||
                    (sc->sc_rec_chan + i) == ch)
                        return (i);
        }
        panic("uaudio_get_child_index_by_chan: Invalid chan: %p\n", ch);
        return (0);
}

static int
uaudio_probe(device_t dev)
{
        struct usb_attach_arg *uaa = device_get_ivars(dev);

        if (uaa->usb_mode != USB_MODE_HOST)
                return (ENXIO);

        /* lookup non-standard device(s) */

        if (usbd_lookup_id_by_uaa(uaudio_vendor_midi,
            sizeof(uaudio_vendor_midi), uaa) == 0) {
                return (BUS_PROBE_SPECIFIC);
        }

        if (uaa->info.bInterfaceClass != UICLASS_AUDIO) {
                if (uaa->info.bInterfaceClass != UICLASS_VENDOR ||
                    usb_test_quirk(uaa, UQ_AU_VENDOR_CLASS) == 0)
                        return (ENXIO);
        }

        /* check for AUDIO control interface */

        if (uaa->info.bInterfaceSubClass == UISUBCLASS_AUDIOCONTROL) {
                if (usb_test_quirk(uaa, UQ_BAD_AUDIO))
                        return (ENXIO);
                else
                        return (BUS_PROBE_GENERIC);
        }

        /* check for MIDI stream */

        if (uaa->info.bInterfaceSubClass == UISUBCLASS_MIDISTREAM) {
                if (usb_test_quirk(uaa, UQ_BAD_MIDI))
                        return (ENXIO);
                else
                        return (BUS_PROBE_GENERIC);
        }
        return (ENXIO);
}

/*
 * Set Cmedia CM6206 S/PDIF settings
 * Source: CM6206 Datasheet v2.3.
 */
static int
uaudio_set_spdif_cm6206(struct uaudio_softc *sc, int flags)
{
        uint8_t cmd[2][4] = {
                {0x20, 0x20, 0x00, 0},
                {0x20, 0x30, 0x02, 1}
        };
        int i;

        if (flags & UAUDIO_SPDIF_OUT)
                cmd[1][1] = 0x00;
        else
                cmd[1][1] = 0x02;

        if (flags & UAUDIO_SPDIF_OUT_96K)
                cmd[0][1] = 0x60;       /* 96K: 3'b110 */

        if (flags & UAUDIO_SPDIF_IN_MIX)
                cmd[1][1] = 0x03;       /* SPDIFMIX */

        for (i = 0; i < 2; i++) {
                if (usbd_req_set_report(sc->sc_udev, NULL,
                    cmd[i], sizeof(cmd[0]),
                    sc->sc_mixer_iface_index, UHID_OUTPUT_REPORT, 0) != 0) {
                        return (ENXIO);
                }
        }
        return (0);
}

static int
uaudio_set_spdif_dummy(struct uaudio_softc *sc, int flags)
{
        return (0);
}

static usb_error_t
uaudio_force_power_save(struct uaudio_softc *sc, uint8_t iface_index)
{
        struct usb_interface *iface;
        usb_error_t err;

        iface = usbd_get_iface(sc->sc_udev, iface_index);
        if (iface == NULL || iface->idesc == NULL)
                return (USB_ERR_INVAL);

        /* check if correct alternate setting is already selected */
        if (iface->alt_index == 0) {
                /* force power save mode by selecting default alternate setting */
                err = usbd_req_set_alt_interface_no(sc->sc_udev, NULL, iface_index,
                    iface->idesc->bAlternateSetting);
        } else {
                err = usbd_set_alt_interface_index(sc->sc_udev, iface_index, 0);
        }
        return (err);
}

static int
uaudio_attach(device_t dev)
{
        struct usb_attach_arg *uaa = device_get_ivars(dev);
        struct uaudio_softc *sc = device_get_softc(dev);
        struct usb_interface_descriptor *id;
        usb_error_t err;
        unsigned i;

        sc->sc_udev = uaa->device;
        sc->sc_mixer_iface_index = uaa->info.bIfaceIndex;
        sc->sc_mixer_iface_no = uaa->info.bIfaceNum;
        sc->sc_config_msg[0].hdr.pm_callback = &uaudio_configure_msg;
        sc->sc_config_msg[0].sc = sc;
        sc->sc_config_msg[1].hdr.pm_callback = &uaudio_configure_msg;
        sc->sc_config_msg[1].sc = sc;

        if (usb_test_quirk(uaa, UQ_AUDIO_SWAP_LR))
                sc->sc_uq_audio_swap_lr = 1;

        if (usb_test_quirk(uaa, UQ_AU_INP_ASYNC))
                sc->sc_uq_au_inp_async = 1;

        if (usb_test_quirk(uaa, UQ_AU_NO_XU))
                sc->sc_uq_au_no_xu = 1;

        if (usb_test_quirk(uaa, UQ_BAD_ADC))
                sc->sc_uq_bad_adc = 1;

        if (usb_test_quirk(uaa, UQ_AU_VENDOR_CLASS))
                sc->sc_uq_au_vendor_class = 1;

        /* set S/PDIF function */
        if (usb_test_quirk(uaa, UQ_AU_SET_SPDIF_CM6206))
                sc->sc_set_spdif_fn = uaudio_set_spdif_cm6206;
        else
                sc->sc_set_spdif_fn = uaudio_set_spdif_dummy;

        umidi_init(dev);

        device_set_usb_desc(dev);

        id = usbd_get_interface_descriptor(uaa->iface);

        /* must fill mixer info before channel info */
        uaudio_mixer_fill_info(sc, uaa->device, id);

        /* fill channel info */
        uaudio_chan_fill_info(sc, uaa->device);

        DPRINTF("audio rev %d.%02x\n",
            sc->sc_audio_rev >> 8,
            sc->sc_audio_rev & 0xff);

        if (sc->sc_mixer_count == 0) {
                if (uaa->info.idVendor == USB_VENDOR_MAUDIO &&
                    (uaa->info.idProduct == USB_PRODUCT_MAUDIO_FASTTRACKULTRA ||
                    uaa->info.idProduct == USB_PRODUCT_MAUDIO_FASTTRACKULTRA8R)) {
                        DPRINTF("Generating mixer descriptors\n");
                        uaudio_mixer_controls_create_ftu(sc);
                }
        }

        DPRINTF("%d mixer controls\n",
            sc->sc_mixer_count);

        for (i = 0; i != UAUDIO_MAX_CHILD; i++) {
                uint8_t x;

                if (sc->sc_play_chan[i].num_alt <= 0)
                        break;

                /*
                 * Need to set a default alternate interface, else
                 * some USB audio devices might go into an infinite
                 * re-enumeration loop:
                 */
                err = uaudio_force_power_save(sc,
                    sc->sc_play_chan[i].usb_alt[0].iface_index);
                if (err) {
                        DPRINTF("setting of alternate index failed: %s!\n",
                            usbd_errstr(err));
                }

                for (x = 0; x != sc->sc_play_chan[i].num_alt; x++) {
                        device_printf(dev, "Play[%u]: %d Hz, %d ch, %s format, "
                            "2x%dms buffer.%s\n", i,
                            sc->sc_play_chan[i].usb_alt[x].sample_rate,
                            sc->sc_play_chan[i].usb_alt[x].channels,
                            sc->sc_play_chan[i].usb_alt[x].p_fmt->description,
                            uaudio_buffer_ms,
                            (x == 0) ? " (selected)" : "");
                }
        }
        if (i == 0)
                device_printf(dev, "No playback.\n");

        for (i = 0; i != UAUDIO_MAX_CHILD; i++) {
                uint8_t x;

                if (sc->sc_rec_chan[i].num_alt <= 0)
                        break;

                /*
                 * Need to set a default alternate interface, else
                 * some USB audio devices might go into an infinite
                 * re-enumeration loop:
                 */
                err = uaudio_force_power_save(sc,
                    sc->sc_rec_chan[i].usb_alt[0].iface_index);
                if (err) {
                        DPRINTF("setting of alternate index failed: %s!\n",
                            usbd_errstr(err));
                }

                for (x = 0; x != sc->sc_rec_chan[i].num_alt; x++) {
                        device_printf(dev, "Record[%u]: %d Hz, %d ch, %s format, "
                            "2x%dms buffer.%s\n", i,
                            sc->sc_rec_chan[i].usb_alt[x].sample_rate,
                            sc->sc_rec_chan[i].usb_alt[x].channels,
                            sc->sc_rec_chan[i].usb_alt[x].p_fmt->description,
                            uaudio_buffer_ms,
                            (x == 0) ? " (selected)" : "");
                }
        }
        if (i == 0)
                device_printf(dev, "No recording.\n");

        if (sc->sc_midi_chan.valid == 0) {
                if (usbd_lookup_id_by_uaa(uaudio_vendor_midi,
                    sizeof(uaudio_vendor_midi), uaa) == 0) {
                        sc->sc_midi_chan.iface_index =
                            (uint8_t)uaa->driver_info;
                        sc->sc_midi_chan.iface_alt_index = 0;
                        sc->sc_midi_chan.valid = 1;
                }
        }

        if (sc->sc_midi_chan.valid) {
                if (umidi_attach(dev)) {
                        goto detach;
                }
                device_printf(dev, "MIDI sequencer.\n");
        } else {
                device_printf(dev, "No MIDI sequencer.\n");
        }

        DPRINTF("doing child attach\n");

        /* attach the children */

        /*
         * Only attach a PCM device if we have a playback, recording
         * or mixer device present:
         */
        for (i = 0; i != UAUDIO_MAX_CHILD; i++) {
                if (sc->sc_play_chan[i].num_alt <= 0 &&
                    sc->sc_rec_chan[i].num_alt <= 0 &&
                    sc->sc_child[i].mix_info == 0)
                        continue;
                sc->sc_child[i].pcm_device =
                    device_add_child(dev, "pcm", DEVICE_UNIT_ANY);

                if (sc->sc_child[i].pcm_device == NULL) {
                        DPRINTF("out of memory\n");
                        goto detach;
                }
        }

        bus_attach_children(dev);

        if (uaudio_handle_hid) {
                if (uaudio_hid_attach(sc, uaa) == 0) {
                        device_printf(dev, "HID volume keys found.\n");
                } else {
                        device_printf(dev, "No HID volume keys found.\n");
                }
        }

        /* reload all mixer settings */
        uaudio_mixer_reload_all(sc);

        /* enable S/PDIF output, if any */
        if (sc->sc_set_spdif_fn(sc,
            UAUDIO_SPDIF_OUT | UAUDIO_SPDIF_OUT_48K) != 0) {
                device_printf(dev, "Failed to enable S/PDIF at 48K\n");
        }
        return (0);                     /* success */

detach:
        uaudio_detach(dev);
        return (ENXIO);
}

static void
uaudio_pcm_setflags(device_t dev, uint32_t flags)
{
        pcm_setflags(dev, pcm_getflags(dev) | flags);
}

int
uaudio_attach_sub(device_t dev, kobj_class_t mixer_class, kobj_class_t chan_class)
{
        struct uaudio_softc *sc = device_get_softc(device_get_parent(dev));
        unsigned i = uaudio_get_child_index_by_dev(sc, dev);
        char status[SND_STATUSLEN];

        uaudio_mixer_init(sc, i);

        if (sc->sc_uq_audio_swap_lr) {
                DPRINTF("hardware has swapped left and right\n");
                /* uaudio_pcm_setflags(dev, SD_F_PSWAPLR); */
        }
        if (sc->sc_play_chan[i].num_alt > 0 &&
            (sc->sc_child[i].mix_info & SOUND_MASK_PCM) == 0) {
                DPRINTF("software controlled main volume\n");

                /*
                 * Emulate missing pcm mixer controller
                 * through FEEDER_VOLUME
                 */
                uaudio_pcm_setflags(dev, SD_F_SOFTPCMVOL);
        }
        if (sc->sc_pcm_bitperfect) {
                DPRINTF("device needs bitperfect by default\n");
                uaudio_pcm_setflags(dev, SD_F_BITPERFECT);
        }
        if (mixer_init(dev, mixer_class, sc))
                goto detach;
        sc->sc_child[i].mixer_init = 1;

        mixer_hwvol_init(dev);

        device_set_descf(dev, "%s %s",
            usb_get_manufacturer(sc->sc_udev),
            usb_get_product(sc->sc_udev));

        snprintf(status, sizeof(status), "on %s",
            device_get_nameunit(device_get_parent(dev)));

        pcm_init(dev, sc);

        uaudio_pcm_setflags(dev, SD_F_MPSAFE);

        if (sc->sc_play_chan[i].num_alt > 0) {
                sc->sc_play_chan[i].priv_sc = sc;
                pcm_addchan(dev, PCMDIR_PLAY, chan_class,
                    &sc->sc_play_chan[i]);
        }

        if (sc->sc_rec_chan[i].num_alt > 0) {
                sc->sc_rec_chan[i].priv_sc = sc;
                pcm_addchan(dev, PCMDIR_REC, chan_class,
                    &sc->sc_rec_chan[i]);
        }
        if (pcm_register(dev, status))
                goto detach;
        sc->sc_child[i].pcm_registered = 1;

        uaudio_mixer_register_sysctl(sc, dev, i);

        SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO,
            "feedback_rate", CTLFLAG_RD, &sc->sc_play_chan[i].feedback_rate,
            0, "Feedback sample rate in Hz");

        return (0);                     /* success */

detach:
        uaudio_detach_sub(dev);
        return (ENXIO);
}

int
uaudio_detach_sub(device_t dev)
{
        struct uaudio_softc *sc = device_get_softc(device_get_parent(dev));
        unsigned i = uaudio_get_child_index_by_dev(sc, dev);
        int error = 0;

        if (sc->sc_child[i].pcm_registered) {
                error = pcm_unregister(dev);
        } else if (sc->sc_child[i].mixer_init) {
                error = mixer_uninit(dev);
        }

        return (error);
}

static int
uaudio_detach(device_t dev)
{
        struct uaudio_softc *sc = device_get_softc(dev);
        unsigned i;

        /*
         * Stop USB transfers early so that any audio applications
         * will time out and close opened /dev/dspX.Y device(s), if
         * any.
         */
        usb_proc_explore_lock(sc->sc_udev);
        for (i = 0; i != UAUDIO_MAX_CHILD; i++) {
                sc->sc_play_chan[i].operation = CHAN_OP_DRAIN;
                sc->sc_rec_chan[i].operation = CHAN_OP_DRAIN;
        }
        usb_proc_explore_mwait(sc->sc_udev,
            &sc->sc_config_msg[0], &sc->sc_config_msg[1]);
        usb_proc_explore_unlock(sc->sc_udev);

        for (i = 0; i != UAUDIO_MAX_CHILD; i++) {
                usbd_transfer_unsetup(sc->sc_play_chan[i].xfer, UAUDIO_NCHANBUFS + 1);
                usbd_transfer_unsetup(sc->sc_rec_chan[i].xfer, UAUDIO_NCHANBUFS + 1);
        }

        uaudio_hid_detach(sc);

        if (bus_generic_detach(dev) != 0) {
                DPRINTF("detach failed!\n");
        }

        umidi_detach(dev);

        /* free mixer data */

        uaudio_mixer_ctl_free(sc);

        /* disable S/PDIF output, if any */
        (void) sc->sc_set_spdif_fn(sc, 0);

        return (0);
}

static uint32_t
uaudio_get_interval_frames(const usb_endpoint_descriptor_audio_t *ed)
{
        uint32_t frames = 1;
        /* Isochronous transfer interval is 2^(bInterval - 1) frames. */
        if (ed->bInterval >= 1 && ed->bInterval <= 16)
                frames = (1 << (ed->bInterval - 1));
        /* Limit transfer interval to maximum number of frames. */
        if (frames > UAUDIO_NFRAMES)
                frames = UAUDIO_NFRAMES;
        return (frames);
}

static uint32_t
uaudio_get_buffer_ms(struct uaudio_softc *sc, uint32_t int_frames)
{
        uint32_t ms = 1;
        uint32_t fps = usbd_get_isoc_fps(sc->sc_udev);
        /* Make sure a whole USB transfer interval fits into the buffer. */
        if (fps >= 1000 && int_frames > 0 && int_frames <= UAUDIO_NFRAMES) {
                /* Convert interval frames to milliseconds. */
                ms = ((int_frames * 1000) / fps);
        }
        /* Respect minimum buffer length set through buffer_ms tunable. */
        if (ms < uaudio_buffer_ms)
                ms = uaudio_buffer_ms;
        /* Limit buffer length to 8 milliseconds. */
        if (ms > UAUDIO_BUFFER_MS_MAX)
                ms = UAUDIO_BUFFER_MS_MAX;
        return (ms);
}

static uint32_t
uaudio_get_buffer_size(struct uaudio_chan *ch, uint8_t alt)
{
        struct uaudio_chan_alt *chan_alt = &ch->usb_alt[alt];
        uint32_t int_frames, ms, buf_size;
        /* USB transfer interval in frames, from endpoint descriptor. */
        int_frames = uaudio_get_interval_frames(chan_alt->p_ed1);
        /* Buffer length in milliseconds, and in bytes of audio data. */
        ms = uaudio_get_buffer_ms(ch->priv_sc, int_frames);
        buf_size = chan_alt->sample_size *
            howmany(chan_alt->sample_rate * ms, 1000);
        return (buf_size);
}

static uint32_t
uaudio_max_buffer_size(struct uaudio_chan *ch, uint8_t alt)
{
        struct uaudio_chan_alt *chan_alt = &ch->usb_alt[alt];
        uint32_t buf_size;
        /* Maximum buffer length is 8 milliseconds. */
        buf_size = chan_alt->sample_size *
            howmany(chan_alt->sample_rate * UAUDIO_BUFFER_MS_MAX, 1000);
        return (buf_size);
}

static void
uaudio_configure_msg_sub(struct uaudio_softc *sc,
    struct uaudio_chan *chan, int dir)
{
        struct uaudio_chan_alt *chan_alt;
        uint32_t frames;
        uint32_t buf_size;
        uint16_t fps;
        uint8_t next_alt;
        uint8_t fps_shift;
        uint8_t operation;
        usb_error_t err;

        if (chan->num_alt <= 0)
                return;

        DPRINTF("\n");

        usb_proc_explore_lock(sc->sc_udev);
        operation = chan->operation;
        switch (operation) {
        case CHAN_OP_START:
        case CHAN_OP_STOP:
                chan->operation = CHAN_OP_NONE;
                break;
        default:
                break;
        }
        usb_proc_explore_unlock(sc->sc_udev);

        switch (operation) {
        case CHAN_OP_STOP:
                /* Unsetup prior USB transfers, if any. */
                usbd_transfer_unsetup(chan->xfer, UAUDIO_NCHANBUFS + 1);

                mtx_lock(&chan->lock);
                chan->cur_alt = CHAN_MAX_ALT;
                mtx_unlock(&chan->lock);

                /*
                 * The first alternate setting is typically used for
                 * power saving mode. Set this alternate setting as
                 * part of entering stop.
                 */
                err = usbd_set_alt_interface_index(sc->sc_udev, chan->iface_index, 0);
                if (err) {
                        DPRINTF("setting of default alternate index failed: %s!\n",
                            usbd_errstr(err));
                }
                return;

        case CHAN_OP_START:
                /* Unsetup prior USB transfers, if any. */
                usbd_transfer_unsetup(chan->xfer, UAUDIO_NCHANBUFS + 1);
                break;

        default:
                return;
        }

        mtx_lock(&chan->lock);
        next_alt = chan->set_alt;
        mtx_unlock(&chan->lock);

        chan_alt = chan->usb_alt + next_alt;

        err = usbd_set_alt_interface_index(sc->sc_udev,
            chan_alt->iface_index, chan_alt->iface_alt_index);
        if (err) {
                DPRINTF("setting of alternate index failed: %s!\n",
                    usbd_errstr(err));
                goto error;
        }

        /*
         * Only set the sample rate if the channel reports that it
         * supports the frequency control.
         */

        if (sc->sc_audio_rev >= UAUDIO_VERSION_30) {
                /* FALLTHROUGH */
        } else if (sc->sc_audio_rev >= UAUDIO_VERSION_20) {
                unsigned int x;
          
                for (x = 0; x != 256; x++) {
                        if (dir == PCMDIR_PLAY) {
                                if (!(sc->sc_mixer_clocks.bit_output[x / 8] &
                                    (1 << (x % 8)))) {
                                        continue;
                                }
                        } else {
                                if (!(sc->sc_mixer_clocks.bit_input[x / 8] &
                                    (1 << (x % 8)))) {
                                        continue;
                                }
                        }

                        if (uaudio20_set_speed(sc->sc_udev,
                            sc->sc_mixer_iface_no, x, chan_alt->sample_rate)) {
                                /*
                                 * If the endpoint is adaptive setting
                                 * the speed may fail.
                                 */
                                DPRINTF("setting of sample rate failed! "
                                    "(continuing anyway)\n");
                        }
                }
        } else if (chan_alt->p_sed.v1->bmAttributes & UA_SED_FREQ_CONTROL) {
                if (uaudio_set_speed(sc->sc_udev,
                    chan_alt->p_ed1->bEndpointAddress, chan_alt->sample_rate)) {
                        /*
                         * If the endpoint is adaptive setting the
                         * speed may fail.
                         */
                        DPRINTF("setting of sample rate failed! "
                            "(continuing anyway)\n");
                }
        }
        if (usbd_transfer_setup(sc->sc_udev, &chan_alt->iface_index, chan->xfer,
            chan_alt->usb_cfg, UAUDIO_NCHANBUFS + 1, chan, &chan->lock)) {
                DPRINTF("could not allocate USB transfers!\n");
                goto error;
        }

        fps = usbd_get_isoc_fps(sc->sc_udev);

        if (fps < 8000) {
                /* FULL speed USB */
                frames = uaudio_buffer_ms;
        } else {
                /* HIGH speed USB */
                frames = uaudio_buffer_ms * 8;
        }

        fps_shift = usbd_xfer_get_fps_shift(chan->xfer[0]);

        /* down shift number of frames per second, if any */
        fps >>= fps_shift;
        frames >>= fps_shift;

        /* bytes per frame should not be zero */
        chan->bytes_per_frame[0] =
            ((chan_alt->sample_rate / fps) * chan_alt->sample_size);
        chan->bytes_per_frame[1] = howmany(chan_alt->sample_rate, fps) *
            chan_alt->sample_size;

        /* setup data rate dithering, if any */
        chan->frames_per_second = fps;
        chan->sample_rem = chan_alt->sample_rate % fps;
        chan->sample_curr = 0;

        /* compute required buffer size */
        buf_size = (chan->bytes_per_frame[1] * frames);

        if (buf_size > (chan->end - chan->start)) {
                DPRINTF("buffer size is too big\n");
                goto error;
        }

        chan->intr_frames = frames;

        DPRINTF("fps=%d sample_rem=%d\n", (int)fps, (int)chan->sample_rem);

        if (chan->intr_frames == 0) {
                DPRINTF("frame shift is too high!\n");
                goto error;
        }

#if (UAUDIO_NCHANBUFS != 2)
#error "Please update code below!"
#endif

        mtx_lock(&chan->lock);
        chan->cur_alt = next_alt;
        usbd_transfer_start(chan->xfer[0]);
        usbd_transfer_start(chan->xfer[1]);
        mtx_unlock(&chan->lock);
        return;
error:
        usbd_transfer_unsetup(chan->xfer, UAUDIO_NCHANBUFS + 1);

        mtx_lock(&chan->lock);
        chan->cur_alt = CHAN_MAX_ALT;
        mtx_unlock(&chan->lock);
}

static void
uaudio_configure_msg(struct usb_proc_msg *pm)
{
        struct uaudio_softc *sc = ((struct uaudio_configure_msg *)pm)->sc;
        unsigned i;

        usb_proc_explore_unlock(sc->sc_udev);
        for (i = 0; i != UAUDIO_MAX_CHILD; i++) {
                uaudio_configure_msg_sub(sc, &sc->sc_play_chan[i], PCMDIR_PLAY);
                uaudio_configure_msg_sub(sc, &sc->sc_rec_chan[i], PCMDIR_REC);
        }
        usb_proc_explore_lock(sc->sc_udev);
}

/*========================================================================*
 * AS - Audio Stream - routines
 *========================================================================*/

#ifdef USB_DEBUG
static void
uaudio_chan_dump_ep_desc(const usb_endpoint_descriptor_audio_t *ed)
{
        if (ed) {
                DPRINTF("endpoint=%p bLength=%d bDescriptorType=%d \n"
                    "bEndpointAddress=%d bmAttributes=0x%x \n"
                    "wMaxPacketSize=%d bInterval=%d \n"
                    "bRefresh=%d bSynchAddress=%d\n",
                    ed, ed->bLength, ed->bDescriptorType,
                    ed->bEndpointAddress, ed->bmAttributes,
                    UGETW(ed->wMaxPacketSize), ed->bInterval,
                    UEP_HAS_REFRESH(ed) ? ed->bRefresh : 0,
                    UEP_HAS_SYNCADDR(ed) ? ed->bSynchAddress : 0);
        }
}

#endif

/*
 * The following is a workaround for broken no-name USB audio devices
 * sold by dealextreme called "3D sound". The problem is that the
 * manufacturer computed wMaxPacketSize is too small to hold the
 * actual data sent. In other words the device sometimes sends more
 * data than it actually reports it can send in a single isochronous
 * packet.
 */
static void
uaudio_record_fix_fs(usb_endpoint_descriptor_audio_t *ep,
    uint32_t xps, uint32_t add)
{
        uint32_t mps;

        mps = UGETW(ep->wMaxPacketSize);

        /*
         * If the device indicates it can send more data than what the
         * sample rate indicates, we apply the workaround.
         */
        if (mps > xps) {
                /* allow additional data */
                xps += add;

                /* check against the maximum USB 1.x length */
                if (xps > 1023)
                        xps = 1023;

                /* check if we should do an update */
                if (mps < xps) {
                        /* simply update the wMaxPacketSize field */
                        USETW(ep->wMaxPacketSize, xps);
                        DPRINTF("Workaround: Updated wMaxPacketSize "
                            "from %d to %d bytes.\n",
                            (int)mps, (int)xps);
                }
        }
}

static usb_error_t
uaudio20_check_rate(struct usb_device *udev, uint8_t iface_no,
    uint8_t clockid, uint32_t rate)
{
        struct usb_device_request req;
        usb_error_t error;
#define UAUDIO20_MAX_RATES 32   /* we support at maximum 32 rates */
        uint8_t data[2 + UAUDIO20_MAX_RATES * 12];
        uint16_t actlen;
        uint16_t rates;
        uint16_t x;

        DPRINTFN(6, "ifaceno=%d clockid=%d rate=%u\n",
            iface_no, clockid, rate);

        req.bmRequestType = UT_READ_CLASS_INTERFACE;
        req.bRequest = UA20_CS_RANGE;
        USETW2(req.wValue, UA20_CS_SAM_FREQ_CONTROL, 0);
        USETW2(req.wIndex, clockid, iface_no);
        /*
         * Assume there is at least one rate to begin with, else some
         * devices might refuse to return the USB descriptor:
         */
        USETW(req.wLength, (2 + 1 * 12));

        error = usbd_do_request_flags(udev, NULL, &req, data,
            USB_SHORT_XFER_OK, &actlen, USB_DEFAULT_TIMEOUT);

        if (error != 0 || actlen < 2) {
                /*
                 * Likely the descriptor doesn't fit into the supplied
                 * buffer. Try using a larger buffer and see if that
                 * helps:
                 */
                rates = min(UAUDIO20_MAX_RATES, (255 - 2) / 12);
                error = USB_ERR_INVAL;
        } else {
                rates = UGETW(data);

                if (rates > UAUDIO20_MAX_RATES) {
                        DPRINTF("Too many rates truncating to %d\n", UAUDIO20_MAX_RATES);
                        rates = UAUDIO20_MAX_RATES;
                        error = USB_ERR_INVAL;
                } else if (rates > 1) {
                        DPRINTF("Need to read full rate descriptor\n");
                        error = USB_ERR_INVAL;
                }
        }

        if (error != 0) {
                /*
                 * Try to read full rate descriptor.
                 */
                actlen = (2 + rates * 12);

                USETW(req.wLength, actlen);

                error = usbd_do_request_flags(udev, NULL, &req, data,
                    USB_SHORT_XFER_OK, &actlen, USB_DEFAULT_TIMEOUT);

                if (error != 0 || actlen < 2)
                        return (USB_ERR_INVAL);

                rates = UGETW(data);
        }

        actlen = (actlen - 2) / 12;

        if (rates > actlen) {
                DPRINTF("Too many rates truncating to %d\n", actlen);
                rates = actlen;
        }

        for (x = 0; x != rates; x++) {
                uint32_t min = UGETDW(data + 2 + (12 * x));
                uint32_t max = UGETDW(data + 6 + (12 * x));
                uint32_t res = UGETDW(data + 10 + (12 * x));

                if (res == 0) {
                        DPRINTF("Zero residue\n");
                        res = 1;
                }

                if (min > max) {
                        DPRINTF("Swapped max and min\n");
                        uint32_t temp;
                        temp = min;
                        min = max;
                        max = temp;
                }

                if (rate >= min && rate <= max &&
                    (((rate - min) % res) == 0)) {
                        return (0);
                }
        }
        return (USB_ERR_INVAL);
}

static struct uaudio_chan *
uaudio_get_chan(struct uaudio_softc *sc, struct uaudio_chan *chan,
    uint8_t iface_index)
{
        unsigned i;

        for (i = 0; i != UAUDIO_MAX_CHILD; i++, chan++) {
                if (chan->num_alt == 0) {
                        chan->iface_index = iface_index;
                        return (chan);
                } else if (chan->iface_index == iface_index)
                        return (chan);
        }
        return (NULL);
}

static void
uaudio_chan_fill_info_sub(struct uaudio_softc *sc, struct usb_device *udev,
    uint32_t rate, uint8_t channels, uint8_t bit_resolution)
{
        struct usb_descriptor *desc = NULL;
        union uaudio_asid asid = { NULL };
        union uaudio_asf1d asf1d = { NULL };
        union uaudio_sed sed = { NULL };
        struct usb_midi_streaming_endpoint_descriptor *msid = NULL;
        usb_endpoint_descriptor_audio_t *ed1 = NULL;
        const struct usb_audio_control_descriptor *acdp = NULL;
        struct usb_config_descriptor *cd = usbd_get_config_descriptor(udev);
        struct usb_interface_descriptor *id;
        const struct uaudio_format *p_fmt = NULL;
        struct uaudio_chan *chan;
        struct uaudio_chan_alt *chan_alt;
        uint32_t format;
        uint16_t curidx = 0xFFFF;
        uint16_t lastidx = 0xFFFF;
        uint16_t alt_index = 0;
        uint16_t audio_rev = 0;
        uint16_t x;
        uint8_t ep_dir;
        uint8_t bChannels;
        uint8_t bBitResolution;
        uint8_t audio_if = 0;
        uint8_t midi_if = 0;
        uint8_t uma_if_class;

        while ((desc = usb_desc_foreach(cd, desc))) {
                if ((desc->bDescriptorType == UDESC_INTERFACE) &&
                    (desc->bLength >= sizeof(*id))) {
                        id = (void *)desc;

                        if (id->bInterfaceNumber != lastidx) {
                                lastidx = id->bInterfaceNumber;
                                curidx++;
                                alt_index = 0;

                        } else {
                                alt_index++;
                        }

                        if ((!(sc->sc_hid.flags & UAUDIO_HID_VALID)) &&
                            (id->bInterfaceClass == UICLASS_HID) &&
                            (id->bInterfaceSubClass == 0) &&
                            (id->bInterfaceProtocol == 0) &&
                            (alt_index == 0) &&
                            usbd_get_iface(udev, curidx) != NULL) {
                                DPRINTF("Found HID interface at %d\n",
                                    curidx);
                                sc->sc_hid.flags |= UAUDIO_HID_VALID;
                                sc->sc_hid.iface_index = curidx;
                        }

                        uma_if_class =
                            ((id->bInterfaceClass == UICLASS_AUDIO) ||
                            ((id->bInterfaceClass == UICLASS_VENDOR) &&
                            (sc->sc_uq_au_vendor_class != 0)));

                        if ((uma_if_class != 0) &&
                            (id->bInterfaceSubClass == UISUBCLASS_AUDIOSTREAM)) {
                                audio_if = 1;
                        } else {
                                audio_if = 0;
                        }

                        if ((uma_if_class != 0) &&
                            (id->bInterfaceSubClass == UISUBCLASS_MIDISTREAM)) {
                                /*
                                 * XXX could allow multiple MIDI interfaces
                                 */
                                midi_if = 1;

                                if ((sc->sc_midi_chan.valid == 0) &&
                                    (usbd_get_iface(udev, curidx) != NULL)) {
                                        sc->sc_midi_chan.iface_index = curidx;
                                        sc->sc_midi_chan.iface_alt_index = alt_index;
                                        sc->sc_midi_chan.valid = 1;
                                }
                        } else {
                                midi_if = 0;
                        }
                        asid.v1 = NULL;
                        asf1d.v1 = NULL;
                        ed1 = NULL;
                        sed.v1 = NULL;

                        /*
                         * There can only be one USB audio instance
                         * per USB device. Grab all USB audio
                         * interfaces on this USB device so that we
                         * don't attach USB audio twice:
                         */
                        if (alt_index == 0 && curidx != sc->sc_mixer_iface_index &&
                            (id->bInterfaceClass == UICLASS_AUDIO || audio_if != 0 ||
                            midi_if != 0)) {
                                usbd_set_parent_iface(sc->sc_udev, curidx,
                                    sc->sc_mixer_iface_index);
                        }
                }

                if (audio_if == 0) {
                        if (midi_if == 0) {
                                if ((acdp == NULL) &&
                                    (desc->bDescriptorType == UDESC_CS_INTERFACE) &&
                                    (desc->bDescriptorSubtype == UDESCSUB_AC_HEADER) &&
                                    (desc->bLength >= sizeof(*acdp))) {
                                        acdp = (void *)desc;
                                        audio_rev = UGETW(acdp->bcdADC);
                                }
                        } else {
                                msid = (void *)desc;

                                /* get the maximum number of embedded jacks in use, if any */
                                if (msid->bLength >= sizeof(*msid) &&
                                    msid->bDescriptorType == UDESC_CS_ENDPOINT &&
                                    msid->bDescriptorSubtype == MS_GENERAL &&
                                    msid->bNumEmbMIDIJack > sc->sc_midi_chan.max_emb_jack) {
                                        sc->sc_midi_chan.max_emb_jack = msid->bNumEmbMIDIJack;
                                }
                        }
                        /*
                         * Don't collect any USB audio descriptors if
                         * this is not an USB audio stream interface.
                         */
                        continue;
                }

                if ((acdp != NULL || sc->sc_uq_au_vendor_class != 0) &&
                    (desc->bDescriptorType == UDESC_CS_INTERFACE) &&
                    (desc->bDescriptorSubtype == AS_GENERAL) &&
                    (asid.v1 == NULL)) {
                        if (audio_rev >= UAUDIO_VERSION_30) {
                                /* FALLTHROUGH */
                        } else if (audio_rev >= UAUDIO_VERSION_20) {
                                if (desc->bLength >= sizeof(*asid.v2)) {
                                        asid.v2 = (void *)desc;
                                }
                        } else {
                                if (desc->bLength >= sizeof(*asid.v1)) {
                                        asid.v1 = (void *)desc;
                                }
                        }
                }
                if ((acdp != NULL || sc->sc_uq_au_vendor_class != 0) &&
                    (desc->bDescriptorType == UDESC_CS_INTERFACE) &&
                    (desc->bDescriptorSubtype == FORMAT_TYPE) &&
                    (asf1d.v1 == NULL)) {
                        if (audio_rev >= UAUDIO_VERSION_30) {
                                /* FALLTHROUGH */
                        } else if (audio_rev >= UAUDIO_VERSION_20) {
                                if (desc->bLength >= sizeof(*asf1d.v2))
                                        asf1d.v2 = (void *)desc;
                        } else {
                                if (desc->bLength >= sizeof(*asf1d.v1)) {
                                        asf1d.v1 = (void *)desc;

                                        if (asf1d.v1->bFormatType != FORMAT_TYPE_I) {
                                                DPRINTFN(11, "ignored bFormatType = %d\n",
                                                    asf1d.v1->bFormatType);
                                                asf1d.v1 = NULL;
                                                continue;
                                        }
                                        if (desc->bLength < (sizeof(*asf1d.v1) +
                                            ((asf1d.v1->bSamFreqType == 0) ? 6 :
                                            (asf1d.v1->bSamFreqType * 3)))) {
                                                DPRINTFN(11, "invalid descriptor, "
                                                    "too short\n");
                                                asf1d.v1 = NULL;
                                                continue;
                                        }
                                }
                        }
                }
                if ((desc->bDescriptorType == UDESC_ENDPOINT) &&
                    (desc->bLength >= UEP_MINSIZE) &&
                    (ed1 == NULL)) {
                        ed1 = (void *)desc;
                        if (UE_GET_XFERTYPE(ed1->bmAttributes) != UE_ISOCHRONOUS) {
                                ed1 = NULL;
                                continue;
                        }
                }
                if ((acdp != NULL || sc->sc_uq_au_vendor_class != 0) &&
                    (desc->bDescriptorType == UDESC_CS_ENDPOINT) &&
                    (desc->bDescriptorSubtype == AS_GENERAL) &&
                    (sed.v1 == NULL)) {
                        if (audio_rev >= UAUDIO_VERSION_30) {
                                /* FALLTHROUGH */
                        } else if (audio_rev >= UAUDIO_VERSION_20) {
                                if (desc->bLength >= sizeof(*sed.v2))
                                        sed.v2 = (void *)desc;
                        } else {
                                if (desc->bLength >= sizeof(*sed.v1))
                                        sed.v1 = (void *)desc;
                        }
                }
                if (asid.v1 == NULL || asf1d.v1 == NULL ||
                    ed1 == NULL || sed.v1 == NULL) {
                        /* need more descriptors */
                        continue;
                }

                ep_dir = UE_GET_DIR(ed1->bEndpointAddress);

                /* We ignore sync endpoint information until further. */

                if (audio_rev >= UAUDIO_VERSION_30) {
                        goto next_ep;
                } else if (audio_rev >= UAUDIO_VERSION_20) {
                        uint32_t dwFormat;

                        dwFormat = UGETDW(asid.v2->bmFormats);
                        bChannels = asid.v2->bNrChannels;
                        bBitResolution = asf1d.v2->bSubslotSize * 8;

                        if ((bChannels != channels) ||
                            (bBitResolution != bit_resolution)) {
                                DPRINTF("Wrong number of channels\n");
                                goto next_ep;
                        }

                        for (p_fmt = uaudio20_formats;
                            p_fmt->wFormat != 0; p_fmt++) {
                                if ((p_fmt->wFormat & dwFormat) &&
                                    (p_fmt->bPrecision == bBitResolution))
                                        break;
                        }

                        if (p_fmt->wFormat == 0) {
                                DPRINTF("Unsupported audio format\n");
                                goto next_ep;
                        }

                        for (x = 0; x != 256; x++) {
                                if (ep_dir == UE_DIR_OUT) {
                                        if (!(sc->sc_mixer_clocks.bit_output[x / 8] &
                                            (1 << (x % 8)))) {
                                                continue;
                                        }
                                } else {
                                        if (!(sc->sc_mixer_clocks.bit_input[x / 8] &
                                            (1 << (x % 8)))) {
                                                continue;
                                        }
                                }

                                DPRINTF("Checking clock ID=%d\n", x);

                                if (uaudio20_check_rate(udev,
                                    sc->sc_mixer_iface_no, x, rate)) {
                                        DPRINTF("Unsupported sampling "
                                            "rate, id=%d\n", x);
                                        goto next_ep;
                                }
                        }
                } else {
                        uint16_t wFormat;

                        wFormat = UGETW(asid.v1->wFormatTag);
                        bChannels = asf1d.v1->bNrChannels;
                        bBitResolution = asf1d.v1->bSubFrameSize * 8;

                        if (asf1d.v1->bSamFreqType == 0) {
                                DPRINTFN(16, "Sample rate: %d-%dHz\n",
                                    UA_SAMP_LO(asf1d.v1),
                                    UA_SAMP_HI(asf1d.v1));

                                if ((rate >= UA_SAMP_LO(asf1d.v1)) &&
                                    (rate <= UA_SAMP_HI(asf1d.v1)))
                                        goto found_rate;
                        } else {
                                for (x = 0; x < asf1d.v1->bSamFreqType; x++) {
                                        DPRINTFN(16, "Sample rate = %dHz\n",
                                            UA_GETSAMP(asf1d.v1, x));

                                        if (rate == UA_GETSAMP(asf1d.v1, x))
                                                goto found_rate;
                                }
                        }
                        goto next_ep;

        found_rate:
                        for (p_fmt = uaudio10_formats;
                            p_fmt->wFormat != 0; p_fmt++) {
                                if ((p_fmt->wFormat == wFormat) &&
                                    (p_fmt->bPrecision == bBitResolution))
                                        break;
                        }
                        if (p_fmt->wFormat == 0) {
                                DPRINTF("Unsupported audio format\n");
                                goto next_ep;
                        }

                        if ((bChannels != channels) ||
                            (bBitResolution != bit_resolution)) {
                                DPRINTF("Wrong number of channels\n");
                                goto next_ep;
                        }
                }

                chan = uaudio_get_chan(sc, (ep_dir == UE_DIR_OUT) ? &sc->sc_play_chan[0] :
                    &sc->sc_rec_chan[0], curidx);
                if (chan == NULL) {
                        DPRINTF("More than %d sub devices. (skipped)\n", UAUDIO_MAX_CHILD);
                        goto next_ep;
                }

                if (usbd_get_iface(udev, curidx) == NULL) {
                        DPRINTF("Interface is not valid\n");
                        goto next_ep;
                }
                if (chan->num_alt == CHAN_MAX_ALT) {
                        DPRINTF("Too many alternate settings\n");
                        goto next_ep;
                }
                chan->set_alt = 0;
                chan->cur_alt = CHAN_MAX_ALT;

                chan_alt = &chan->usb_alt[chan->num_alt++];

#ifdef USB_DEBUG
                uaudio_chan_dump_ep_desc(ed1);
#endif
                DPRINTF("Sample rate = %dHz, channels = %d, "
                    "bits = %d, format = %s, ep 0x%02x, chan %p\n", rate, channels,
                    bit_resolution, p_fmt->description, ed1->bEndpointAddress, chan);

                chan_alt->sample_rate = rate;
                chan_alt->p_asf1d = asf1d;
                chan_alt->p_ed1 = ed1;
                chan_alt->p_fmt = p_fmt;
                chan_alt->p_sed = sed;
                chan_alt->iface_index = curidx;
                chan_alt->iface_alt_index = alt_index;

                if (ep_dir == UE_DIR_IN)
                        chan_alt->usb_cfg = uaudio_cfg_record;
                else
                        chan_alt->usb_cfg = uaudio_cfg_play;

                chan_alt->sample_size = (channels * p_fmt->bPrecision) / 8;
                chan_alt->channels = channels;

                if (ep_dir == UE_DIR_IN &&
                    usbd_get_speed(udev) == USB_SPEED_FULL) {
                        uaudio_record_fix_fs(ed1,
                            chan_alt->sample_size * (rate / 1000),
                            chan_alt->sample_size * (rate / 4000));
                }

                /* setup play/record format */

                format = chan_alt->p_fmt->freebsd_fmt;

                /* get default SND_FORMAT() */
                format = SND_FORMAT(format, chan_alt->channels, 0);

                switch (chan_alt->channels) {
                uint32_t temp_fmt;
                case 1:
                case 2:
                        /* mono and stereo */
                        break;
                default:
                        /* surround and more */
                        temp_fmt = feeder_matrix_default_format(format);
                        /* if multichannel, then format can be zero */
                        if (temp_fmt != 0)
                                format = temp_fmt;
                        break;
                }

                /* check if format is not supported */
                if (format == 0) {
                        DPRINTF("The selected audio format is not supported\n");
                        chan->num_alt--;
                        goto next_ep;
                }
                if (chan->num_alt > 1) {
                        /* we only accumulate one format at different sample rates */
                        if (chan->pcm_format[0] != format) {
                                DPRINTF("Multiple formats is not supported\n");
                                chan->num_alt--;
                                goto next_ep;
                        }
                        /* ignore if duplicate sample rate entry */
                        if (rate == chan->usb_alt[chan->num_alt - 2].sample_rate) {
                                DPRINTF("Duplicate sample rate detected\n");
                                chan->num_alt--;
                                goto next_ep;
                        }
                }
                chan->pcm_cap.fmtlist = chan->pcm_format;
                chan->pcm_cap.fmtlist[0] = format;

                /* check if device needs bitperfect */
                if (chan_alt->channels > UAUDIO_MATRIX_MAX)
                        sc->sc_pcm_bitperfect = 1;

                if (rate < chan->pcm_cap.minspeed || chan->pcm_cap.minspeed == 0)
                        chan->pcm_cap.minspeed = rate;
                if (rate > chan->pcm_cap.maxspeed || chan->pcm_cap.maxspeed == 0)
                        chan->pcm_cap.maxspeed = rate;

        next_ep:
                sed.v1 = NULL;
                ed1 = NULL;
        }
}

/* This structure defines all the supported rates. */

static const uint32_t uaudio_rate_list[CHAN_MAX_ALT] = {
        384000,
        352800,
        192000,
        176400,
        96000,
        88200,
        88000,
        80000,
        72000,
        64000,
        56000,
        48000,
        44100,
        40000,
        32000,
        24000,
        22050,
        16000,
        11025,
        8000,
        0
};

static void
uaudio_chan_fill_info(struct uaudio_softc *sc, struct usb_device *udev)
{
        uint32_t rate = uaudio_default_rate;
        uint8_t z;
        uint8_t bits = uaudio_default_bits;
        uint8_t y;
        uint8_t channels = uaudio_default_channels;
        uint8_t channels_max;
        uint8_t x;

        bits -= (bits % 8);
        if ((bits == 0) || (bits > UAUDIO_BITS_MAX)) {
                /* set a valid value */
                bits = UAUDIO_BITS_MAX;
        }

        if (channels > UAUDIO_CHANNELS_MAX)
                channels = UAUDIO_CHANNELS_MAX;
        switch (usbd_get_speed(udev)) {
        case USB_SPEED_LOW:
        case USB_SPEED_FULL:
                /*
                 * Due to high bandwidth usage and problems
                 * with HIGH-speed split transactions we
                 * disable surround setups on FULL-speed USB
                 * by default
                 */
                channels_max = 4;
                /* more channels on request */
                if (channels > channels_max)
                        channels_max = channels;
                break;
        default:
                channels_max = UAUDIO_CHANNELS_MAX;
                break;
        }
        if (channels == 0)
                channels = channels_max;

        /* try to search for a valid config */

        for (x = channels; x; x--) {
                for (y = bits; y; y -= 8) {
                        /* try user defined rate, if any */
                        if (rate != 0)
                                uaudio_chan_fill_info_sub(sc, udev, rate, x, y);

                        /* try find a matching rate, if any */
                        for (z = 0; uaudio_rate_list[z]; z++) {
                                if (uaudio_rate_list[z] != rate)
                                        uaudio_chan_fill_info_sub(sc, udev,
                                            uaudio_rate_list[z], x, y);
                        }

                        /* after default value in first round, proceed with max bits */
                        if (y == bits)
                                y = UAUDIO_BITS_MAX + 8;
                        /* skip default value subsequently */
                        if (y == (bits + 8))
                                y -= 8;
                }

                /* after default value in first round, proceed with max channels */
                if (x == channels)
                        x = channels_max + 1;
                /* skip default value subsequently */
                if (x == (channels + 1))
                        x--;
        }
}

static void
uaudio_chan_play_sync_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct uaudio_chan *ch = usbd_xfer_softc(xfer);
        struct usb_page_cache *pc;
        uint64_t sample_rate;
        uint8_t buf[4];
        uint64_t temp;
        unsigned i;
        int len;
        int actlen;
        int nframes;

        usbd_xfer_status(xfer, &actlen, NULL, NULL, &nframes);

        i = uaudio_get_child_index_by_chan(ch->priv_sc, ch);

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:

                DPRINTFN(6, "transferred %d bytes\n", actlen);

                if (nframes == 0)
                        break;
                len = usbd_xfer_frame_len(xfer, 0);
                if (len == 0)
                        break;
                if (len > sizeof(buf))
                        len = sizeof(buf);

                memset(buf, 0, sizeof(buf));

                pc = usbd_xfer_get_frame(xfer, 0);
                usbd_copy_out(pc, 0, buf, len);

                temp = UGETDW(buf);

                DPRINTF("Value = 0x%08x\n", (int)temp);

                /* auto-detect SYNC format */

                if (len == 4)
                        temp &= 0x0fffffff;

                /* check for no data */

                if (temp == 0)
                        break;

                temp *= 125ULL;

                sample_rate = ch->usb_alt[ch->cur_alt].sample_rate;

                /* auto adjust */
                while (temp < (sample_rate - (sample_rate / 4)))
                        temp *= 2;

                while (temp > (sample_rate + (sample_rate / 2)))
                        temp /= 2;

                DPRINTF("Comparing %d Hz :: %d Hz\n",
                    (int)temp, (int)sample_rate);

                /*
                 * Use feedback value as fallback when there is no
                 * recording channel:
                 */
                if (ch->priv_sc->sc_rec_chan[i].num_alt == 0) {
                        int32_t jitter_max = howmany(sample_rate, 16000);

                        /*
                         * Range check the jitter values to avoid
                         * bogus sample rate adjustments. The expected
                         * deviation should not be more than 1Hz per
                         * second. The USB v2.0 specification also
                         * mandates this requirement. Refer to chapter
                         * 5.12.4.2 about feedback.
                         */
                        ch->jitter_curr = temp - sample_rate;
                        if (ch->jitter_curr > jitter_max)
                                ch->jitter_curr = jitter_max;
                        else if (ch->jitter_curr < -jitter_max)
                                ch->jitter_curr = -jitter_max;
                }
                ch->feedback_rate = temp;
                break;

        case USB_ST_SETUP:
                /*
                 * Check if the recording stream can be used as a
                 * source of jitter information to save some
                 * isochronous bandwidth:
                 */
                if (ch->priv_sc->sc_rec_chan[i].num_alt != 0 &&
                    uaudio_debug == 0)
                        break;
                usbd_xfer_set_frames(xfer, 1);
                usbd_xfer_set_frame_len(xfer, 0, usbd_xfer_max_framelen(xfer));
                usbd_transfer_submit(xfer);
                break;

        default:                        /* Error */
                break;
        }
}

static int
uaudio_chan_is_async(struct uaudio_chan *ch, uint8_t alt)
{
        uint8_t attr = ch->usb_alt[alt].p_ed1->bmAttributes;
        return (UE_GET_ISO_TYPE(attr) == UE_ISO_ASYNC);
}

static void
uaudio_chan_play_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct uaudio_chan *ch = usbd_xfer_softc(xfer);
        struct uaudio_chan *ch_rec;
        struct usb_page_cache *pc;
        uint32_t mfl;
        uint32_t total;
        uint32_t blockcount;
        uint32_t n;
        uint32_t offset;
        unsigned i;
        int sample_size;
        int actlen;
        int sumlen;

        if (ch->running == 0 || ch->start == ch->end) {
                DPRINTF("not running or no buffer!\n");
                return;
        }

        i = uaudio_get_child_index_by_chan(ch->priv_sc, ch);

        /* check if there is a valid record channel */
        ch_rec = ch->priv_sc->sc_rec_chan + i;

        if (ch_rec->num_alt == 0)
                ch_rec = NULL;

        usbd_xfer_status(xfer, &actlen, &sumlen, NULL, NULL);

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_SETUP:
tr_setup:
                if (ch_rec != NULL) {
                        /*
                         * NOTE: The play and record callbacks are
                         * executed from the same USB thread and
                         * locking the record channel mutex here is
                         * not needed. This avoids a LOR situation.
                         */

                        /* reset receive jitter counters */
                        ch_rec->jitter_curr = 0;
                        ch_rec->jitter_rem = 0;
                }

                /* reset transmit jitter counters */
                ch->jitter_curr = 0;
                ch->jitter_rem = 0;

                /* FALLTHROUGH */
        case USB_ST_TRANSFERRED:
                if (actlen < sumlen) {
                        DPRINTF("short transfer, "
                            "%d of %d bytes\n", actlen, sumlen);
                }
                chn_intr(ch->pcm_ch);

                /*
                 * Check for asynchronous playback endpoint and that
                 * the playback endpoint is properly configured:
                 */
                if (ch_rec != NULL &&
                    uaudio_chan_is_async(ch, ch->cur_alt) != 0) {
                        uint32_t rec_alt = ch_rec->cur_alt;
                        if (rec_alt < ch_rec->num_alt) {
                                int64_t tx_jitter;
                                int64_t rx_rate;
                                /*
                                 * NOTE: The play and record callbacks
                                 * are executed from the same USB
                                 * thread and locking the record
                                 * channel mutex here is not needed.
                                 * This avoids a LOR situation.
                                 */

                                /* translate receive jitter into transmit jitter */
                                tx_jitter = ch->usb_alt[ch->cur_alt].sample_rate;
                                tx_jitter = (tx_jitter * ch_rec->jitter_curr) +
                                    ch->jitter_rem;

                                /* reset receive jitter counters */
                                ch_rec->jitter_curr = 0;
                                ch_rec->jitter_rem = 0;
                
                                /* compute exact number of transmit jitter samples */
                                rx_rate = ch_rec->usb_alt[rec_alt].sample_rate;
                                ch->jitter_curr += tx_jitter / rx_rate;
                                ch->jitter_rem = tx_jitter % rx_rate;
                        }
                }

                /* start the SYNC transfer one time per second, if any */
                ch->intr_counter += ch->intr_frames;
                if (ch->intr_counter >= ch->frames_per_second) {
                        ch->intr_counter -= ch->frames_per_second;
                        usbd_transfer_start(ch->xfer[UAUDIO_NCHANBUFS]);
                }

                mfl = usbd_xfer_max_framelen(xfer);

                if (ch->bytes_per_frame[1] > mfl) {
                        DPRINTF("bytes per transfer, %d, "
                            "exceeds maximum, %d!\n",
                            ch->bytes_per_frame[1],
                            mfl);
                        break;
                }

                blockcount = ch->intr_frames;

                /* setup number of frames */
                usbd_xfer_set_frames(xfer, blockcount);

                /* get sample size */
                sample_size = ch->usb_alt[ch->cur_alt].sample_size;

                /* reset total length */
                total = 0;

                /* setup frame lengths */
                for (n = 0; n != blockcount; n++) {
                        uint32_t frame_len;

                        ch->sample_curr += ch->sample_rem;
                        if (ch->sample_curr >= ch->frames_per_second) {
                                ch->sample_curr -= ch->frames_per_second;
                                frame_len = ch->bytes_per_frame[1];
                        } else {
                                frame_len = ch->bytes_per_frame[0];
                        }

                        /* handle free running clock case */
                        if (ch->jitter_curr > 0 &&
                            (frame_len + sample_size) <= mfl) {
                                DPRINTFN(6, "sending one sample more\n");
                                ch->jitter_curr--;
                                frame_len += sample_size;
                        } else if (ch->jitter_curr < 0 &&
                            frame_len >= sample_size) {
                                DPRINTFN(6, "sending one sample less\n");
                                ch->jitter_curr++;
                                frame_len -= sample_size;
                        }
                        usbd_xfer_set_frame_len(xfer, n, frame_len);
                        total += frame_len;
                }

                DPRINTFN(6, "transferring %d bytes\n", total);

                offset = 0;

                pc = usbd_xfer_get_frame(xfer, 0);
                while (total > 0) {
                        n = (ch->end - ch->cur);
                        if (n > total)
                                n = total;

                        usbd_copy_in(pc, offset, ch->cur, n);

                        total -= n;
                        ch->cur += n;
                        offset += n;

                        if (ch->cur >= ch->end)
                                ch->cur = ch->start;
                }
                usbd_transfer_submit(xfer);
                break;

        default:                        /* Error */
                if (error != USB_ERR_CANCELLED)
                        goto tr_setup;
                break;
        }
}

static void
uaudio_chan_record_sync_callback(struct usb_xfer *xfer, usb_error_t error)
{
        /* TODO */
}

static void
uaudio_chan_record_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct uaudio_chan *ch = usbd_xfer_softc(xfer);
        struct usb_page_cache *pc;
        uint32_t offset0;
        uint32_t mfl;
        int m;
        int n;
        int len;
        int actlen;
        int nframes;
        int expected_bytes;
        int sample_size;

        if (ch->start == ch->end) {
                DPRINTF("no buffer!\n");
                return;
        }

        usbd_xfer_status(xfer, &actlen, NULL, NULL, &nframes);
        mfl = usbd_xfer_max_framelen(xfer);

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:

                offset0 = 0;
                pc = usbd_xfer_get_frame(xfer, 0);

                /* try to compute the number of expected bytes */
                ch->sample_curr += (ch->sample_rem * ch->intr_frames);

                /* compute number of expected bytes */
                expected_bytes = (ch->intr_frames * ch->bytes_per_frame[0]) +
                    ((ch->sample_curr / ch->frames_per_second) *
                    (ch->bytes_per_frame[1] - ch->bytes_per_frame[0]));

                /* keep remainder */
                ch->sample_curr %= ch->frames_per_second;

                /* get current sample size */
                sample_size = ch->usb_alt[ch->cur_alt].sample_size;

                for (n = 0; n != nframes; n++) {
                        uint32_t offset1 = offset0;

                        len = usbd_xfer_frame_len(xfer, n);

                        /* make sure we only receive complete samples */
                        len = len - (len % sample_size);

                        /* subtract bytes received from expected payload */
                        expected_bytes -= len;

                        /* don't receive data when not ready */
                        if (ch->running == 0 || ch->cur_alt != ch->set_alt)
                                continue;

                        /* fill ring buffer with samples, if any */
                        while (len > 0) {
                                m = (ch->end - ch->cur);

                                if (m > len)
                                        m = len;

                                usbd_copy_out(pc, offset1, ch->cur, m);

                                len -= m;
                                offset1 += m;
                                ch->cur += m;

                                if (ch->cur >= ch->end)
                                        ch->cur = ch->start;
                        }

                        offset0 += mfl;
                }

                /* update current jitter */
                ch->jitter_curr -= (expected_bytes / sample_size);

                /* don't allow a huge amount of jitter to accumulate */
                nframes = 2 * ch->intr_frames;

                /* range check current jitter */
                if (ch->jitter_curr < -nframes)
                        ch->jitter_curr = -nframes;
                else if (ch->jitter_curr > nframes)
                        ch->jitter_curr = nframes;

                DPRINTFN(6, "transferred %d bytes, jitter %d samples\n",
                    actlen, ch->jitter_curr);

                if (ch->running != 0)
                        chn_intr(ch->pcm_ch);

        case USB_ST_SETUP:
tr_setup:
                nframes = ch->intr_frames;

                usbd_xfer_set_frames(xfer, nframes);
                for (n = 0; n != nframes; n++)
                        usbd_xfer_set_frame_len(xfer, n, mfl);

                usbd_transfer_submit(xfer);
                break;

        default:                        /* Error */
                if (error != USB_ERR_CANCELLED)
                        goto tr_setup;
                break;
        }
}

void   *
uaudio_chan_init(struct uaudio_chan *ch, struct snd_dbuf *b,
    struct pcm_channel *c, int dir)
{
        uint32_t buf_size;
        uint8_t x;

        /* store mutex and PCM channel */

        ch->pcm_ch = c;
        mtx_init(&ch->lock, "uaudio_chan lock", NULL, MTX_DEF);

        /* compute worst case buffer */

        buf_size = 0;
        for (x = 0; x != ch->num_alt; x++) {
                uint32_t temp = uaudio_max_buffer_size(ch, x);
                if (temp > buf_size)
                        buf_size = temp;
        }

        /* allow double buffering */
        buf_size *= 2;

        DPRINTF("Worst case buffer is %d bytes\n", (int)buf_size);

        ch->buf = malloc(buf_size, M_DEVBUF, M_WAITOK | M_ZERO);
        if (sndbuf_setup(b, ch->buf, buf_size) != 0)
                goto error;

        ch->start = ch->buf;
        ch->end = ch->buf + buf_size;
        ch->cur = ch->buf;
        ch->pcm_buf = b;
        ch->max_buf = buf_size;

        return (ch);

error:
        uaudio_chan_free(ch);
        return (NULL);
}

int
uaudio_chan_free(struct uaudio_chan *ch)
{
        free(ch->buf, M_DEVBUF);
        ch->buf = NULL;
        usbd_transfer_unsetup(ch->xfer, UAUDIO_NCHANBUFS + 1);
        mtx_destroy(&ch->lock);

        ch->num_alt = 0;

        return (0);
}

int
uaudio_chan_set_param_blocksize(struct uaudio_chan *ch, uint32_t blocksize)
{
        uint32_t temp = 2 * uaudio_get_buffer_size(ch, ch->set_alt);
        sndbuf_setup(ch->pcm_buf, ch->buf, temp);
        return (temp / 2);
}

int
uaudio_chan_set_param_fragments(struct uaudio_chan *ch, uint32_t blocksize,
    uint32_t blockcount)
{
        return (1);
}

int
uaudio_chan_set_param_speed(struct uaudio_chan *ch, uint32_t speed)
{
        struct uaudio_softc *sc;
        uint8_t x, y;

        sc = ch->priv_sc;

        for (x = 0, y = 1; y < ch->num_alt; y++) {
                /* prefer sample rate closer to and greater than requested */
                if ((ch->usb_alt[x].sample_rate < speed &&
                    ch->usb_alt[x].sample_rate < ch->usb_alt[y].sample_rate) ||
                    (speed <= ch->usb_alt[y].sample_rate &&
                    ch->usb_alt[y].sample_rate < ch->usb_alt[x].sample_rate))
                        x = y;
        }

        usb_proc_explore_lock(sc->sc_udev);
        ch->set_alt = x;
        usb_proc_explore_unlock(sc->sc_udev);

        DPRINTF("Selecting alt %d\n", (int)x);

        return (ch->usb_alt[x].sample_rate);
}

int
uaudio_chan_getptr(struct uaudio_chan *ch)
{
        return (ch->cur - ch->start);
}

struct pcmchan_caps *
uaudio_chan_getcaps(struct uaudio_chan *ch)
{
        return (&ch->pcm_cap);
}

static struct pcmchan_matrix uaudio_chan_matrix_swap_2_0 = {
        .id = SND_CHN_MATRIX_DRV,
        .channels = 2,
        .ext = 0,
        .map = {
                /* Right */
                [0] = {
                        .type = SND_CHN_T_FR,
                        .members =
                            SND_CHN_T_MASK_FR | SND_CHN_T_MASK_FC |
                            SND_CHN_T_MASK_LF | SND_CHN_T_MASK_BR |
                            SND_CHN_T_MASK_BC | SND_CHN_T_MASK_SR
                },
                /* Left */
                [1] = {
                        .type = SND_CHN_T_FL,
                        .members =
                            SND_CHN_T_MASK_FL | SND_CHN_T_MASK_FC |
                            SND_CHN_T_MASK_LF | SND_CHN_T_MASK_BL |
                            SND_CHN_T_MASK_BC | SND_CHN_T_MASK_SL
                },
                [2] = {
                        .type = SND_CHN_T_MAX,
                        .members = 0
                }
        },
        .mask = SND_CHN_T_MASK_FR | SND_CHN_T_MASK_FL,
        .offset = {  1,  0, -1, -1, -1, -1, -1, -1, -1,
                    -1, -1, -1, -1, -1, -1, -1, -1, -1  }
};

struct pcmchan_matrix *
uaudio_chan_getmatrix(struct uaudio_chan *ch, uint32_t format)
{
        struct uaudio_softc *sc;

        sc = ch->priv_sc;

        if (sc != NULL && sc->sc_uq_audio_swap_lr != 0 &&
            AFMT_CHANNEL(format) == 2)
                return (&uaudio_chan_matrix_swap_2_0);

        return (feeder_matrix_format_map(format));
}

int
uaudio_chan_set_param_format(struct uaudio_chan *ch, uint32_t format)
{
        DPRINTF("Selecting format 0x%08x\n", (unsigned int)format);
        return (0);
}

static void
uaudio_chan_reconfigure(struct uaudio_chan *ch, uint8_t operation)
{
        struct uaudio_softc *sc = ch->priv_sc;

        /* Check for shutdown. */
        if (ch->operation == CHAN_OP_DRAIN)
                return;

        /* Set next operation. */
        ch->operation = operation;

        /*
         * Because changing the alternate setting modifies the USB
         * configuration, this part must be executed from the USB
         * explore process.
         */
        (void)usb_proc_explore_msignal(sc->sc_udev,
            &sc->sc_config_msg[0], &sc->sc_config_msg[1]);
}

static int
uaudio_chan_need_both(struct uaudio_chan *pchan, struct uaudio_chan *rchan)
{
        return (pchan->num_alt > 0 &&
            pchan->running != 0 &&
            uaudio_chan_is_async(pchan, pchan->set_alt) != 0 &&
            rchan->num_alt > 0 &&
            rchan->running == 0);
}

static int
uaudio_chan_need_none(struct uaudio_chan *pchan, struct uaudio_chan *rchan)
{
        return (pchan->num_alt > 0 &&
            pchan->running == 0 &&
            rchan->num_alt > 0 &&
            rchan->running == 0);
}

void
uaudio_chan_start(struct uaudio_chan *ch)
{
        struct uaudio_softc *sc = ch->priv_sc;
        unsigned i = uaudio_get_child_index_by_chan(sc, ch);

        /* make operation atomic */
        usb_proc_explore_lock(sc->sc_udev);

        /* check if not running */
        if (ch->running == 0) {
                uint32_t temp;

                /* get current buffer size */
                temp = 2 * uaudio_get_buffer_size(ch, ch->set_alt);

                /* set running flag */
                ch->running = 1;

                /* ensure the hardware buffer is reset */
                ch->start = ch->buf;
                ch->end = ch->buf + temp;
                ch->cur = ch->buf;

                if (uaudio_chan_need_both(
                    &sc->sc_play_chan[i],
                    &sc->sc_rec_chan[i])) {
                        /*
                         * Start both endpoints because of need for
                         * jitter information:
                         */
                        uaudio_chan_reconfigure(&sc->sc_rec_chan[i], CHAN_OP_START);
                        uaudio_chan_reconfigure(&sc->sc_play_chan[i], CHAN_OP_START);
                } else {
                        uaudio_chan_reconfigure(ch, CHAN_OP_START);
                }
        }

        /* exit atomic operation */
        usb_proc_explore_unlock(sc->sc_udev);
}

void
uaudio_chan_stop(struct uaudio_chan *ch)
{
        struct uaudio_softc *sc = ch->priv_sc;
        unsigned i = uaudio_get_child_index_by_chan(sc, ch);

        /* make operation atomic */
        usb_proc_explore_lock(sc->sc_udev);

        /* check if running */
        if (ch->running != 0) {
                /* clear running flag */
                ch->running = 0;

                if (uaudio_chan_need_both(
                    &sc->sc_play_chan[i],
                    &sc->sc_rec_chan[i])) {
                        /*
                         * Leave the endpoints running because we need
                         * information about jitter!
                         */
                } else if (uaudio_chan_need_none(
                    &sc->sc_play_chan[i],
                    &sc->sc_rec_chan[i])) {
                        /*
                         * Stop both endpoints in case the one was used for
                         * jitter information:
                         */
                        uaudio_chan_reconfigure(&sc->sc_rec_chan[i], CHAN_OP_STOP);
                        uaudio_chan_reconfigure(&sc->sc_play_chan[i], CHAN_OP_STOP);
                } else {
                        uaudio_chan_reconfigure(ch, CHAN_OP_STOP);
                }
        }

        /* exit atomic operation */
        usb_proc_explore_unlock(sc->sc_udev);
}

/*========================================================================*
 * AC - Audio Controller - routines
 *========================================================================*/

static int
uaudio_mixer_sysctl_handler(SYSCTL_HANDLER_ARGS)
{
        struct uaudio_softc *sc;
        struct uaudio_mixer_node *pmc;
        int hint;
        int error;
        int temp = 0;
        int chan = 0;

        sc = (struct uaudio_softc *)oidp->oid_arg1;
        hint = oidp->oid_arg2;

        if (sc->sc_child[0].mixer_lock == NULL)
                return (ENXIO);

        /* lookup mixer node */

        mtx_lock(sc->sc_child[0].mixer_lock);
        for (pmc = sc->sc_mixer_root; pmc != NULL; pmc = pmc->next) {
                for (chan = 0; chan != (int)pmc->nchan; chan++) {
                        if (pmc->wValue[chan] != -1 &&
                            pmc->wValue[chan] == hint) {
                                temp = pmc->wData[chan];
                                goto found;
                        }
                }
        }
found:
        mtx_unlock(sc->sc_child[0].mixer_lock);

        error = sysctl_handle_int(oidp, &temp, 0, req);
        if (error != 0 || req->newptr == NULL)
                return (error);

        /* update mixer value */

        mtx_lock(sc->sc_child[0].mixer_lock);
        if (pmc != NULL &&
            temp >= pmc->minval &&
            temp <= pmc->maxval) {
                pmc->wData[chan] = temp;
                pmc->update[(chan / 8)] |= (1 << (chan % 8));

                /* start the transfer, if not already started */
                usbd_transfer_start(sc->sc_mixer_xfer[0]);
        }
        mtx_unlock(sc->sc_child[0].mixer_lock);

        return (0);
}

static void
uaudio_mixer_ctl_free(struct uaudio_softc *sc)
{
        struct uaudio_mixer_node *p_mc;

        while ((p_mc = sc->sc_mixer_root) != NULL) {
                sc->sc_mixer_root = p_mc->next;
                free(p_mc, M_USBDEV);
        }
}

static void
uaudio_mixer_register_sysctl(struct uaudio_softc *sc, device_t dev,
    unsigned index)
{
        struct uaudio_mixer_node *pmc;
        struct sysctl_oid *mixer_tree;
        struct sysctl_oid *control_tree;
        char buf[32];
        int chan;
        int n;

        if (index != 0)
                return;

        mixer_tree = SYSCTL_ADD_NODE(device_get_sysctl_ctx(dev),
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO, "mixer",
            CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, "");

        if (mixer_tree == NULL)
                return;

        for (n = 0, pmc = sc->sc_mixer_root; pmc != NULL;
            pmc = pmc->next, n++) {
                for (chan = 0; chan < pmc->nchan; chan++) {
                        if (pmc->nchan > 1) {
                                snprintf(buf, sizeof(buf), "%s_%d_%d",
                                    pmc->name, n, chan);
                        } else {
                                snprintf(buf, sizeof(buf), "%s_%d",
                                    pmc->name, n);
                        }

                        control_tree = SYSCTL_ADD_NODE(device_get_sysctl_ctx(dev),
                            SYSCTL_CHILDREN(mixer_tree), OID_AUTO, buf,
                            CTLFLAG_RD | CTLFLAG_MPSAFE, NULL,
                            "Mixer control nodes");

                        if (control_tree == NULL)
                                continue;

                        SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
                            SYSCTL_CHILDREN(control_tree),
                            OID_AUTO, "val",
                            CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE,
                            sc, pmc->wValue[chan],
                            uaudio_mixer_sysctl_handler, "I", "Current value");

                        SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
                            SYSCTL_CHILDREN(control_tree),
                            OID_AUTO, "min", CTLFLAG_RD, 0, pmc->minval,
                            "Minimum value");

                        SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
                            SYSCTL_CHILDREN(control_tree),
                            OID_AUTO, "max", CTLFLAG_RD, 0, pmc->maxval,
                            "Maximum value");

                        SYSCTL_ADD_STRING(device_get_sysctl_ctx(dev),
                            SYSCTL_CHILDREN(control_tree),
                            OID_AUTO, "desc", CTLFLAG_RD, pmc->desc, 0,
                            "Description");
                }
        }
}

/* M-Audio FastTrack Ultra Mixer Description */
/* Origin: Linux USB Audio driver */
static void
uaudio_mixer_controls_create_ftu(struct uaudio_softc *sc)
{
        int chx;
        int chy;

        memset(&MIX(sc), 0, sizeof(MIX(sc)));
        MIX(sc).wIndex = MAKE_WORD(6, sc->sc_mixer_iface_no);
        MIX(sc).wValue[0] = MAKE_WORD(8, 0);
        MIX(sc).type = MIX_UNSIGNED_16;
        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;
        MIX(sc).name = "effect";
        MIX(sc).minval = 0;
        MIX(sc).maxval = 7;
        MIX(sc).mul = 7;
        MIX(sc).nchan = 1;
        MIX(sc).update[0] = 1;
        strlcpy(MIX(sc).desc, "Room1,2,3,Hall1,2,Plate,Delay,Echo", sizeof(MIX(sc).desc));
        uaudio_mixer_add_ctl_sub(sc, &MIX(sc));

        memset(&MIX(sc), 0, sizeof(MIX(sc)));
        MIX(sc).wIndex = MAKE_WORD(5, sc->sc_mixer_iface_no);

        for (chx = 0; chx != 8; chx++) {
                for (chy = 0; chy != 8; chy++) {
                        MIX(sc).wValue[0] = MAKE_WORD(chx + 1, chy + 1);
                        MIX(sc).type = MIX_SIGNED_16;
                        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;
                        MIX(sc).name = "mix_rec";
                        MIX(sc).nchan = 1;
                        MIX(sc).update[0] = 1;
                        MIX(sc).val_default = 0;
                        snprintf(MIX(sc).desc, sizeof(MIX(sc).desc),
                            "AIn%d - Out%d Record Volume", chy + 1, chx + 1);

                        uaudio_mixer_add_ctl(sc, &MIX(sc));

                        MIX(sc).wValue[0] = MAKE_WORD(chx + 1, chy + 1 + 8);
                        MIX(sc).type = MIX_SIGNED_16;
                        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;
                        MIX(sc).name = "mix_play";
                        MIX(sc).nchan = 1;
                        MIX(sc).update[0] = 1;
                        MIX(sc).val_default = (chx == chy) ? 2 : 0;
                        snprintf(MIX(sc).desc, sizeof(MIX(sc).desc),
                            "DIn%d - Out%d Playback Volume", chy + 1, chx + 1);

                        uaudio_mixer_add_ctl(sc, &MIX(sc));
                }
        }

        memset(&MIX(sc), 0, sizeof(MIX(sc)));
        MIX(sc).wIndex = MAKE_WORD(6, sc->sc_mixer_iface_no);
        MIX(sc).wValue[0] = MAKE_WORD(2, 0);
        MIX(sc).type = MIX_SIGNED_8;
        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;
        MIX(sc).name = "effect_vol";
        MIX(sc).nchan = 1;
        MIX(sc).update[0] = 1;
        MIX(sc).minval = 0;
        MIX(sc).maxval = 0x7f;
        MIX(sc).mul = 0x7f;
        MIX(sc).nchan = 1;
        MIX(sc).update[0] = 1;
        strlcpy(MIX(sc).desc, "Effect Volume", sizeof(MIX(sc).desc));
        uaudio_mixer_add_ctl_sub(sc, &MIX(sc));

        memset(&MIX(sc), 0, sizeof(MIX(sc)));
        MIX(sc).wIndex = MAKE_WORD(6, sc->sc_mixer_iface_no);
        MIX(sc).wValue[0] = MAKE_WORD(3, 0);
        MIX(sc).type = MIX_SIGNED_16;
        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;
        MIX(sc).name = "effect_dur";
        MIX(sc).nchan = 1;
        MIX(sc).update[0] = 1;
        MIX(sc).minval = 0;
        MIX(sc).maxval = 0x7f00;
        MIX(sc).mul = 0x7f00;
        MIX(sc).nchan = 1;
        MIX(sc).update[0] = 1;
        strlcpy(MIX(sc).desc, "Effect Duration", sizeof(MIX(sc).desc));
        uaudio_mixer_add_ctl_sub(sc, &MIX(sc));

        memset(&MIX(sc), 0, sizeof(MIX(sc)));
        MIX(sc).wIndex = MAKE_WORD(6, sc->sc_mixer_iface_no);
        MIX(sc).wValue[0] = MAKE_WORD(4, 0);
        MIX(sc).type = MIX_SIGNED_8;
        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;
        MIX(sc).name = "effect_fb";
        MIX(sc).nchan = 1;
        MIX(sc).update[0] = 1;
        MIX(sc).minval = 0;
        MIX(sc).maxval = 0x7f;
        MIX(sc).mul = 0x7f;
        MIX(sc).nchan = 1;
        MIX(sc).update[0] = 1;
        strlcpy(MIX(sc).desc, "Effect Feedback Volume", sizeof(MIX(sc).desc));
        uaudio_mixer_add_ctl_sub(sc, &MIX(sc));

        memset(&MIX(sc), 0, sizeof(MIX(sc)));
        MIX(sc).wIndex = MAKE_WORD(7, sc->sc_mixer_iface_no);
        for (chy = 0; chy != 4; chy++) {
                MIX(sc).wValue[0] = MAKE_WORD(7, chy + 1);
                MIX(sc).type = MIX_SIGNED_16;
                MIX(sc).ctl = SOUND_MIXER_NRDEVICES;
                MIX(sc).name = "effect_ret";
                MIX(sc).nchan = 1;
                MIX(sc).update[0] = 1;
                snprintf(MIX(sc).desc, sizeof(MIX(sc).desc),
                    "Effect Return %d Volume", chy + 1);

                uaudio_mixer_add_ctl(sc, &MIX(sc));
        }

        memset(&MIX(sc), 0, sizeof(MIX(sc)));
        MIX(sc).wIndex = MAKE_WORD(5, sc->sc_mixer_iface_no);

        for (chy = 0; chy != 8; chy++) {
                MIX(sc).wValue[0] = MAKE_WORD(9, chy + 1);
                MIX(sc).type = MIX_SIGNED_16;
                MIX(sc).ctl = SOUND_MIXER_NRDEVICES;
                MIX(sc).name = "effect_send";
                MIX(sc).nchan = 1;
                MIX(sc).update[0] = 1;
                snprintf(MIX(sc).desc, sizeof(MIX(sc).desc),
                    "Effect Send AIn%d Volume", chy + 1);

                uaudio_mixer_add_ctl(sc, &MIX(sc));

                MIX(sc).wValue[0] = MAKE_WORD(9, chy + 1 + 8);
                MIX(sc).type = MIX_SIGNED_16;
                MIX(sc).ctl = SOUND_MIXER_NRDEVICES;
                MIX(sc).name = "effect_send";
                MIX(sc).nchan = 1;
                MIX(sc).update[0] = 1;
                snprintf(MIX(sc).desc, sizeof(MIX(sc).desc),
                    "Effect Send DIn%d Volume", chy + 1);

                uaudio_mixer_add_ctl(sc, &MIX(sc));
        }
}

static void
uaudio_mixer_reload_all(struct uaudio_softc *sc)
{
        struct uaudio_mixer_node *pmc;
        int chan;

        if (sc->sc_child[0].mixer_lock == NULL)
                return;

        mtx_lock(sc->sc_child[0].mixer_lock);
        for (pmc = sc->sc_mixer_root; pmc != NULL; pmc = pmc->next) {
                /* use reset defaults for non-oss controlled settings */
                if (pmc->ctl == SOUND_MIXER_NRDEVICES)
                        continue;
                for (chan = 0; chan < pmc->nchan; chan++)
                        pmc->update[chan / 8] |= (1 << (chan % 8));
        }
        usbd_transfer_start(sc->sc_mixer_xfer[0]);

        /* start HID volume keys, if any */
        usbd_transfer_start(sc->sc_hid.xfer[0]);
        mtx_unlock(sc->sc_child[0].mixer_lock);
}

static void
uaudio_mixer_add_ctl_sub(struct uaudio_softc *sc, struct uaudio_mixer_node *mc)
{
        struct uaudio_mixer_node *p_mc_new =
            malloc(sizeof(*p_mc_new), M_USBDEV, M_WAITOK);
        int ch;

        memcpy(p_mc_new, mc, sizeof(*p_mc_new));
        p_mc_new->next = sc->sc_mixer_root;
        sc->sc_mixer_root = p_mc_new;
        sc->sc_mixer_count++;

        /* set default value for all channels */
        for (ch = 0; ch < p_mc_new->nchan; ch++) {
                switch (p_mc_new->val_default) {
                case 1:
                        /* 50% */
                        p_mc_new->wData[ch] = (p_mc_new->maxval + p_mc_new->minval) / 2;
                        break;
                case 2:
                        /* 100% */
                        p_mc_new->wData[ch] = p_mc_new->maxval;
                        break;
                default:
                        /* 0% */
                        p_mc_new->wData[ch] = p_mc_new->minval;
                        break;
                }
        }
}

static void
uaudio_mixer_add_ctl(struct uaudio_softc *sc, struct uaudio_mixer_node *mc)
{
        int32_t res;

        DPRINTF("adding %d\n", mc->ctl);

        if (mc->type == MIX_ON_OFF) {
                mc->minval = 0;
                mc->maxval = 1;
        } else if (mc->type == MIX_SELECTOR) {
        } else {
                /* determine min and max values */

                mc->minval = uaudio_mixer_get(sc->sc_udev,
                    sc->sc_audio_rev, GET_MIN, mc);
                mc->maxval = uaudio_mixer_get(sc->sc_udev,
                    sc->sc_audio_rev, GET_MAX, mc);

                /* check if max and min was swapped */

                if (mc->maxval < mc->minval) {
                        res = mc->maxval;
                        mc->maxval = mc->minval;
                        mc->minval = res;
                }

                /* compute value range */
                mc->mul = mc->maxval - mc->minval;
                if (mc->mul == 0)
                        mc->mul = 1;

                /* compute value alignment */
                res = uaudio_mixer_get(sc->sc_udev,
                    sc->sc_audio_rev, GET_RES, mc);

                DPRINTF("Resolution = %d\n", (int)res);
        }

        uaudio_mixer_add_ctl_sub(sc, mc);

#ifdef USB_DEBUG
        if (uaudio_debug > 2) {
                uint8_t i;

                for (i = 0; i < mc->nchan; i++) {
                        DPRINTF("[mix] wValue=%04x\n", mc->wValue[0]);
                }
                DPRINTF("[mix] wIndex=%04x type=%d ctl='%d' "
                    "min=%d max=%d\n",
                    mc->wIndex, mc->type, mc->ctl,
                    mc->minval, mc->maxval);
        }
#endif
}

static void
uaudio_mixer_add_mixer(struct uaudio_softc *sc,
    const struct uaudio_terminal_node *iot, int id)
{
        const struct usb_audio_mixer_unit_0 *d0 = iot[id].u.mu_v1;
        const struct usb_audio_mixer_unit_1 *d1;

        uint32_t bno;                   /* bit number */
        uint32_t p;                     /* bit number accumulator */
        uint32_t mo;                    /* matching outputs */
        uint32_t mc;                    /* matching channels */
        uint32_t ichs;                  /* input channels */
        uint32_t ochs;                  /* output channels */
        uint32_t c;
        uint32_t chs;                   /* channels */
        uint32_t i;
        uint32_t o;

        DPRINTFN(3, "bUnitId=%d bNrInPins=%d\n",
            d0->bUnitId, d0->bNrInPins);

        /* compute the number of input channels */

        ichs = 0;
        for (i = 0; i < d0->bNrInPins; i++) {
                ichs += uaudio_mixer_get_cluster(
                    d0->baSourceId[i], iot).bNrChannels;
        }

        d1 = (const void *)(d0->baSourceId + d0->bNrInPins);

        /* and the number of output channels */

        ochs = d1->bNrChannels;

        DPRINTFN(3, "ichs=%d ochs=%d\n", ichs, ochs);

        memset(&MIX(sc), 0, sizeof(MIX(sc)));

        MIX(sc).wIndex = MAKE_WORD(d0->bUnitId, sc->sc_mixer_iface_no);
        MIX(sc).type = MIX_SIGNED_16;

        if (uaudio_mixer_verify_desc(d0, ((ichs * ochs) + 7) / 8) == NULL)
                return;

        for (p = i = 0; i < d0->bNrInPins; i++) {
                chs = uaudio_mixer_get_cluster(
                    d0->baSourceId[i], iot).bNrChannels;
                mc = 0;
                for (c = 0; c < chs; c++) {
                        mo = 0;
                        for (o = 0; o < ochs; o++) {
                                bno = ((p + c) * ochs) + o;
                                if (BIT_TEST(d1->bmControls, bno))
                                        mo++;
                        }
                        if (mo == 1)
                                mc++;
                }
                if ((mc == chs) && (chs <= MIX_MAX_CHAN)) {
                        /* repeat bit-scan */

                        mc = 0;
                        for (c = 0; c < chs; c++) {
                                for (o = 0; o < ochs; o++) {
                                        bno = ((p + c) * ochs) + o;
                                        if (BIT_TEST(d1->bmControls, bno))
                                                MIX(sc).wValue[mc++] = MAKE_WORD(p + c + 1, o + 1);
                                }
                        }
                        MIX(sc).nchan = chs;
                        uaudio_mixer_add_ctl(sc, &MIX(sc));
                }
                p += chs;
        }
}

static void
uaudio20_mixer_add_mixer(struct uaudio_softc *sc,
    const struct uaudio_terminal_node *iot, int id)
{
        const struct usb_audio20_mixer_unit_0 *d0 = iot[id].u.mu_v2;
        const struct usb_audio20_mixer_unit_1 *d1;

        uint32_t bno;                   /* bit number */
        uint32_t p;                     /* bit number accumulator */
        uint32_t mo;                    /* matching outputs */
        uint32_t mc;                    /* matching channels */
        uint32_t ichs;                  /* input channels */
        uint32_t ochs;                  /* output channels */
        uint32_t c;
        uint32_t chs;                   /* channels */
        uint32_t i;
        uint32_t o;

        DPRINTFN(3, "bUnitId=%d bNrInPins=%d\n",
            d0->bUnitId, d0->bNrInPins);

        /* compute the number of input channels */

        ichs = 0;
        for (i = 0; i < d0->bNrInPins; i++) {
                ichs += uaudio20_mixer_get_cluster(
                    d0->baSourceId[i], iot).bNrChannels;
        }

        d1 = (const void *)(d0->baSourceId + d0->bNrInPins);

        /* and the number of output channels */

        ochs = d1->bNrChannels;

        DPRINTFN(3, "ichs=%d ochs=%d\n", ichs, ochs);

        memset(&MIX(sc), 0, sizeof(MIX(sc)));

        MIX(sc).wIndex = MAKE_WORD(d0->bUnitId, sc->sc_mixer_iface_no);
        MIX(sc).type = MIX_SIGNED_16;

        if (uaudio20_mixer_verify_desc(d0, ((ichs * ochs) + 7) / 8) == NULL)
                return;

        for (p = i = 0; i < d0->bNrInPins; i++) {
                chs = uaudio20_mixer_get_cluster(
                    d0->baSourceId[i], iot).bNrChannels;
                mc = 0;
                for (c = 0; c < chs; c++) {
                        mo = 0;
                        for (o = 0; o < ochs; o++) {
                                bno = ((p + c) * ochs) + o;
                                if (BIT_TEST(d1->bmControls, bno))
                                        mo++;
                        }
                        if (mo == 1)
                                mc++;
                }
                if ((mc == chs) && (chs <= MIX_MAX_CHAN)) {
                        /* repeat bit-scan */

                        mc = 0;
                        for (c = 0; c < chs; c++) {
                                for (o = 0; o < ochs; o++) {
                                        bno = ((p + c) * ochs) + o;
                                        if (BIT_TEST(d1->bmControls, bno))
                                                MIX(sc).wValue[mc++] = MAKE_WORD(p + c + 1, o + 1);
                                }
                        }
                        MIX(sc).nchan = chs;
                        uaudio_mixer_add_ctl(sc, &MIX(sc));
                }
                p += chs;
        }
}

static void
uaudio_mixer_check_selectors(struct uaudio_softc *sc)
{
        uint8_t reserve_feature[] = {
            SOUND_MIXER_LINE,
            SOUND_MIXER_LINE1,
            SOUND_MIXER_LINE2,
            SOUND_MIXER_LINE3,
            SOUND_MIXER_DIGITAL1,
            SOUND_MIXER_DIGITAL2,
            SOUND_MIXER_DIGITAL3,
        };
        const uint16_t reserve_max =
            sizeof(reserve_feature) / sizeof(reserve_feature[0]);
        uint16_t i;
        uint16_t j;
        uint16_t k;

        /* remove existing selector types from the reserve */   
        for (i = 0; i < MIX(sc).maxval; i++) {
                if (MIX(sc).slctrtype[i] == SOUND_MIXER_NRDEVICES)
                        continue;
                for (j = 0; j != reserve_max; j++) {
                        if (reserve_feature[j] == MIX(sc).slctrtype[i])
                                reserve_feature[j] = SOUND_MIXER_NRDEVICES;
                }
        }

        /* make sure selector types are not overlapping */
        for (i = 0; i < MIX(sc).maxval; i++) {
                if (MIX(sc).slctrtype[i] == SOUND_MIXER_NRDEVICES)
                        continue;
                for (j = i + 1; j < MIX(sc).maxval; j++) {
                        if (MIX(sc).slctrtype[j] == SOUND_MIXER_NRDEVICES)
                                continue;
                        if (MIX(sc).slctrtype[i] != MIX(sc).slctrtype[j])
                                continue;
                        for (k = 0; k != reserve_max; k++) {
                                if (reserve_feature[k] == SOUND_MIXER_NRDEVICES)
                                        continue;
                                MIX(sc).slctrtype[j] = reserve_feature[k];
                                reserve_feature[k] = SOUND_MIXER_NRDEVICES;
                                break;
                        }
                        if (k == reserve_max) {
                                DPRINTF("Selector type %d is not selectable!\n", j);
                                MIX(sc).slctrtype[j] = SOUND_MIXER_NRDEVICES;
                        }
                }
        }
}

static void
uaudio_mixer_add_selector(struct uaudio_softc *sc,
    const struct uaudio_terminal_node *iot, int id)
{
        const struct usb_audio_selector_unit *d = iot[id].u.su_v1;
        uint16_t i;

        DPRINTFN(3, "bUnitId=%d bNrInPins=%d\n",
            d->bUnitId, d->bNrInPins);

        if (d->bNrInPins == 0)
                return;

        memset(&MIX(sc), 0, sizeof(MIX(sc)));

        MIX(sc).wIndex = MAKE_WORD(d->bUnitId, sc->sc_mixer_iface_no);
        MIX(sc).wValue[0] = MAKE_WORD(0, 0);
        MIX(sc).nchan = 1;
        MIX(sc).type = MIX_SELECTOR;
        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;
        MIX(sc).minval = 1;
        MIX(sc).maxval = d->bNrInPins;
        MIX(sc).name = "selector";

        i = d->baSourceId[d->bNrInPins];
        if (i == 0 ||
            usbd_req_get_string_any(sc->sc_udev, NULL,
            MIX(sc).desc, sizeof(MIX(sc).desc), i) != 0) {
                MIX(sc).desc[0] = 0;
        }

        if (MIX(sc).maxval > MAX_SELECTOR_INPUT_PIN)
                MIX(sc).maxval = MAX_SELECTOR_INPUT_PIN;

        MIX(sc).mul = MIX(sc).maxval - MIX(sc).minval;

        for (i = 0; i < MIX(sc).maxval; i++) {
                MIX(sc).slctrtype[i] =
                    uaudio_mixer_determine_class(&iot[d->baSourceId[i]]);
        }
        for (; i < MAX_SELECTOR_INPUT_PIN; i++)
                MIX(sc).slctrtype[i] = SOUND_MIXER_NRDEVICES;

        uaudio_mixer_check_selectors(sc);
        uaudio_mixer_add_ctl(sc, &MIX(sc));
}

static void
uaudio20_mixer_add_selector(struct uaudio_softc *sc,
    const struct uaudio_terminal_node *iot, int id)
{
        const struct usb_audio20_selector_unit *d = iot[id].u.su_v2;
        uint16_t i;

        DPRINTFN(3, "bUnitId=%d bNrInPins=%d\n",
            d->bUnitId, d->bNrInPins);

        if (d->bNrInPins == 0)
                return;

        memset(&MIX(sc), 0, sizeof(MIX(sc)));

        MIX(sc).wIndex = MAKE_WORD(d->bUnitId, sc->sc_mixer_iface_no);
        MIX(sc).wValue[0] = MAKE_WORD(0, 0);
        MIX(sc).nchan = 1;
        MIX(sc).type = MIX_SELECTOR;
        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;
        MIX(sc).minval = 1;
        MIX(sc).maxval = d->bNrInPins;
        MIX(sc).name = "selector";

        i = d->baSourceId[d->bNrInPins];
        if (i == 0 ||
            usbd_req_get_string_any(sc->sc_udev, NULL,
            MIX(sc).desc, sizeof(MIX(sc).desc), i) != 0) {
                MIX(sc).desc[0] = 0;
        }

        if (MIX(sc).maxval > MAX_SELECTOR_INPUT_PIN)
                MIX(sc).maxval = MAX_SELECTOR_INPUT_PIN;

        MIX(sc).mul = MIX(sc).maxval - MIX(sc).minval;

        for (i = 0; i < MIX(sc).maxval; i++) {
                MIX(sc).slctrtype[i] =
                    uaudio20_mixer_determine_class(&iot[d->baSourceId[i]]);
        }
        for (; i < MAX_SELECTOR_INPUT_PIN; i++)
                MIX(sc).slctrtype[i] = SOUND_MIXER_NRDEVICES;

        uaudio_mixer_check_selectors(sc);
        uaudio_mixer_add_ctl(sc, &MIX(sc));
}

static uint32_t
uaudio_mixer_feature_get_bmaControls(const struct usb_audio_feature_unit *d,
    uint8_t i)
{
        uint32_t temp = 0;
        uint32_t offset = (i * d->bControlSize);

        if (d->bControlSize > 0) {
                temp |= d->bmaControls[offset];
                if (d->bControlSize > 1) {
                        temp |= d->bmaControls[offset + 1] << 8;
                        if (d->bControlSize > 2) {
                                temp |= d->bmaControls[offset + 2] << 16;
                                if (d->bControlSize > 3) {
                                        temp |= d->bmaControls[offset + 3] << 24;
                                }
                        }
                }
        }
        return (temp);
}

static void
uaudio_mixer_add_feature(struct uaudio_softc *sc,
    const struct uaudio_terminal_node *iot, int id)
{
        const struct usb_audio_feature_unit *d = iot[id].u.fu_v1;
        uint32_t fumask;
        uint32_t mmask;
        uint32_t cmask;
        uint16_t mixernumber;
        uint8_t nchan;
        uint8_t chan;
        uint8_t ctl;
        uint8_t i;

        if (d->bControlSize == 0)
                return;

        memset(&MIX(sc), 0, sizeof(MIX(sc)));

        nchan = (d->bLength - 7) / d->bControlSize;
        mmask = uaudio_mixer_feature_get_bmaControls(d, 0);
        cmask = 0;

        if (nchan == 0)
                return;

        /* figure out what we can control */

        for (chan = 1; chan < nchan; chan++) {
                DPRINTFN(10, "chan=%d mask=%x\n",
                    chan, uaudio_mixer_feature_get_bmaControls(d, chan));

                cmask |= uaudio_mixer_feature_get_bmaControls(d, chan);
        }

        MIX(sc).wIndex = MAKE_WORD(d->bUnitId, sc->sc_mixer_iface_no);

        i = d->bmaControls[nchan * d->bControlSize];
        if (i == 0 ||
            usbd_req_get_string_any(sc->sc_udev, NULL,
            MIX(sc).desc, sizeof(MIX(sc).desc), i) != 0) {
                MIX(sc).desc[0] = 0;
        }

        if (nchan > MIX_MAX_CHAN)
                nchan = MIX_MAX_CHAN;

        for (ctl = 1; ctl <= LOUDNESS_CONTROL; ctl++) {
                fumask = FU_MASK(ctl);

                DPRINTFN(5, "ctl=%d fumask=0x%04x\n",
                    ctl, fumask);

                if (mmask & fumask) {
                        MIX(sc).nchan = 1;
                        MIX(sc).wValue[0] = MAKE_WORD(ctl, 0);
                } else if (cmask & fumask) {
                        MIX(sc).nchan = nchan - 1;
                        for (i = 1; i < nchan; i++) {
                                if (uaudio_mixer_feature_get_bmaControls(d, i) & fumask)
                                        MIX(sc).wValue[i - 1] = MAKE_WORD(ctl, i);
                                else
                                        MIX(sc).wValue[i - 1] = -1;
                        }
                } else {
                        continue;
                }

                mixernumber = uaudio_mixer_determine_class(&iot[id]);

                switch (ctl) {
                case MUTE_CONTROL:
                        MIX(sc).type = MIX_ON_OFF;
                        MIX(sc).ctl = SOUND_MIXER_MUTE;
                        MIX(sc).name = "mute";
                        break;

                case VOLUME_CONTROL:
                        MIX(sc).type = MIX_SIGNED_16;
                        MIX(sc).ctl = mixernumber;
                        MIX(sc).name = "vol";
                        break;

                case BASS_CONTROL:
                        MIX(sc).type = MIX_SIGNED_8;
                        MIX(sc).ctl = SOUND_MIXER_BASS;
                        MIX(sc).name = "bass";
                        break;

                case MID_CONTROL:
                        MIX(sc).type = MIX_SIGNED_8;
                        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;    /* XXXXX */
                        MIX(sc).name = "mid";
                        break;

                case TREBLE_CONTROL:
                        MIX(sc).type = MIX_SIGNED_8;
                        MIX(sc).ctl = SOUND_MIXER_TREBLE;
                        MIX(sc).name = "treble";
                        break;

                case GRAPHIC_EQUALIZER_CONTROL:
                        continue;       /* XXX don't add anything */

                case AGC_CONTROL:
                        MIX(sc).type = MIX_ON_OFF;
                        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;    /* XXXXX */
                        MIX(sc).name = "agc";
                        break;

                case DELAY_CONTROL:
                        MIX(sc).type = MIX_UNSIGNED_16;
                        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;    /* XXXXX */
                        MIX(sc).name = "delay";
                        break;

                case BASS_BOOST_CONTROL:
                        MIX(sc).type = MIX_ON_OFF;
                        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;    /* XXXXX */
                        MIX(sc).name = "boost";
                        break;

                case LOUDNESS_CONTROL:
                        MIX(sc).type = MIX_ON_OFF;
                        MIX(sc).ctl = SOUND_MIXER_LOUD; /* Is this correct ? */
                        MIX(sc).name = "loudness";
                        break;

                default:
                        MIX(sc).type = MIX_UNKNOWN;
                        break;
                }

                if (MIX(sc).type != MIX_UNKNOWN)
                        uaudio_mixer_add_ctl(sc, &MIX(sc));
        }
}

static void
uaudio20_mixer_add_feature(struct uaudio_softc *sc,
    const struct uaudio_terminal_node *iot, int id)
{
        const struct usb_audio20_feature_unit *d = iot[id].u.fu_v2;
        uint32_t ctl;
        uint32_t mmask;
        uint32_t cmask;
        uint16_t mixernumber;
        uint8_t nchan;
        uint8_t chan;
        uint8_t i;
        uint8_t what;

        if (UGETDW(d->bmaControls[0]) == 0)
                return;

        memset(&MIX(sc), 0, sizeof(MIX(sc)));

        nchan = (d->bLength - 6) / 4;
        mmask = UGETDW(d->bmaControls[0]);
        cmask = 0;

        if (nchan == 0)
                return;

        /* figure out what we can control */

        for (chan = 1; chan < nchan; chan++)
                cmask |= UGETDW(d->bmaControls[chan]);

        MIX(sc).wIndex = MAKE_WORD(d->bUnitId, sc->sc_mixer_iface_no);

        i = d->bmaControls[nchan][0];
        if (i == 0 ||
            usbd_req_get_string_any(sc->sc_udev, NULL,
            MIX(sc).desc, sizeof(MIX(sc).desc), i) != 0) {
                MIX(sc).desc[0] = 0;
        }

        if (nchan > MIX_MAX_CHAN)
                nchan = MIX_MAX_CHAN;

        for (ctl = 3; ctl != 0; ctl <<= 2) {
                mixernumber = uaudio20_mixer_determine_class(&iot[id]);

                switch (ctl) {
                case (3 << 0):
                        MIX(sc).type = MIX_ON_OFF;
                        MIX(sc).ctl = SOUND_MIXER_MUTE;
                        MIX(sc).name = "mute";
                        what = MUTE_CONTROL;
                        break;
                case (3 << 2): 
                        MIX(sc).type = MIX_SIGNED_16;
                        MIX(sc).ctl = mixernumber;
                        MIX(sc).name = "vol";
                        what = VOLUME_CONTROL;
                        break;
                case (3 << 4):
                        MIX(sc).type = MIX_SIGNED_8;
                        MIX(sc).ctl = SOUND_MIXER_BASS;
                        MIX(sc).name = "bass";
                        what = BASS_CONTROL;
                        break;
                case (3 << 6):
                        MIX(sc).type = MIX_SIGNED_8;
                        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;    /* XXXXX */
                        MIX(sc).name = "mid";
                        what = MID_CONTROL;
                        break;
                case (3 << 8):
                        MIX(sc).type = MIX_SIGNED_8;
                        MIX(sc).ctl = SOUND_MIXER_TREBLE;
                        MIX(sc).name = "treble";
                        what = TREBLE_CONTROL;
                        break;
                case (3 << 12):
                        MIX(sc).type = MIX_ON_OFF;
                        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;    /* XXXXX */
                        MIX(sc).name = "agc";
                        what = AGC_CONTROL;
                        break;
                case (3 << 14):
                        MIX(sc).type = MIX_UNSIGNED_16;
                        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;    /* XXXXX */
                        MIX(sc).name = "delay";
                        what = DELAY_CONTROL;
                        break;
                case (3 << 16):
                        MIX(sc).type = MIX_ON_OFF;
                        MIX(sc).ctl = SOUND_MIXER_NRDEVICES;    /* XXXXX */
                        MIX(sc).name = "boost";
                        what = BASS_BOOST_CONTROL;
                        break;
                case (3 << 18):
                        MIX(sc).type = MIX_ON_OFF;
                        MIX(sc).ctl = SOUND_MIXER_LOUD; /* Is this correct ? */
                        MIX(sc).name = "loudness";
                        what = LOUDNESS_CONTROL;
                        break;
                case (3 << 20):
                        MIX(sc).type = MIX_SIGNED_16;
                        MIX(sc).ctl = mixernumber;
                        MIX(sc).name = "igain";
                        what = INPUT_GAIN_CONTROL;
                        break;
                case (3 << 22):
                        MIX(sc).type = MIX_SIGNED_16;
                        MIX(sc).ctl = mixernumber;
                        MIX(sc).name = "igainpad";
                        what = INPUT_GAIN_PAD_CONTROL;
                        break;
                default:
                        continue;
                }

                if ((mmask & ctl) == ctl) {
                        MIX(sc).nchan = 1;
                        MIX(sc).wValue[0] = MAKE_WORD(what, 0);
                } else if ((cmask & ctl) == ctl) {
                        MIX(sc).nchan = nchan - 1;
                        for (i = 1; i < nchan; i++) {
                                if ((UGETDW(d->bmaControls[i]) & ctl) == ctl)
                                        MIX(sc).wValue[i - 1] = MAKE_WORD(what, i);
                                else
                                        MIX(sc).wValue[i - 1] = -1;
                        }
                } else {
                        continue;
                }

                if (MIX(sc).type != MIX_UNKNOWN)
                        uaudio_mixer_add_ctl(sc, &MIX(sc));
        }
}

static void
uaudio_mixer_add_processing_updown(struct uaudio_softc *sc,
    const struct uaudio_terminal_node *iot, int id)
{
        const struct usb_audio_processing_unit_0 *d0 = iot[id].u.pu_v1;
        const struct usb_audio_processing_unit_1 *d1 =
            (const void *)(d0->baSourceId + d0->bNrInPins);
        const struct usb_audio_processing_unit_updown *ud =
            (const void *)(d1->bmControls + d1->bControlSize);
        uint8_t i;

        if (uaudio_mixer_verify_desc(d0, sizeof(*ud)) == NULL) {
                return;
        }
        if (uaudio_mixer_verify_desc(d0, sizeof(*ud) + (2 * ud->bNrModes))
            == NULL) {
                return;
        }
        DPRINTFN(3, "bUnitId=%d bNrModes=%d\n",
            d0->bUnitId, ud->bNrModes);

        if (!(d1->bmControls[0] & UA_PROC_MASK(UD_MODE_SELECT_CONTROL))) {
                DPRINTF("no mode select\n");
                return;
        }
        memset(&MIX(sc), 0, sizeof(MIX(sc)));

        MIX(sc).wIndex = MAKE_WORD(d0->bUnitId, sc->sc_mixer_iface_no);
        MIX(sc).nchan = 1;
        MIX(sc).wValue[0] = MAKE_WORD(UD_MODE_SELECT_CONTROL, 0);
        MIX(sc).type = MIX_ON_OFF;              /* XXX */

        for (i = 0; i < ud->bNrModes; i++) {
                DPRINTFN(3, "i=%d bm=0x%x\n", i, UGETW(ud->waModes[i]));
                /* XXX */
        }

        uaudio_mixer_add_ctl(sc, &MIX(sc));
}

static void
uaudio_mixer_add_processing(struct uaudio_softc *sc,
    const struct uaudio_terminal_node *iot, int id)
{
        const struct usb_audio_processing_unit_0 *d0 = iot[id].u.pu_v1;
        const struct usb_audio_processing_unit_1 *d1 =
            (const void *)(d0->baSourceId + d0->bNrInPins);
        uint16_t ptype;

        memset(&MIX(sc), 0, sizeof(MIX(sc)));

        ptype = UGETW(d0->wProcessType);

        DPRINTFN(3, "wProcessType=%d bUnitId=%d "
            "bNrInPins=%d\n", ptype, d0->bUnitId, d0->bNrInPins);

        if (d1->bControlSize == 0) {
                return;
        }
        if (d1->bmControls[0] & UA_PROC_ENABLE_MASK) {
                MIX(sc).wIndex = MAKE_WORD(d0->bUnitId, sc->sc_mixer_iface_no);
                MIX(sc).nchan = 1;
                MIX(sc).wValue[0] = MAKE_WORD(XX_ENABLE_CONTROL, 0);
                MIX(sc).type = MIX_ON_OFF;
                uaudio_mixer_add_ctl(sc, &MIX(sc));
        }
        switch (ptype) {
        case UPDOWNMIX_PROCESS:
                uaudio_mixer_add_processing_updown(sc, iot, id);
                break;

        case DOLBY_PROLOGIC_PROCESS:
        case P3D_STEREO_EXTENDER_PROCESS:
        case REVERBATION_PROCESS:
        case CHORUS_PROCESS:
        case DYN_RANGE_COMP_PROCESS:
        default:
                DPRINTF("unit %d, type=%d is not implemented\n",
                    d0->bUnitId, ptype);
                break;
        }
}

static void
uaudio_mixer_add_extension(struct uaudio_softc *sc,
    const struct uaudio_terminal_node *iot, int id)
{
        const struct usb_audio_extension_unit_0 *d0 = iot[id].u.eu_v1;
        const struct usb_audio_extension_unit_1 *d1 =
            (const void *)(d0->baSourceId + d0->bNrInPins);

        DPRINTFN(3, "bUnitId=%d bNrInPins=%d\n",
            d0->bUnitId, d0->bNrInPins);

        if (sc->sc_uq_au_no_xu) {
                return;
        }
        if (d1->bControlSize == 0) {
                return;
        }
        if (d1->bmControls[0] & UA_EXT_ENABLE_MASK) {
                memset(&MIX(sc), 0, sizeof(MIX(sc)));

                MIX(sc).wIndex = MAKE_WORD(d0->bUnitId, sc->sc_mixer_iface_no);
                MIX(sc).nchan = 1;
                MIX(sc).wValue[0] = MAKE_WORD(UA_EXT_ENABLE, 0);
                MIX(sc).type = MIX_ON_OFF;

                uaudio_mixer_add_ctl(sc, &MIX(sc));
        }
}

static const void *
uaudio_mixer_verify_desc(const void *arg, uint32_t len)
{
        const struct usb_audio_mixer_unit_1 *d1;
        const struct usb_audio_extension_unit_1 *e1;
        const struct usb_audio_processing_unit_1 *u1;

        union {
                const struct usb_descriptor *desc;
                const struct usb_audio_input_terminal *it;
                const struct usb_audio_output_terminal *ot;
                const struct usb_audio_mixer_unit_0 *mu;
                const struct usb_audio_selector_unit *su;
                const struct usb_audio_feature_unit *fu;
                const struct usb_audio_processing_unit_0 *pu;
                const struct usb_audio_extension_unit_0 *eu;
        }     u;

        u.desc = arg;

        if (u.desc == NULL) {
                goto error;
        }
        if (u.desc->bDescriptorType != UDESC_CS_INTERFACE) {
                goto error;
        }
        switch (u.desc->bDescriptorSubtype) {
        case UDESCSUB_AC_INPUT:
                len += sizeof(*u.it);
                break;

        case UDESCSUB_AC_OUTPUT:
                len += sizeof(*u.ot);
                break;

        case UDESCSUB_AC_MIXER:
                len += sizeof(*u.mu);

                if (u.desc->bLength < len) {
                        goto error;
                }
                len += u.mu->bNrInPins;

                if (u.desc->bLength < len) {
                        goto error;
                }
                d1 = (const void *)(u.mu->baSourceId + u.mu->bNrInPins);

                len += sizeof(*d1);
                break;

        case UDESCSUB_AC_SELECTOR:
                len += sizeof(*u.su);

                if (u.desc->bLength < len) {
                        goto error;
                }
                len += u.su->bNrInPins + 1;
                break;

        case UDESCSUB_AC_FEATURE:
                len += sizeof(*u.fu) + 1;

                if (u.desc->bLength < len)
                        goto error;

                len += u.fu->bControlSize;
                break;

        case UDESCSUB_AC_PROCESSING:
                len += sizeof(*u.pu);

                if (u.desc->bLength < len) {
                        goto error;
                }
                len += u.pu->bNrInPins;

                if (u.desc->bLength < len) {
                        goto error;
                }
                u1 = (const void *)(u.pu->baSourceId + u.pu->bNrInPins);

                len += sizeof(*u1);

                if (u.desc->bLength < len) {
                        goto error;
                }
                len += u1->bControlSize;

                break;

        case UDESCSUB_AC_EXTENSION:
                len += sizeof(*u.eu);

                if (u.desc->bLength < len) {
                        goto error;
                }
                len += u.eu->bNrInPins;

                if (u.desc->bLength < len) {
                        goto error;
                }
                e1 = (const void *)(u.eu->baSourceId + u.eu->bNrInPins);

                len += sizeof(*e1);

                if (u.desc->bLength < len) {
                        goto error;
                }
                len += e1->bControlSize;
                break;

        default:
                goto error;
        }

        if (u.desc->bLength < len) {
                goto error;
        }
        return (u.desc);

error:
        if (u.desc) {
                DPRINTF("invalid descriptor, type=%d, "
                    "sub_type=%d, len=%d of %d bytes\n",
                    u.desc->bDescriptorType,
                    u.desc->bDescriptorSubtype,
                    u.desc->bLength, len);
        }
        return (NULL);
}

static const void *
uaudio20_mixer_verify_desc(const void *arg, uint32_t len)
{
        const struct usb_audio20_mixer_unit_1 *d1;
        const struct usb_audio20_extension_unit_1 *e1;
        const struct usb_audio20_processing_unit_1 *u1;
        const struct usb_audio20_clock_selector_unit_1 *c1;

        union {
                const struct usb_descriptor *desc;
                const struct usb_audio20_clock_source_unit *csrc;
                const struct usb_audio20_clock_selector_unit_0 *csel;
                const struct usb_audio20_clock_multiplier_unit *cmul;
                const struct usb_audio20_input_terminal *it;
                const struct usb_audio20_output_terminal *ot;
                const struct usb_audio20_mixer_unit_0 *mu;
                const struct usb_audio20_selector_unit *su;
                const struct usb_audio20_feature_unit *fu;
                const struct usb_audio20_sample_rate_unit *ru;
                const struct usb_audio20_processing_unit_0 *pu;
                const struct usb_audio20_extension_unit_0 *eu;
                const struct usb_audio20_effect_unit *ef;
        }     u;

        u.desc = arg;

        if (u.desc == NULL)
                goto error;

        if (u.desc->bDescriptorType != UDESC_CS_INTERFACE)
                goto error;

        switch (u.desc->bDescriptorSubtype) {
        case UDESCSUB_AC_INPUT:
                len += sizeof(*u.it);
                break;

        case UDESCSUB_AC_OUTPUT:
                len += sizeof(*u.ot);
                break;

        case UDESCSUB_AC_MIXER:
                len += sizeof(*u.mu);

                if (u.desc->bLength < len)
                        goto error;
                len += u.mu->bNrInPins;

                if (u.desc->bLength < len)
                        goto error;

                d1 = (const void *)(u.mu->baSourceId + u.mu->bNrInPins);

                len += sizeof(*d1) + d1->bNrChannels;
                break;

        case UDESCSUB_AC_SELECTOR:
                len += sizeof(*u.su);

                if (u.desc->bLength < len)
                        goto error;

                len += u.su->bNrInPins + 1;
                break;

        case UDESCSUB_AC_FEATURE:
                len += sizeof(*u.fu) + 1;
                break;

        case UDESCSUB_AC_EFFECT:
                len += sizeof(*u.ef) + 4;
                break;

        case UDESCSUB_AC_PROCESSING_V2:
                len += sizeof(*u.pu);

                if (u.desc->bLength < len)
                        goto error;

                len += u.pu->bNrInPins;

                if (u.desc->bLength < len)
                        goto error;

                u1 = (const void *)(u.pu->baSourceId + u.pu->bNrInPins);

                len += sizeof(*u1);
                break;

        case UDESCSUB_AC_EXTENSION_V2:
                len += sizeof(*u.eu);

                if (u.desc->bLength < len)
                        goto error;

                len += u.eu->bNrInPins;

                if (u.desc->bLength < len)
                        goto error;

                e1 = (const void *)(u.eu->baSourceId + u.eu->bNrInPins);

                len += sizeof(*e1);
                break;

        case UDESCSUB_AC_CLOCK_SRC:
                len += sizeof(*u.csrc);
                break;

        case UDESCSUB_AC_CLOCK_SEL:
                len += sizeof(*u.csel);

                if (u.desc->bLength < len)
                        goto error;

                len += u.csel->bNrInPins;

                if (u.desc->bLength < len)
                        goto error;

                c1 = (const void *)(u.csel->baCSourceId + u.csel->bNrInPins);

                len += sizeof(*c1);
                break;

        case UDESCSUB_AC_CLOCK_MUL:
                len += sizeof(*u.cmul);
                break;

        case UDESCSUB_AC_SAMPLE_RT:
                len += sizeof(*u.ru);
                break;

        default:
                goto error;
        }

        if (u.desc->bLength < len)
                goto error;

        return (u.desc);

error:
        if (u.desc) {
                DPRINTF("invalid descriptor, type=%d, "
                    "sub_type=%d, len=%d of %d bytes\n",
                    u.desc->bDescriptorType,
                    u.desc->bDescriptorSubtype,
                    u.desc->bLength, len);
        }
        return (NULL);
}

static struct usb_audio_cluster
uaudio_mixer_get_cluster(uint8_t id, const struct uaudio_terminal_node *iot)
{
        struct usb_audio_cluster r;
        const struct usb_descriptor *dp;
        uint8_t i;

        for (i = 0; i < UAUDIO_RECURSE_LIMIT; i++) {    /* avoid infinite loops */
                dp = iot[id].u.desc;
                if (dp == NULL) {
                        goto error;
                }
                switch (dp->bDescriptorSubtype) {
                case UDESCSUB_AC_INPUT:
                        r.bNrChannels = iot[id].u.it_v1->bNrChannels;
                        r.wChannelConfig[0] = iot[id].u.it_v1->wChannelConfig[0];
                        r.wChannelConfig[1] = iot[id].u.it_v1->wChannelConfig[1];
                        r.iChannelNames = iot[id].u.it_v1->iChannelNames;
                        goto done;

                case UDESCSUB_AC_OUTPUT:
                        id = iot[id].u.ot_v1->bSourceId;
                        break;

                case UDESCSUB_AC_MIXER:
                        r = *(const struct usb_audio_cluster *)
                            &iot[id].u.mu_v1->baSourceId[
                            iot[id].u.mu_v1->bNrInPins];
                        goto done;

                case UDESCSUB_AC_SELECTOR:
                        if (iot[id].u.su_v1->bNrInPins > 0) {
                                /* XXX This is not really right */
                                id = iot[id].u.su_v1->baSourceId[0];
                        }
                        break;

                case UDESCSUB_AC_FEATURE:
                        id = iot[id].u.fu_v1->bSourceId;
                        break;

                case UDESCSUB_AC_PROCESSING:
                        r = *((const struct usb_audio_cluster *)
                            &iot[id].u.pu_v1->baSourceId[
                            iot[id].u.pu_v1->bNrInPins]);
                        goto done;

                case UDESCSUB_AC_EXTENSION:
                        r = *((const struct usb_audio_cluster *)
                            &iot[id].u.eu_v1->baSourceId[
                            iot[id].u.eu_v1->bNrInPins]);
                        goto done;

                default:
                        goto error;
                }
        }
error:
        DPRINTF("bad data\n");
        memset(&r, 0, sizeof(r));
done:
        return (r);
}

static struct usb_audio20_cluster
uaudio20_mixer_get_cluster(uint8_t id, const struct uaudio_terminal_node *iot)
{
        struct usb_audio20_cluster r;
        const struct usb_descriptor *dp;
        uint8_t i;

        for (i = 0; i < UAUDIO_RECURSE_LIMIT; i++) {    /* avoid infinite loops */
                dp = iot[id].u.desc;
                if (dp == NULL)
                        goto error;

                switch (dp->bDescriptorSubtype) {
                case UDESCSUB_AC_INPUT:
                        r.bNrChannels = iot[id].u.it_v2->bNrChannels;
                        r.bmChannelConfig[0] = iot[id].u.it_v2->bmChannelConfig[0];
                        r.bmChannelConfig[1] = iot[id].u.it_v2->bmChannelConfig[1];
                        r.bmChannelConfig[2] = iot[id].u.it_v2->bmChannelConfig[2];
                        r.bmChannelConfig[3] = iot[id].u.it_v2->bmChannelConfig[3];
                        r.iChannelNames = iot[id].u.it_v2->iTerminal;
                        goto done;

                case UDESCSUB_AC_OUTPUT:
                        id = iot[id].u.ot_v2->bSourceId;
                        break;

                case UDESCSUB_AC_MIXER:
                        r = *(const struct usb_audio20_cluster *)
                            &iot[id].u.mu_v2->baSourceId[
                            iot[id].u.mu_v2->bNrInPins];
                        goto done;

                case UDESCSUB_AC_SELECTOR:
                        if (iot[id].u.su_v2->bNrInPins > 0) {
                                /* XXX This is not really right */
                                id = iot[id].u.su_v2->baSourceId[0];
                        }
                        break;

                case UDESCSUB_AC_SAMPLE_RT:
                        id = iot[id].u.ru_v2->bSourceId;
                        break;

                case UDESCSUB_AC_EFFECT:
                        id = iot[id].u.ef_v2->bSourceId;
                        break;

                case UDESCSUB_AC_FEATURE:
                        id = iot[id].u.fu_v2->bSourceId;
                        break;

                case UDESCSUB_AC_PROCESSING_V2:
                        r = *((const struct usb_audio20_cluster *)
                            &iot[id].u.pu_v2->baSourceId[
                            iot[id].u.pu_v2->bNrInPins]);
                        goto done;

                case UDESCSUB_AC_EXTENSION_V2:
                        r = *((const struct usb_audio20_cluster *)
                            &iot[id].u.eu_v2->baSourceId[
                            iot[id].u.eu_v2->bNrInPins]);
                        goto done;

                default:
                        goto error;
                }
        }
error:
        DPRINTF("Bad data!\n");
        memset(&r, 0, sizeof(r));
done:
        return (r);
}

static bool
uaudio_mixer_foreach_input(const struct uaudio_terminal_node *iot, uint8_t *pindex)
{
        uint8_t n;

        n = *pindex;

        while (1) {
                if (!n--)
                        n = iot->usr.id_max;
                if (n == 0)
                        return (false);
                if (iot->usr.bit_input[n / 8] & (1 << (n % 8)))
                        break;
        }
        *pindex = n;
        return (true);
}

static bool
uaudio_mixer_foreach_output(const struct uaudio_terminal_node *iot, uint8_t *pindex)
{
        uint8_t n;

        n = *pindex;

        while (1) {
                if (!n--)
                        n = iot->usr.id_max;
                if (n == 0)
                        return (false);
                if (iot->usr.bit_output[n / 8] & (1 << (n % 8)))
                        break;
        }
        *pindex = n;
        return (true);
}

struct uaudio_tt_to_feature {
        uint16_t terminal_type;
        uint16_t feature;
};

static const struct uaudio_tt_to_feature uaudio_tt_to_feature[] = {
        {UATI_MICROPHONE, SOUND_MIXER_MIC},
        {UATI_DESKMICROPHONE, SOUND_MIXER_MIC},
        {UATI_PERSONALMICROPHONE, SOUND_MIXER_MIC},
        {UATI_OMNIMICROPHONE, SOUND_MIXER_MIC},
        {UATI_MICROPHONEARRAY, SOUND_MIXER_MIC},
        {UATI_PROCMICROPHONEARR, SOUND_MIXER_MIC},

        {UATE_ANALOGCONN, SOUND_MIXER_LINE},
        {UATE_LINECONN, SOUND_MIXER_LINE},
        {UATE_LEGACYCONN, SOUND_MIXER_LINE},

        {UATE_DIGITALAUIFC, SOUND_MIXER_ALTPCM},
        {UATE_SPDIF, SOUND_MIXER_ALTPCM},
        {UATE_1394DA, SOUND_MIXER_ALTPCM},
        {UATE_1394DV, SOUND_MIXER_ALTPCM},

        {UATF_CDPLAYER, SOUND_MIXER_CD},

        {UATF_SYNTHESIZER, SOUND_MIXER_SYNTH},

        {UATF_VIDEODISCAUDIO, SOUND_MIXER_VIDEO},
        {UATF_DVDAUDIO, SOUND_MIXER_VIDEO},
        {UATF_TVTUNERAUDIO, SOUND_MIXER_VIDEO},

        {UATF_RADIORECV, SOUND_MIXER_RADIO},
        {UATF_RADIOXMIT, SOUND_MIXER_RADIO},

        {}      /* END */
};

static uint16_t
uaudio_mixer_get_feature_by_tt(uint16_t terminal_type, uint16_t default_type)
{
        const struct uaudio_tt_to_feature *uat = uaudio_tt_to_feature;
        uint16_t retval;

        if (terminal_type == 0) {
                retval = default_type;
        } else while (1) {
                if (uat->terminal_type == 0) {
                        switch (terminal_type >> 8) {
                        case UATI_UNDEFINED >> 8:
                                retval = SOUND_MIXER_RECLEV;
                                goto done;
                        case UATO_UNDEFINED >> 8:
                                retval = SOUND_MIXER_PCM;
                                goto done;
                        case UATT_UNDEFINED >> 8:
                                retval = SOUND_MIXER_PHONEIN;
                                goto done;
                        default:
                                retval = default_type;
                                goto done;
                        }
                } else if (uat->terminal_type == terminal_type) {
                        retval = uat->feature;
                        goto done;
                }
                uat++;
        }
done:
        DPRINTF("terminal_type=0x%04x RET=%d DEF=%d\n",
            terminal_type, retval, default_type);
        return (retval);
}

static uint16_t
uaudio_mixer_determine_class(const struct uaudio_terminal_node *iot)
{
        const struct uaudio_terminal_node *ptr;
        uint16_t terminal_type_input = 0;
        uint16_t terminal_type_output = 0;
        uint16_t temp;
        uint8_t match = 0;
        uint8_t i;

        for (i = 0; uaudio_mixer_foreach_input(iot, &i); ) {
                ptr = iot->root + i;
                temp = UGETW(ptr->u.it_v1->wTerminalType);

                if (temp == 0)
                        continue;
                else if (temp == UAT_STREAM)
                        match |= 1;
                else if ((temp & 0xFF00) != (UAT_UNDEFINED & 0xff00))
                        terminal_type_input = temp;
        }

        for (i = 0; uaudio_mixer_foreach_output(iot, &i); ) {
                ptr = iot->root + i;
                temp = UGETW(ptr->u.ot_v1->wTerminalType);

                if (temp == 0)
                        continue;
                else if (temp == UAT_STREAM)
                        match |= 2;
                else if ((temp & 0xFF00) != (UAT_UNDEFINED & 0xff00))
                        terminal_type_output = temp;
        }

        DPRINTF("MATCH=%d IN=0x%04x OUT=0x%04x\n",
            match, terminal_type_input, terminal_type_output);

        switch (match) {
        case 0: /* not connected to USB */
                if (terminal_type_output != 0) {
                        return (uaudio_mixer_get_feature_by_tt(
                            terminal_type_output, SOUND_MIXER_MONITOR));
                } else {
                        return (uaudio_mixer_get_feature_by_tt(
                            terminal_type_input, SOUND_MIXER_MONITOR));
                }
        case 3: /* connected to both USB input and USB output */
                return (SOUND_MIXER_IMIX);
        case 2: /* connected to USB output */
                return (uaudio_mixer_get_feature_by_tt(
                    terminal_type_input, SOUND_MIXER_RECLEV));
        case 1: /* connected to USB input */
                return (uaudio_mixer_get_feature_by_tt(
                    terminal_type_output, SOUND_MIXER_PCM));
        default:
                return (SOUND_MIXER_NRDEVICES);
        }
}

static uint16_t
uaudio20_mixer_determine_class(const struct uaudio_terminal_node *iot)
{
        const struct uaudio_terminal_node *ptr;
        uint16_t terminal_type_input = 0;
        uint16_t terminal_type_output = 0;
        uint16_t temp;
        uint8_t match = 0;
        uint8_t i;

        for (i = 0; uaudio_mixer_foreach_input(iot, &i); ) {
                ptr = iot->root + i;
                temp = UGETW(ptr->u.it_v2->wTerminalType);

                if (temp == 0)
                        continue;
                else if (temp == UAT_STREAM)
                        match |= 1;
                else if ((temp & 0xFF00) != (UAT_UNDEFINED & 0xff00))
                        terminal_type_input = temp;
        }

        for (i = 0; uaudio_mixer_foreach_output(iot, &i); ) {
                ptr = iot->root + i;
                temp = UGETW(ptr->u.ot_v2->wTerminalType);

                if (temp == 0)
                        continue;
                else if (temp == UAT_STREAM)
                        match |= 2;
                else if ((temp & 0xFF00) != (UAT_UNDEFINED & 0xff00))
                        terminal_type_output = temp;
        }

        DPRINTF("MATCH=%d IN=0x%04x OUT=0x%04x\n",
            match, terminal_type_input, terminal_type_output);

        switch (match) {
        case 0: /* not connected to USB */
                if (terminal_type_output != 0) {
                        return (uaudio_mixer_get_feature_by_tt(
                            terminal_type_output, SOUND_MIXER_MONITOR));
                } else {
                        return (uaudio_mixer_get_feature_by_tt(
                            terminal_type_input, SOUND_MIXER_MONITOR));
                }
        case 3: /* connected to both USB input and USB output */
                return (SOUND_MIXER_IMIX);
        case 2: /* connected to USB output */
                return (uaudio_mixer_get_feature_by_tt(
                    terminal_type_input, SOUND_MIXER_RECLEV));
        case 1: /* connected to USB input */
                return (uaudio_mixer_get_feature_by_tt(
                    terminal_type_output, SOUND_MIXER_PCM));
        default:
                return (SOUND_MIXER_NRDEVICES);
        }
}

static void
uaudio_mixer_merge_outputs(struct uaudio_search_result *dst,
    const struct uaudio_search_result *src)
{
        const uint8_t max = sizeof(src->bit_output) / sizeof(src->bit_output[0]);
        uint8_t x;

        for (x = 0; x != max; x++)
                dst->bit_output[x] |= src->bit_output[x];
}

static void
uaudio_mixer_find_inputs_sub(struct uaudio_terminal_node *root,
    const uint8_t *p_id, uint8_t n_id,
    struct uaudio_search_result *info)
{
        struct uaudio_terminal_node *iot;
        uint8_t n;
        uint8_t i;

        for (n = 0; n < n_id; n++) {
                i = p_id[n];

                if (info->recurse_level == UAUDIO_RECURSE_LIMIT) {
                        DPRINTF("avoided going into a circle at id=%d!\n", i);
                        return;
                }

                info->recurse_level++;

                iot = (root + i);

                if (iot->u.desc == NULL)
                        continue;

                switch (iot->u.desc->bDescriptorSubtype) {
                case UDESCSUB_AC_INPUT:
                        uaudio_mixer_merge_outputs(&iot->usr, info);
                        info->bit_input[i / 8] |= (1 << (i % 8));
                        break;

                case UDESCSUB_AC_FEATURE:
                        uaudio_mixer_merge_outputs(&iot->usr, info);
                        uaudio_mixer_find_inputs_sub(
                            root, &iot->u.fu_v1->bSourceId, 1, info);
                        break;

                case UDESCSUB_AC_OUTPUT:
                        info->bit_output[i / 8] |= (1 << (i % 8));
                        uaudio_mixer_find_inputs_sub(
                            root, &iot->u.ot_v1->bSourceId, 1, info);
                        info->bit_output[i / 8] &= ~(1 << (i % 8));
                        break;

                case UDESCSUB_AC_MIXER:
                        uaudio_mixer_merge_outputs(&iot->usr, info);
                        uaudio_mixer_find_inputs_sub(
                            root, iot->u.mu_v1->baSourceId,
                            iot->u.mu_v1->bNrInPins, info);
                        break;

                case UDESCSUB_AC_SELECTOR:
                        uaudio_mixer_merge_outputs(&iot->usr, info);
                        uaudio_mixer_find_inputs_sub(
                            root, iot->u.su_v1->baSourceId,
                            iot->u.su_v1->bNrInPins, info);
                        break;

                case UDESCSUB_AC_PROCESSING:
                        uaudio_mixer_merge_outputs(&iot->usr, info);
                        uaudio_mixer_find_inputs_sub(
                            root, iot->u.pu_v1->baSourceId,
                            iot->u.pu_v1->bNrInPins, info);
                        break;

                case UDESCSUB_AC_EXTENSION:
                        uaudio_mixer_merge_outputs(&iot->usr, info);
                        uaudio_mixer_find_inputs_sub(
                            root, iot->u.eu_v1->baSourceId,
                            iot->u.eu_v1->bNrInPins, info);
                        break;

                default:
                        break;
                }
        }
}

static void
uaudio20_mixer_find_inputs_sub(struct uaudio_terminal_node *root,
    const uint8_t *p_id, uint8_t n_id,
    struct uaudio_search_result *info)
{
        struct uaudio_terminal_node *iot;
        uint8_t n;
        uint8_t i;

        for (n = 0; n < n_id; n++) {
                i = p_id[n];

                if (info->recurse_level == UAUDIO_RECURSE_LIMIT) {
                        DPRINTF("avoided going into a circle at id=%d!\n", i);
                        return;
                }

                info->recurse_level++;

                iot = (root + i);

                if (iot->u.desc == NULL)
                        continue;

                switch (iot->u.desc->bDescriptorSubtype) {
                case UDESCSUB_AC_INPUT:
                        uaudio_mixer_merge_outputs(&iot->usr, info);
                        info->bit_input[i / 8] |= (1 << (i % 8));
                        break;

                case UDESCSUB_AC_OUTPUT:
                        info->bit_output[i / 8] |= (1 << (i % 8));
                        uaudio20_mixer_find_inputs_sub(
                            root, &iot->u.ot_v2->bSourceId, 1, info);
                        info->bit_output[i / 8] &= ~(1 << (i % 8));
                        break;

                case UDESCSUB_AC_MIXER:
                        uaudio_mixer_merge_outputs(&iot->usr, info);
                        uaudio20_mixer_find_inputs_sub(
                            root, iot->u.mu_v2->baSourceId,
                            iot->u.mu_v2->bNrInPins, info);
                        break;

                case UDESCSUB_AC_SELECTOR:
                        uaudio_mixer_merge_outputs(&iot->usr, info);
                        uaudio20_mixer_find_inputs_sub(
                            root, iot->u.su_v2->baSourceId,
                            iot->u.su_v2->bNrInPins, info);
                        break;

                case UDESCSUB_AC_SAMPLE_RT:
                        uaudio_mixer_merge_outputs(&iot->usr, info);
                        uaudio20_mixer_find_inputs_sub(
                            root, &iot->u.ru_v2->bSourceId,
                            1, info);
                        break;

                case UDESCSUB_AC_EFFECT:
                        uaudio_mixer_merge_outputs(&iot->usr, info);
                        uaudio20_mixer_find_inputs_sub(
                            root, &iot->u.ef_v2->bSourceId,
                            1, info);
                        break;

                case UDESCSUB_AC_FEATURE:
                        uaudio_mixer_merge_outputs(&iot->usr, info);
                        uaudio20_mixer_find_inputs_sub(
                            root, &iot->u.fu_v2->bSourceId, 1, info);
                        break;

                case UDESCSUB_AC_PROCESSING_V2:
                        uaudio_mixer_merge_outputs(&iot->usr, info);
                        uaudio20_mixer_find_inputs_sub(
                            root, iot->u.pu_v2->baSourceId,
                            iot->u.pu_v2->bNrInPins, info);
                        break;

                case UDESCSUB_AC_EXTENSION_V2:
                        uaudio_mixer_merge_outputs(&iot->usr, info);
                        uaudio20_mixer_find_inputs_sub(
                            root, iot->u.eu_v2->baSourceId,
                            iot->u.eu_v2->bNrInPins, info);
                        break;
                default:
                        break;
                }
        }
}

static void
uaudio20_mixer_find_clocks_sub(struct uaudio_terminal_node *root,
    const uint8_t *p_id, uint8_t n_id,
    struct uaudio_search_result *info)
{
        struct uaudio_terminal_node *iot;
        uint8_t n;
        uint8_t i;
        uint8_t is_last;
        uint8_t id;

top:
        for (n = 0; n < n_id; n++) {
                i = p_id[n];

                if (info->recurse_level == UAUDIO_RECURSE_LIMIT) {
                        DPRINTF("avoided going into a circle at id=%d!\n", i);
                        return;
                }

                info->recurse_level++;

                iot = (root + i);

                if (iot->u.desc == NULL)
                        continue;

                is_last = ((n + 1) == n_id);

                switch (iot->u.desc->bDescriptorSubtype) {
                case UDESCSUB_AC_INPUT:
                        info->is_input = 1;
                        if (is_last) {
                                p_id = &iot->u.it_v2->bCSourceId;
                                n_id = 1;
                                goto top;
                        }
                        uaudio20_mixer_find_clocks_sub(root,
                            &iot->u.it_v2->bCSourceId, 1, info);
                        break;

                case UDESCSUB_AC_OUTPUT:
                        info->is_input = 0;
                        if (is_last) {
                                p_id = &iot->u.ot_v2->bCSourceId;
                                n_id = 1;
                                goto top;
                        }
                        uaudio20_mixer_find_clocks_sub(root,
                            &iot->u.ot_v2->bCSourceId, 1, info);
                        break;

                case UDESCSUB_AC_CLOCK_SEL:
                        if (is_last) {
                                p_id = iot->u.csel_v2->baCSourceId;
                                n_id = iot->u.csel_v2->bNrInPins;
                                goto top;
                        }
                        uaudio20_mixer_find_clocks_sub(root,
                            iot->u.csel_v2->baCSourceId,
                            iot->u.csel_v2->bNrInPins, info);
                        break;

                case UDESCSUB_AC_CLOCK_MUL:
                        if (is_last) {
                                p_id = &iot->u.cmul_v2->bCSourceId;
                                n_id = 1;
                                goto top;
                        }
                        uaudio20_mixer_find_clocks_sub(root,
                            &iot->u.cmul_v2->bCSourceId,
                            1, info);
                        break;

                case UDESCSUB_AC_CLOCK_SRC:

                        id = iot->u.csrc_v2->bClockId;

                        switch (info->is_input) {
                        case 0:
                                info->bit_output[id / 8] |= (1 << (id % 8));
                                break;
                        case 1:
                                info->bit_input[id / 8] |= (1 << (id % 8));
                                break;
                        default:
                                break;
                        }
                        break;

                default:
                        break;
                }
        }
}

static void
uaudio_mixer_fill_info(struct uaudio_softc *sc,
    struct usb_device *udev, void *desc)
{
        const struct usb_audio_control_descriptor *acdp;
        struct usb_config_descriptor *cd = usbd_get_config_descriptor(udev);
        const struct usb_descriptor *dp;
        const struct usb_audio_unit *au;
        struct uaudio_terminal_node *iot = NULL;
        uint16_t wTotalLen;
        uint8_t ID_max = 0;             /* inclusive */
        uint8_t i;

        desc = usb_desc_foreach(cd, desc);

        if (desc == NULL) {
                DPRINTF("no Audio Control header\n");
                goto done;
        }
        acdp = desc;

        if ((acdp->bLength < sizeof(*acdp)) ||
            (acdp->bDescriptorType != UDESC_CS_INTERFACE) ||
            (acdp->bDescriptorSubtype != UDESCSUB_AC_HEADER)) {
                DPRINTF("invalid Audio Control header\n");
                goto done;
        }
        /* "wTotalLen" is allowed to be corrupt */
        wTotalLen = UGETW(acdp->wTotalLength) - acdp->bLength;

        /* get USB audio revision */
        sc->sc_audio_rev = UGETW(acdp->bcdADC);

        DPRINTFN(3, "found AC header, vers=%03x, len=%d\n",
            sc->sc_audio_rev, wTotalLen);

        iot = malloc(sizeof(struct uaudio_terminal_node) * 256, M_TEMP,
            M_WAITOK | M_ZERO);

        while ((desc = usb_desc_foreach(cd, desc))) {
                dp = desc;

                if (dp->bLength > wTotalLen) {
                        break;
                } else {
                        wTotalLen -= dp->bLength;
                }

                if (sc->sc_audio_rev >= UAUDIO_VERSION_30)
                        au = NULL;
                else if (sc->sc_audio_rev >= UAUDIO_VERSION_20)
                        au = uaudio20_mixer_verify_desc(dp, 0);
                else
                        au = uaudio_mixer_verify_desc(dp, 0);

                if (au) {
                        iot[au->bUnitId].u.desc = (const void *)au;
                        if (au->bUnitId > ID_max)
                                ID_max = au->bUnitId;
                }
        }

        DPRINTF("Maximum ID=%d\n", ID_max);

        /*
         * determine sourcing inputs for
         * all nodes in the tree:
         */
        i = ID_max;
        do {
                if (sc->sc_audio_rev >= UAUDIO_VERSION_30) {
                        /* FALLTHROUGH */
                } else if (sc->sc_audio_rev >= UAUDIO_VERSION_20) {
                        uaudio20_mixer_find_inputs_sub(iot,
                            &i, 1, &((iot + i)->usr));

                        sc->sc_mixer_clocks.is_input = 255;
                        sc->sc_mixer_clocks.recurse_level = 0;

                        uaudio20_mixer_find_clocks_sub(iot,
                            &i, 1, &sc->sc_mixer_clocks);
                } else {
                        uaudio_mixer_find_inputs_sub(iot,
                            &i, 1, &((iot + i)->usr));
                }
        } while (i--);

        /* set "id_max" and "root" */

        i = ID_max;
        do {
                (iot + i)->usr.id_max = ID_max;
                (iot + i)->root = iot;
        } while (i--);

        /*
         * Scan the config to create a linked list of "mixer" nodes:
         */

        i = ID_max;
        do {
                dp = iot[i].u.desc;

                if (dp == NULL)
                        continue;

                DPRINTFN(11, "id=%d subtype=%d\n",
                    i, dp->bDescriptorSubtype);

                if (sc->sc_audio_rev >= UAUDIO_VERSION_30) {
                        continue;
                } else if (sc->sc_audio_rev >= UAUDIO_VERSION_20) {
                        switch (dp->bDescriptorSubtype) {
                        case UDESCSUB_AC_HEADER:
                                DPRINTF("unexpected AC header\n");
                                break;

                        case UDESCSUB_AC_INPUT:
                        case UDESCSUB_AC_OUTPUT:
                        case UDESCSUB_AC_PROCESSING_V2:
                        case UDESCSUB_AC_EXTENSION_V2:
                        case UDESCSUB_AC_EFFECT:
                        case UDESCSUB_AC_CLOCK_SRC:
                        case UDESCSUB_AC_CLOCK_SEL:
                        case UDESCSUB_AC_CLOCK_MUL:
                        case UDESCSUB_AC_SAMPLE_RT:
                                break;

                        case UDESCSUB_AC_MIXER:
                                uaudio20_mixer_add_mixer(sc, iot, i);
                                break;

                        case UDESCSUB_AC_SELECTOR:
                                uaudio20_mixer_add_selector(sc, iot, i);
                                break;

                        case UDESCSUB_AC_FEATURE:
                                uaudio20_mixer_add_feature(sc, iot, i);
                                break;

                        default:
                                DPRINTF("bad AC desc subtype=0x%02x\n",
                                    dp->bDescriptorSubtype);
                                break;
                        }
                        continue;
                }

                switch (dp->bDescriptorSubtype) {
                case UDESCSUB_AC_HEADER:
                        DPRINTF("unexpected AC header\n");
                        break;

                case UDESCSUB_AC_INPUT:
                case UDESCSUB_AC_OUTPUT:
                        break;

                case UDESCSUB_AC_MIXER:
                        uaudio_mixer_add_mixer(sc, iot, i);
                        break;

                case UDESCSUB_AC_SELECTOR:
                        uaudio_mixer_add_selector(sc, iot, i);
                        break;

                case UDESCSUB_AC_FEATURE:
                        uaudio_mixer_add_feature(sc, iot, i);
                        break;

                case UDESCSUB_AC_PROCESSING:
                        uaudio_mixer_add_processing(sc, iot, i);
                        break;

                case UDESCSUB_AC_EXTENSION:
                        uaudio_mixer_add_extension(sc, iot, i);
                        break;

                default:
                        DPRINTF("bad AC desc subtype=0x%02x\n",
                            dp->bDescriptorSubtype);
                        break;
                }

        } while (i--);

done:
        free(iot, M_TEMP);
}

static int
uaudio_mixer_get(struct usb_device *udev, uint16_t audio_rev,
    uint8_t what, struct uaudio_mixer_node *mc)
{
        struct usb_device_request req;
        int val;
        uint8_t data[2 + (2 * 3)];
        usb_error_t err;

        if (mc->wValue[0] == -1)
                return (0);

        if (audio_rev >= UAUDIO_VERSION_30)
                return (0);
        else if (audio_rev >= UAUDIO_VERSION_20) {
                if (what == GET_CUR) {
                        req.bRequest = UA20_CS_CUR;
                        USETW(req.wLength, 2);
                } else {
                        req.bRequest = UA20_CS_RANGE;
                        USETW(req.wLength, 8);
                }
        } else {
                uint16_t len = MIX_SIZE(mc->type);

                req.bRequest = what;
                USETW(req.wLength, len);
        }

        req.bmRequestType = UT_READ_CLASS_INTERFACE;
        USETW(req.wValue, mc->wValue[0]);
        USETW(req.wIndex, mc->wIndex);

        memset(data, 0, sizeof(data));

        err = usbd_do_request(udev, NULL, &req, data);
        if (err) {
                DPRINTF("err=%s\n", usbd_errstr(err));
                return (0);
        }

        if (audio_rev >= UAUDIO_VERSION_30) {
                val = 0;
        } else if (audio_rev >= UAUDIO_VERSION_20) {
                switch (what) {
                case GET_CUR:
                        val = (data[0] | (data[1] << 8));
                        break;
                case GET_MIN:
                        val = (data[2] | (data[3] << 8));
                        break;
                case GET_MAX:
                        val = (data[4] | (data[5] << 8));
                        break;
                case GET_RES:
                        val = (data[6] | (data[7] << 8));
                        break;
                default:
                        val = 0;
                        break;
                }
        } else {
                val = (data[0] | (data[1] << 8));
        }

        if (what == GET_CUR || what == GET_MIN || what == GET_MAX)
                val = uaudio_mixer_signext(mc->type, val);

        DPRINTFN(3, "val=%d\n", val);

        return (val);
}

static void
uaudio_mixer_write_cfg_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct usb_device_request req;
        struct uaudio_softc *sc = usbd_xfer_softc(xfer);
        struct uaudio_mixer_node *mc = sc->sc_mixer_curr;
        struct usb_page_cache *pc;
        uint16_t len;
        uint8_t repeat = 1;
        uint8_t update;
        uint8_t chan;
        uint8_t buf[2];

        DPRINTF("\n");

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:
tr_transferred:
        case USB_ST_SETUP:
tr_setup:

                if (mc == NULL) {
                        mc = sc->sc_mixer_root;
                        sc->sc_mixer_curr = mc;
                        sc->sc_mixer_chan = 0;
                        repeat = 0;
                }
                while (mc) {
                        while (sc->sc_mixer_chan < mc->nchan) {
                                chan = sc->sc_mixer_chan;

                                sc->sc_mixer_chan++;

                                update = ((mc->update[chan / 8] & (1 << (chan % 8))) &&
                                    (mc->wValue[chan] != -1));

                                mc->update[chan / 8] &= ~(1 << (chan % 8));

                                if (update) {
                                        req.bmRequestType = UT_WRITE_CLASS_INTERFACE;
                                        USETW(req.wValue, mc->wValue[chan]);
                                        USETW(req.wIndex, mc->wIndex);

                                        if (sc->sc_audio_rev >= UAUDIO_VERSION_30) {
                                                return;
                                        } else if (sc->sc_audio_rev >= UAUDIO_VERSION_20) {
                                                len = 2;
                                                req.bRequest = UA20_CS_CUR;
                                                USETW(req.wLength, len);
                                        } else {
                                                len = MIX_SIZE(mc->type);
                                                req.bRequest = SET_CUR;
                                                USETW(req.wLength, len);
                                        }

                                        buf[0] = (mc->wData[chan] & 0xFF);
                                        buf[1] = (mc->wData[chan] >> 8) & 0xFF;

                                        pc = usbd_xfer_get_frame(xfer, 0);
                                        usbd_copy_in(pc, 0, &req, sizeof(req));
                                        pc = usbd_xfer_get_frame(xfer, 1);
                                        usbd_copy_in(pc, 0, buf, len);

                                        usbd_xfer_set_frame_len(xfer, 0, sizeof(req));
                                        usbd_xfer_set_frame_len(xfer, 1, len);
                                        usbd_xfer_set_frames(xfer, len ? 2 : 1);
                                        usbd_transfer_submit(xfer);
                                        return;
                                }
                        }

                        mc = mc->next;
                        sc->sc_mixer_curr = mc;
                        sc->sc_mixer_chan = 0;
                }

                if (repeat) {
                        goto tr_setup;
                }
                break;

        default:                        /* Error */
                DPRINTF("error=%s\n", usbd_errstr(error));
                if (error == USB_ERR_CANCELLED) {
                        /* do nothing - we are detaching */
                        break;
                }
                goto tr_transferred;
        }
}

static usb_error_t
uaudio_set_speed(struct usb_device *udev, uint8_t endpt, uint32_t speed)
{
        struct usb_device_request req;
        uint8_t data[3];

        DPRINTFN(6, "endpt=%d speed=%u\n", endpt, speed);

        req.bmRequestType = UT_WRITE_CLASS_ENDPOINT;
        req.bRequest = SET_CUR;
        USETW2(req.wValue, SAMPLING_FREQ_CONTROL, 0);
        USETW(req.wIndex, endpt);
        USETW(req.wLength, 3);
        data[0] = speed;
        data[1] = speed >> 8;
        data[2] = speed >> 16;

        return (usbd_do_request(udev, NULL, &req, data));
}

static usb_error_t
uaudio20_set_speed(struct usb_device *udev, uint8_t iface_no,
    uint8_t clockid, uint32_t speed)
{
        struct usb_device_request req;
        uint8_t data[4];

        DPRINTFN(6, "ifaceno=%d clockid=%d speed=%u\n",
            iface_no, clockid, speed);

        req.bmRequestType = UT_WRITE_CLASS_INTERFACE;
        req.bRequest = UA20_CS_CUR;
        USETW2(req.wValue, UA20_CS_SAM_FREQ_CONTROL, 0);
        USETW2(req.wIndex, clockid, iface_no);
        USETW(req.wLength, 4);
        data[0] = speed;
        data[1] = speed >> 8;
        data[2] = speed >> 16;
        data[3] = speed >> 24;

        return (usbd_do_request(udev, NULL, &req, data));
}

static int
uaudio_mixer_signext(uint8_t type, int val)
{
        if (!MIX_UNSIGNED(type)) {
                if (MIX_SIZE(type) == 2) {
                        val = (int16_t)val;
                } else {
                        val = (int8_t)val;
                }
        }
        return (val);
}

static int
uaudio_mixer_bsd2value(struct uaudio_mixer_node *mc, int val)
{
        if (mc->type == MIX_ON_OFF) {
                val = (val != 0);
        } else if (mc->type != MIX_SELECTOR) {
                /* compute actual volume */
                val = (val * mc->mul) / 100;

                /* add lower offset */
                val = val + mc->minval;
        }
        /* make sure we don't write a value out of range */
        if (val > mc->maxval)
                val = mc->maxval;
        else if (val < mc->minval)
                val = mc->minval;

        DPRINTFN(6, "type=0x%03x val=%d min=%d max=%d val=%d\n",
            mc->type, val, mc->minval, mc->maxval, val);
        return (val);
}

static void
uaudio_mixer_ctl_set(struct uaudio_softc *sc, struct uaudio_mixer_node *mc,
    uint8_t chan, int val)
{
        val = uaudio_mixer_bsd2value(mc, val);

        mc->update[chan / 8] |= (1 << (chan % 8));
        mc->wData[chan] = val;

        /* start the transfer, if not already started */

        usbd_transfer_start(sc->sc_mixer_xfer[0]);
}

static void
uaudio_mixer_init(struct uaudio_softc *sc, unsigned index)
{
        struct uaudio_mixer_node *mc;
        int32_t i;

        if (index != 0)
                return;
        for (mc = sc->sc_mixer_root; mc; mc = mc->next) {
                if (mc->ctl != SOUND_MIXER_NRDEVICES) {
                        /*
                         * Set device mask bits. See
                         * /usr/include/machine/soundcard.h
                         */
                        sc->sc_child[index].mix_info |= 1U << mc->ctl;
                }
                if ((mc->ctl == SOUND_MIXER_NRDEVICES) &&
                    (mc->type == MIX_SELECTOR)) {
                        for (i = mc->minval; (i > 0) && (i <= mc->maxval); i++) {
                                if (mc->slctrtype[i - 1] == SOUND_MIXER_NRDEVICES)
                                        continue;
                                sc->sc_child[index].recsrc_info |= 1U << mc->slctrtype[i - 1];
                        }
                }
        }
}

int
uaudio_mixer_init_sub(struct uaudio_softc *sc, struct snd_mixer *m)
{
        unsigned i = uaudio_get_child_index_by_dev(sc, mix_get_dev(m));

        DPRINTF("child=%u\n", i);

        sc->sc_child[i].mixer_lock = mixer_get_lock(m);
        sc->sc_child[i].mixer_dev = m;

        if (i == 0 &&
            usbd_transfer_setup(sc->sc_udev, &sc->sc_mixer_iface_index,
            sc->sc_mixer_xfer, uaudio_mixer_config, 1, sc,
            sc->sc_child[i].mixer_lock)) {
                DPRINTFN(0, "could not allocate USB transfer for mixer!\n");
                return (ENOMEM);
        }

        if (sc->sc_play_chan[i].num_alt > 0 &&
            (sc->sc_child[i].mix_info & SOUND_MASK_VOLUME) == 0) {
                mix_setparentchild(m, SOUND_MIXER_VOLUME, SOUND_MASK_PCM);
                mix_setrealdev(m, SOUND_MIXER_VOLUME, SOUND_MIXER_NONE);
        }
        mix_setdevs(m, sc->sc_child[i].mix_info);
        mix_setrecdevs(m, sc->sc_child[i].recsrc_info);
        return (0);
}

int
uaudio_mixer_uninit_sub(struct uaudio_softc *sc, struct snd_mixer *m)
{
        unsigned index = uaudio_get_child_index_by_dev(sc, mix_get_dev(m));

        DPRINTF("child=%u\n", index);

        if (index == 0)
                usbd_transfer_unsetup(sc->sc_mixer_xfer, 1);

        sc->sc_child[index].mixer_lock = NULL;

        return (0);
}

void
uaudio_mixer_set(struct uaudio_softc *sc, struct snd_mixer *m,
    unsigned type, unsigned left, unsigned right)
{
        unsigned index = uaudio_get_child_index_by_dev(sc, mix_get_dev(m));
        struct uaudio_mixer_node *mc;
        int chan;

        if (index != 0)
                return;
        for (mc = sc->sc_mixer_root; mc != NULL; mc = mc->next) {
                if (mc->ctl == type) {
                        for (chan = 0; chan < mc->nchan; chan++) {
                                uaudio_mixer_ctl_set(sc, mc, chan,
                                    chan == 0 ? left : right);
                        }
                }
        }
}

uint32_t
uaudio_mixer_setrecsrc(struct uaudio_softc *sc, struct snd_mixer *m, uint32_t src)
{
        unsigned index = uaudio_get_child_index_by_dev(sc, mix_get_dev(m));
        struct uaudio_mixer_node *mc;
        uint32_t mask;
        uint32_t temp;
        int32_t i;

        if (index != 0)
                return (0);
        for (mc = sc->sc_mixer_root; mc; mc = mc->next) {
                if ((mc->ctl == SOUND_MIXER_NRDEVICES) &&
                    (mc->type == MIX_SELECTOR)) {
                        /* compute selector mask */

                        mask = 0;
                        for (i = mc->minval; (i > 0) && (i <= mc->maxval); i++)
                                mask |= 1U << mc->slctrtype[i - 1];

                        temp = mask & src;
                        if (temp == 0)
                                continue;

                        /* find the first set bit */
                        temp = (-temp) & temp;

                        /* update "src" */
                        src &= ~mask;
                        src |= temp;

                        for (i = mc->minval; (i > 0) && (i <= mc->maxval); i++) {
                                if (temp != (1U << mc->slctrtype[i - 1]))
                                        continue;
                                uaudio_mixer_ctl_set(sc, mc, 0, i);
                                break;
                        }
                }
        }
        return (src);
}

/*========================================================================*
 * MIDI support routines
 *========================================================================*/

static void
umidi_bulk_read_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct umidi_chan *chan = usbd_xfer_softc(xfer);
        struct umidi_sub_chan *sub;
        struct usb_page_cache *pc;
        uint8_t buf[4];
        uint8_t cmd_len;
        uint8_t cn;
        uint16_t pos;
        int actlen;

        usbd_xfer_status(xfer, &actlen, NULL, NULL, NULL);

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:

                DPRINTF("actlen=%d bytes\n", actlen);

                pos = 0;
                pc = usbd_xfer_get_frame(xfer, 0);

                while (actlen >= 4) {
                        /* copy out the MIDI data */
                        usbd_copy_out(pc, pos, buf, 4);
                        /* command length */
                        cmd_len = umidi_cmd_to_len[buf[0] & 0xF];
                        /* cable number */
                        cn = buf[0] >> 4;
                        /*
                         * Lookup sub-channel. The index is range
                         * checked below.
                         */
                        sub = &chan->sub[cn];

                        if ((cmd_len != 0) && (cn < chan->max_emb_jack) &&
                            (sub->read_open != 0)) {
                                /* Send data to the application */
                                usb_fifo_put_data_linear(
                                    sub->fifo.fp[USB_FIFO_RX],
                                    buf + 1, cmd_len, 1);
                        }
                        actlen -= 4;
                        pos += 4;
                }

        case USB_ST_SETUP:
                DPRINTF("start\n");
tr_setup:
                usbd_xfer_set_frame_len(xfer, 0, usbd_xfer_max_len(xfer));
                usbd_transfer_submit(xfer);
                break;

        default:
                DPRINTF("error=%s\n", usbd_errstr(error));

                if (error != USB_ERR_CANCELLED) {
                        /* try to clear stall first */
                        usbd_xfer_set_stall(xfer);
                        goto tr_setup;
                }
                break;
        }
}

/*
 * The following statemachine, that converts MIDI commands to
 * USB MIDI packets, derives from Linux's usbmidi.c, which
 * was written by "Clemens Ladisch":
 *
 * Returns:
 *    0: No command
 * Else: Command is complete
 */
static uint8_t
umidi_convert_to_usb(struct umidi_sub_chan *sub, uint8_t cn, uint8_t b)
{
        uint8_t p0 = (cn << 4);

        if (b >= 0xf8) {
                sub->temp_0[0] = p0 | 0x0f;
                sub->temp_0[1] = b;
                sub->temp_0[2] = 0;
                sub->temp_0[3] = 0;
                sub->temp_cmd = sub->temp_0;
                return (1);

        } else if (b >= 0xf0) {
                switch (b) {
                case 0xf0:              /* system exclusive begin */
                        sub->temp_1[1] = b;
                        sub->state = UMIDI_ST_SYSEX_1;
                        break;
                case 0xf1:              /* MIDI time code */
                case 0xf3:              /* song select */
                        sub->temp_1[1] = b;
                        sub->state = UMIDI_ST_1PARAM;
                        break;
                case 0xf2:              /* song position pointer */
                        sub->temp_1[1] = b;
                        sub->state = UMIDI_ST_2PARAM_1;
                        break;
                case 0xf4:              /* unknown */
                case 0xf5:              /* unknown */
                        sub->state = UMIDI_ST_UNKNOWN;
                        break;
                case 0xf6:              /* tune request */
                        sub->temp_1[0] = p0 | 0x05;
                        sub->temp_1[1] = 0xf6;
                        sub->temp_1[2] = 0;
                        sub->temp_1[3] = 0;
                        sub->temp_cmd = sub->temp_1;
                        sub->state = UMIDI_ST_UNKNOWN;
                        return (1);

                case 0xf7:              /* system exclusive end */
                        switch (sub->state) {
                        case UMIDI_ST_SYSEX_0:
                                sub->temp_1[0] = p0 | 0x05;
                                sub->temp_1[1] = 0xf7;
                                sub->temp_1[2] = 0;
                                sub->temp_1[3] = 0;
                                sub->temp_cmd = sub->temp_1;
                                sub->state = UMIDI_ST_UNKNOWN;
                                return (1);
                        case UMIDI_ST_SYSEX_1:
                                sub->temp_1[0] = p0 | 0x06;
                                sub->temp_1[2] = 0xf7;
                                sub->temp_1[3] = 0;
                                sub->temp_cmd = sub->temp_1;
                                sub->state = UMIDI_ST_UNKNOWN;
                                return (1);
                        case UMIDI_ST_SYSEX_2:
                                sub->temp_1[0] = p0 | 0x07;
                                sub->temp_1[3] = 0xf7;
                                sub->temp_cmd = sub->temp_1;
                                sub->state = UMIDI_ST_UNKNOWN;
                                return (1);
                        }
                        sub->state = UMIDI_ST_UNKNOWN;
                        break;
                }
        } else if (b >= 0x80) {
                sub->temp_1[1] = b;
                if ((b >= 0xc0) && (b <= 0xdf)) {
                        sub->state = UMIDI_ST_1PARAM;
                } else {
                        sub->state = UMIDI_ST_2PARAM_1;
                }
        } else {                        /* b < 0x80 */
                switch (sub->state) {
                case UMIDI_ST_1PARAM:
                        if (sub->temp_1[1] < 0xf0) {
                                p0 |= sub->temp_1[1] >> 4;
                        } else {
                                p0 |= 0x02;
                                sub->state = UMIDI_ST_UNKNOWN;
                        }
                        sub->temp_1[0] = p0;
                        sub->temp_1[2] = b;
                        sub->temp_1[3] = 0;
                        sub->temp_cmd = sub->temp_1;
                        return (1);
                case UMIDI_ST_2PARAM_1:
                        sub->temp_1[2] = b;
                        sub->state = UMIDI_ST_2PARAM_2;
                        break;
                case UMIDI_ST_2PARAM_2:
                        if (sub->temp_1[1] < 0xf0) {
                                p0 |= sub->temp_1[1] >> 4;
                                sub->state = UMIDI_ST_2PARAM_1;
                        } else {
                                p0 |= 0x03;
                                sub->state = UMIDI_ST_UNKNOWN;
                        }
                        sub->temp_1[0] = p0;
                        sub->temp_1[3] = b;
                        sub->temp_cmd = sub->temp_1;
                        return (1);
                case UMIDI_ST_SYSEX_0:
                        sub->temp_1[1] = b;
                        sub->state = UMIDI_ST_SYSEX_1;
                        break;
                case UMIDI_ST_SYSEX_1:
                        sub->temp_1[2] = b;
                        sub->state = UMIDI_ST_SYSEX_2;
                        break;
                case UMIDI_ST_SYSEX_2:
                        sub->temp_1[0] = p0 | 0x04;
                        sub->temp_1[3] = b;
                        sub->temp_cmd = sub->temp_1;
                        sub->state = UMIDI_ST_SYSEX_0;
                        return (1);
                default:
                        break;
                }
        }
        return (0);
}

static void
umidi_bulk_write_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct umidi_chan *chan = usbd_xfer_softc(xfer);
        struct umidi_sub_chan *sub;
        struct usb_page_cache *pc;
        uint32_t actlen;
        uint16_t nframes;
        uint8_t buf;
        uint8_t start_cable;
        uint8_t tr_any;
        int len;

        usbd_xfer_status(xfer, &len, NULL, NULL, NULL);

        /*
         * NOTE: Some MIDI devices only accept 4 bytes of data per
         * short terminated USB transfer.
         */
        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:
                DPRINTF("actlen=%d bytes\n", len);

        case USB_ST_SETUP:
tr_setup:
                DPRINTF("start\n");

                nframes = 0;    /* reset */
                start_cable = chan->curr_cable;
                tr_any = 0;
                pc = usbd_xfer_get_frame(xfer, 0);

                while (1) {
                        /* round robin de-queueing */

                        sub = &chan->sub[chan->curr_cable];

                        if (sub->write_open) {
                                usb_fifo_get_data_linear(sub->fifo.fp[USB_FIFO_TX],
                                    &buf, 1, &actlen, 0);
                        } else {
                                actlen = 0;
                        }

                        if (actlen) {
                                tr_any = 1;

                                DPRINTF("byte=0x%02x from FIFO %u\n", buf,
                                    (unsigned int)chan->curr_cable);

                                if (umidi_convert_to_usb(sub, chan->curr_cable, buf)) {
                                        DPRINTF("sub=0x%02x 0x%02x 0x%02x 0x%02x\n",
                                            sub->temp_cmd[0], sub->temp_cmd[1],
                                            sub->temp_cmd[2], sub->temp_cmd[3]);

                                        usbd_copy_in(pc, nframes * 4, sub->temp_cmd, 4);

                                        nframes++;

                                        if ((nframes >= UMIDI_TX_FRAMES) || (chan->single_command != 0))
                                                break;
                                } else {
                                        continue;
                                }
                        }

                        chan->curr_cable %= chan->max_emb_jack;

                        if (chan->curr_cable == start_cable) {
                                if (tr_any == 0)
                                        break;
                                tr_any = 0;
                        }
                }

                if (nframes != 0) {
                        DPRINTF("Transferring %d frames\n", (int)nframes);
                        usbd_xfer_set_frame_len(xfer, 0, 4 * nframes);
                        usbd_transfer_submit(xfer);
                }
                break;

        default:                        /* Error */

                DPRINTF("error=%s\n", usbd_errstr(error));

                if (error != USB_ERR_CANCELLED) {
                        /* try to clear stall first */
                        usbd_xfer_set_stall(xfer);
                        goto tr_setup;
                }
                break;
        }
}

static struct umidi_sub_chan *
umidi_sub_by_fifo(struct usb_fifo *fifo)
{
        struct umidi_chan *chan = usb_fifo_softc(fifo);
        struct umidi_sub_chan *sub;
        uint32_t n;

        for (n = 0; n < UMIDI_EMB_JACK_MAX; n++) {
                sub = &chan->sub[n];
                if ((sub->fifo.fp[USB_FIFO_RX] == fifo) ||
                    (sub->fifo.fp[USB_FIFO_TX] == fifo)) {
                        return (sub);
                }
        }

        panic("%s:%d cannot find usb_fifo!\n",
            __FILE__, __LINE__);

        return (NULL);
}

static void
umidi_start_read(struct usb_fifo *fifo)
{
        struct umidi_chan *chan = usb_fifo_softc(fifo);

        usbd_transfer_start(chan->xfer[UMIDI_RX_TRANSFER]);
}

static void
umidi_stop_read(struct usb_fifo *fifo)
{
        struct umidi_chan *chan = usb_fifo_softc(fifo);
        struct umidi_sub_chan *sub = umidi_sub_by_fifo(fifo);

        DPRINTF("\n");

        sub->read_open = 0;

        if (--(chan->read_open_refcount) == 0) {
                /*
                 * XXX don't stop the read transfer here, hence that causes
                 * problems with some MIDI adapters
                 */
                DPRINTF("(stopping read transfer)\n");
        }
}

static void
umidi_start_write(struct usb_fifo *fifo)
{
        struct umidi_chan *chan = usb_fifo_softc(fifo);

        if (chan->xfer[UMIDI_TX_TRANSFER] == NULL) {
                uint8_t buf[1];
                int actlen;
                do {
                        /* dump data */
                        usb_fifo_get_data_linear(fifo, buf, 1, &actlen, 0);
                } while (actlen > 0);
        } else {
                usbd_transfer_start(chan->xfer[UMIDI_TX_TRANSFER]);
        }
}

static void
umidi_stop_write(struct usb_fifo *fifo)
{
        struct umidi_chan *chan = usb_fifo_softc(fifo);
        struct umidi_sub_chan *sub = umidi_sub_by_fifo(fifo);

        DPRINTF("\n");

        sub->write_open = 0;

        if (--(chan->write_open_refcount) == 0) {
                DPRINTF("(stopping write transfer)\n");
                usbd_transfer_stop(chan->xfer[UMIDI_TX_TRANSFER]);
        }
}

static int
umidi_open(struct usb_fifo *fifo, int fflags)
{
        struct umidi_chan *chan = usb_fifo_softc(fifo);
        struct umidi_sub_chan *sub = umidi_sub_by_fifo(fifo);

        if (fflags & FREAD) {
                if (usb_fifo_alloc_buffer(fifo, 4, (1024 / 4))) {
                        return (ENOMEM);
                }
                mtx_lock(&chan->mtx);
                chan->read_open_refcount++;
                sub->read_open = 1;
                mtx_unlock(&chan->mtx);
        }
        if (fflags & FWRITE) {
                if (usb_fifo_alloc_buffer(fifo, 32, (1024 / 32))) {
                        return (ENOMEM);
                }
                /* clear stall first */
                mtx_lock(&chan->mtx);
                chan->write_open_refcount++;
                sub->write_open = 1;

                /* reset */
                sub->state = UMIDI_ST_UNKNOWN;
                mtx_unlock(&chan->mtx);
        }
        return (0);                     /* success */
}

static void
umidi_close(struct usb_fifo *fifo, int fflags)
{
        if (fflags & FREAD) {
                usb_fifo_free_buffer(fifo);
        }
        if (fflags & FWRITE) {
                usb_fifo_free_buffer(fifo);
        }
}

static int
umidi_ioctl(struct usb_fifo *fifo, u_long cmd, void *data,
    int fflags)
{
        return (ENODEV);
}

static void
umidi_init(device_t dev)
{
        struct uaudio_softc *sc = device_get_softc(dev);
        struct umidi_chan *chan = &sc->sc_midi_chan;

        mtx_init(&chan->mtx, "umidi lock", NULL, MTX_DEF | MTX_RECURSE);
}

static struct usb_fifo_methods umidi_fifo_methods = {
        .f_start_read = &umidi_start_read,
        .f_start_write = &umidi_start_write,
        .f_stop_read = &umidi_stop_read,
        .f_stop_write = &umidi_stop_write,
        .f_open = &umidi_open,
        .f_close = &umidi_close,
        .f_ioctl = &umidi_ioctl,
        .basename[0] = "umidi",
};

static int
umidi_attach(device_t dev)
{
        struct uaudio_softc *sc = device_get_softc(dev);
        struct usb_attach_arg *uaa = device_get_ivars(dev);
        struct umidi_chan *chan = &sc->sc_midi_chan;
        struct umidi_sub_chan *sub;
        int unit = device_get_unit(dev);
        int error;
        uint32_t n;

        if (usb_test_quirk(uaa, UQ_SINGLE_CMD_MIDI))
                chan->single_command = 1;

        error = usbd_set_alt_interface_index(sc->sc_udev,
            chan->iface_index, chan->iface_alt_index);
        if (error) {
                DPRINTF("setting of alternate index failed: %s\n",
                    usbd_errstr(error));
                goto detach;
        }
        usbd_set_parent_iface(sc->sc_udev, chan->iface_index,
            sc->sc_mixer_iface_index);

        error = usbd_transfer_setup(uaa->device, &chan->iface_index,
            chan->xfer, umidi_config, UMIDI_N_TRANSFER,
            chan, &chan->mtx);
        if (error) {
                DPRINTF("error=%s\n", usbd_errstr(error));
                goto detach;
        }
        if (chan->xfer[UMIDI_TX_TRANSFER] == NULL &&
            chan->xfer[UMIDI_RX_TRANSFER] == NULL) {
                DPRINTF("no BULK or INTERRUPT MIDI endpoint(s) found\n");
                goto detach;
        }

        /*
         * Some USB MIDI device makers couldn't resist using
         * wMaxPacketSize = 4 for RX and TX BULK endpoints, although
         * that size is an unsupported value for FULL speed BULK
         * endpoints. The same applies to some HIGH speed MIDI devices
         * which are using a wMaxPacketSize different from 512 bytes.
         *
         * Refer to section 5.8.3 in USB 2.0 PDF: Cite: "All Host
         * Controllers are required to have support for 8-, 16-, 32-,
         * and 64-byte maximum packet sizes for full-speed bulk
         * endpoints and 512 bytes for high-speed bulk endpoints."
         */
        if (chan->xfer[UMIDI_TX_TRANSFER] != NULL &&
            usbd_xfer_maxp_was_clamped(chan->xfer[UMIDI_TX_TRANSFER]))
                chan->single_command = 1;

        if (chan->single_command != 0)
                device_printf(dev, "Single command MIDI quirk enabled\n");

        if ((chan->max_emb_jack == 0) ||
            (chan->max_emb_jack > UMIDI_EMB_JACK_MAX)) {
                chan->max_emb_jack = UMIDI_EMB_JACK_MAX;
        }

        for (n = 0; n < chan->max_emb_jack; n++) {
                sub = &chan->sub[n];

                error = usb_fifo_attach(sc->sc_udev, chan, &chan->mtx,
                    &umidi_fifo_methods, &sub->fifo, unit, n,
                    chan->iface_index,
                    UID_ROOT, GID_OPERATOR, 0666);
                if (error) {
                        goto detach;
                }
        }

        mtx_lock(&chan->mtx);

        /*
         * NOTE: At least one device will not work properly unless the
         * BULK IN pipe is open all the time. This might have to do
         * about that the internal queues of the device overflow if we
         * don't read them regularly.
         */
        usbd_transfer_start(chan->xfer[UMIDI_RX_TRANSFER]);

        mtx_unlock(&chan->mtx);

        return (0);                     /* success */

detach:
        return (ENXIO);                 /* failure */
}

static int
umidi_detach(device_t dev)
{
        struct uaudio_softc *sc = device_get_softc(dev);
        struct umidi_chan *chan = &sc->sc_midi_chan;
        uint32_t n;

        for (n = 0; n < UMIDI_EMB_JACK_MAX; n++)
                usb_fifo_detach(&chan->sub[n].fifo);

        mtx_lock(&chan->mtx);

        usbd_transfer_stop(chan->xfer[UMIDI_RX_TRANSFER]);

        mtx_unlock(&chan->mtx);

        usbd_transfer_unsetup(chan->xfer, UMIDI_N_TRANSFER);

        mtx_destroy(&chan->mtx);

        return (0);
}

static void
uaudio_hid_rx_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct uaudio_softc *sc = usbd_xfer_softc(xfer);
        const uint8_t *buffer = usbd_xfer_get_frame_buffer(xfer, 0);
        struct snd_mixer *m;
        uint8_t id;
        int actlen;

        usbd_xfer_status(xfer, &actlen, NULL, NULL, NULL);

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:
                DPRINTF("actlen=%d\n", actlen);

                if (actlen != 0 &&
                    (sc->sc_hid.flags & UAUDIO_HID_HAS_ID)) {
                        id = *buffer;
                        buffer++;
                        actlen--;
                } else {
                        id = 0;
                }

                m = sc->sc_child[0].mixer_dev;

                if ((sc->sc_hid.flags & UAUDIO_HID_HAS_MUTE) &&
                    (sc->sc_hid.mute_id == id) &&
                    hid_get_data(buffer, actlen,
                    &sc->sc_hid.mute_loc)) {
                        DPRINTF("Mute toggle\n");

                        mixer_hwvol_mute_locked(m);
                }

                if ((sc->sc_hid.flags & UAUDIO_HID_HAS_VOLUME_UP) &&
                    (sc->sc_hid.volume_up_id == id) &&
                    hid_get_data(buffer, actlen,
                    &sc->sc_hid.volume_up_loc)) {
                        DPRINTF("Volume Up\n");

                        mixer_hwvol_step_locked(m, 1, 1);
                }

                if ((sc->sc_hid.flags & UAUDIO_HID_HAS_VOLUME_DOWN) &&
                    (sc->sc_hid.volume_down_id == id) &&
                    hid_get_data(buffer, actlen,
                    &sc->sc_hid.volume_down_loc)) {
                        DPRINTF("Volume Down\n");

                        mixer_hwvol_step_locked(m, -1, -1);
                }

        case USB_ST_SETUP:
tr_setup:
                /* check if we can put more data into the FIFO */
                usbd_xfer_set_frame_len(xfer, 0, usbd_xfer_max_len(xfer));
                usbd_transfer_submit(xfer);
                break;

        default:                        /* Error */

                DPRINTF("error=%s\n", usbd_errstr(error));

                if (error != USB_ERR_CANCELLED) {
                        /* try to clear stall first */
                        usbd_xfer_set_stall(xfer);
                        goto tr_setup;
                }
                break;
        }
}

static int
uaudio_hid_attach(struct uaudio_softc *sc,
    struct usb_attach_arg *uaa)
{
        void *d_ptr;
        uint32_t flags;
        uint16_t d_len;
        uint8_t id;
        int error;

        if (!(sc->sc_hid.flags & UAUDIO_HID_VALID))
                return (-1);

        if (sc->sc_child[0].mixer_lock == NULL)
                return (-1);

        /* Get HID descriptor */
        error = usbd_req_get_hid_desc(uaa->device, NULL, &d_ptr,
            &d_len, M_TEMP, sc->sc_hid.iface_index);

        if (error) {
                DPRINTF("error reading report description\n");
                return (-1);
        }

        /* check if there is an ID byte */
        hid_report_size_max(d_ptr, d_len, hid_input, &id);

        if (id != 0)
                sc->sc_hid.flags |= UAUDIO_HID_HAS_ID;

        if (hid_locate(d_ptr, d_len,
            HID_USAGE2(HUP_CONSUMER, 0xE9 /* Volume Increment */),
            hid_input, 0, &sc->sc_hid.volume_up_loc, &flags,
            &sc->sc_hid.volume_up_id)) {
                if (flags & HIO_VARIABLE)
                        sc->sc_hid.flags |= UAUDIO_HID_HAS_VOLUME_UP;
                DPRINTFN(1, "Found Volume Up key\n");
        }

        if (hid_locate(d_ptr, d_len,
            HID_USAGE2(HUP_CONSUMER, 0xEA /* Volume Decrement */),
            hid_input, 0, &sc->sc_hid.volume_down_loc, &flags,
            &sc->sc_hid.volume_down_id)) {
                if (flags & HIO_VARIABLE)
                        sc->sc_hid.flags |= UAUDIO_HID_HAS_VOLUME_DOWN;
                DPRINTFN(1, "Found Volume Down key\n");
        }

        if (hid_locate(d_ptr, d_len,
            HID_USAGE2(HUP_CONSUMER, 0xE2 /* Mute */),
            hid_input, 0, &sc->sc_hid.mute_loc, &flags,
            &sc->sc_hid.mute_id)) {
                if (flags & HIO_VARIABLE)
                        sc->sc_hid.flags |= UAUDIO_HID_HAS_MUTE;
                DPRINTFN(1, "Found Mute key\n");
        }

        free(d_ptr, M_TEMP);

        if (!(sc->sc_hid.flags & (UAUDIO_HID_HAS_VOLUME_UP |
            UAUDIO_HID_HAS_VOLUME_DOWN |
            UAUDIO_HID_HAS_MUTE))) {
                DPRINTFN(1, "Did not find any volume related keys\n");
                return (-1);
        }

        /* prevent the uhid driver from attaching */
        usbd_set_parent_iface(uaa->device, sc->sc_hid.iface_index,
            sc->sc_mixer_iface_index);

        /* allocate USB transfers */
        error = usbd_transfer_setup(uaa->device, &sc->sc_hid.iface_index,
            sc->sc_hid.xfer, uaudio_hid_config, UAUDIO_HID_N_TRANSFER,
            sc, sc->sc_child[0].mixer_lock);
        if (error) {
                DPRINTF("error=%s\n", usbd_errstr(error));
                return (-1);
        }
        return (0);
}

static void
uaudio_hid_detach(struct uaudio_softc *sc)
{
        usbd_transfer_unsetup(sc->sc_hid.xfer, UAUDIO_HID_N_TRANSFER);
}

DRIVER_MODULE_ORDERED(snd_uaudio, uhub, uaudio_driver, NULL, NULL, SI_ORDER_ANY);
MODULE_DEPEND(snd_uaudio, usb, 1, 1, 1);
MODULE_DEPEND(snd_uaudio, sound, SOUND_MINVER, SOUND_PREFVER, SOUND_MAXVER);
MODULE_DEPEND(snd_uaudio, hid, 1, 1, 1);
MODULE_VERSION(snd_uaudio, 1);
USB_PNP_HOST_INFO(uaudio_devs);
USB_PNP_HOST_INFO(uaudio_vendor_midi);