/*-
 * Copyright (c) 2000, 2001 Michael Smith
 * Copyright (c) 2000 BSDi
 * All rights reserved.
 *
 * 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 AUTHOR 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 AUTHOR 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>
#include "opt_acpi.h"
#include <sys/param.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/cpu.h>
#include <sys/kthread.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <sys/reboot.h>
#include <sys/sysctl.h>
#include <sys/unistd.h>
#include <sys/power.h>

#include "cpufreq_if.h"

#include <contrib/dev/acpica/include/acpi.h>
#include <contrib/dev/acpica/include/accommon.h>

#include <dev/acpica/acpivar.h>

/* Hooks for the ACPI CA debugging infrastructure */
#define _COMPONENT      ACPI_THERMAL
ACPI_MODULE_NAME("THERMAL")

#define TZ_ZEROC        2731
#define TZ_KELVTOC(x)   (((x) - TZ_ZEROC) / 10), abs(((x) - TZ_ZEROC) % 10)

#define TZ_NOTIFY_TEMPERATURE   0x80 /* Temperature changed. */
#define TZ_NOTIFY_LEVELS        0x81 /* Cooling levels changed. */
#define TZ_NOTIFY_DEVICES       0x82 /* Device lists changed. */
#define TZ_NOTIFY_CRITICAL      0xcc /* Fake notify that _CRT/_HOT/_CR3 reached. */

/* Check for temperature changes every 10 seconds by default */
#define TZ_POLLRATE     10

/* Make sure the reported temperature is valid for this number of polls. */
#define TZ_VALIDCHECKS  3

/* Notify the user we will be shutting down in one more poll cycle. */
#define TZ_NOTIFYCOUNT  (TZ_VALIDCHECKS - 1)

/* ACPI spec defines this */
#define TZ_NUMLEVELS    10
struct acpi_tz_zone {
    int         ac[TZ_NUMLEVELS];
    ACPI_BUFFER al[TZ_NUMLEVELS];
    int         crt;
    int         hot;
    int         cr3;
    ACPI_BUFFER psl;
    int         psv;
    int         tc1;
    int         tc2;
    int         tsp;
    int         tzp;
};

struct acpi_tz_softc {
    device_t                    tz_dev;
    ACPI_HANDLE                 tz_handle;      /*Thermal zone handle*/
    int                         tz_temperature; /*Current temperature*/
    int                         tz_active;      /*Current active cooling*/
#define TZ_ACTIVE_NONE          -1
#define TZ_ACTIVE_UNKNOWN       -2
    int                         tz_requested;   /*Minimum active cooling*/
    int                         tz_thflags;     /*Current temp-related flags*/
#define TZ_THFLAG_NONE          0
#define TZ_THFLAG_PSV           (1<<0)
#define TZ_THFLAG_CR3           (1<<2)
#define TZ_THFLAG_HOT           (1<<3)
#define TZ_THFLAG_CRT           (1<<4)
    int                         tz_flags;
#define TZ_FLAG_NO_SCP          (1<<0)          /*No _SCP method*/
#define TZ_FLAG_GETPROFILE      (1<<1)          /*Get power_profile in timeout*/
#define TZ_FLAG_GETSETTINGS     (1<<2)          /*Get devs/setpoints*/
    struct timespec             tz_cooling_started;
                                        /*Current cooling starting time*/

    struct sysctl_ctx_list      tz_sysctl_ctx;
    struct sysctl_oid           *tz_sysctl_tree;
    eventhandler_tag            tz_event;

    struct acpi_tz_zone         tz_zone;        /*Thermal zone parameters*/
    int                         tz_validchecks;
    int                         tz_insane_tmp_notified;

    /* passive cooling */
    struct proc                 *tz_cooling_proc;
    int                         tz_cooling_proc_running;
    int                         tz_cooling_enabled;
    int                         tz_cooling_active;
    int                         tz_cooling_updated;
    int                         tz_cooling_saved_freq;
};

#define TZ_ACTIVE_LEVEL(act)    ((act) >= 0 ? (act) : TZ_NUMLEVELS)

#define CPUFREQ_MAX_LEVELS      64 /* XXX cpufreq should export this */

static int      acpi_tz_probe(device_t dev);
static int      acpi_tz_attach(device_t dev);
static int      acpi_tz_establish(struct acpi_tz_softc *sc);
static void     acpi_tz_monitor(void *Context);
static void     acpi_tz_switch_cooler_off(ACPI_OBJECT *obj, void *arg);
static void     acpi_tz_switch_cooler_on(ACPI_OBJECT *obj, void *arg);
static void     acpi_tz_getparam(struct acpi_tz_softc *sc, char *node,
                                 int *data);
static void     acpi_tz_sanity(struct acpi_tz_softc *sc, int *val, char *what);
static int      acpi_tz_active_sysctl(SYSCTL_HANDLER_ARGS);
static int      acpi_tz_cooling_sysctl(SYSCTL_HANDLER_ARGS);
static int      acpi_tz_temp_sysctl(SYSCTL_HANDLER_ARGS);
static int      acpi_tz_passive_sysctl(SYSCTL_HANDLER_ARGS);
static void     acpi_tz_notify_handler(ACPI_HANDLE h, UINT32 notify,
                                       void *context);
static void     acpi_tz_signal(struct acpi_tz_softc *sc, int flags);
static void     acpi_tz_timeout(struct acpi_tz_softc *sc, int flags);
static void     acpi_tz_power_profile(void *arg);
static void     acpi_tz_thread(void *arg);
static int      acpi_tz_cooling_is_available(struct acpi_tz_softc *sc);
static int      acpi_tz_cooling_thread_start(struct acpi_tz_softc *sc);

static device_method_t acpi_tz_methods[] = {
    /* Device interface */
    DEVMETHOD(device_probe,     acpi_tz_probe),
    DEVMETHOD(device_attach,    acpi_tz_attach),

    DEVMETHOD_END
};

static driver_t acpi_tz_driver = {
    "acpi_tz",
    acpi_tz_methods,
    sizeof(struct acpi_tz_softc),
};

static char *acpi_tz_tmp_name = "_TMP";

DRIVER_MODULE(acpi_tz, acpi, acpi_tz_driver, 0, 0);
MODULE_DEPEND(acpi_tz, acpi, 1, 1, 1);

static struct sysctl_ctx_list   acpi_tz_sysctl_ctx;
static struct sysctl_oid        *acpi_tz_sysctl_tree;

/* Minimum cooling run time */
static int                      acpi_tz_min_runtime;
static int                      acpi_tz_polling_rate = TZ_POLLRATE;
static int                      acpi_tz_override;

/* Thermal zone polling thread */
static struct proc              *acpi_tz_proc;
ACPI_LOCK_DECL(thermal, "ACPI thermal zone");

static int                      acpi_tz_cooling_unit = -1;

static int
acpi_tz_probe(device_t dev)
{
    int         result;

    if (acpi_get_type(dev) == ACPI_TYPE_THERMAL && !acpi_disabled("thermal")) {
        device_set_desc(dev, "Thermal Zone");
        result = -10;
    } else
        result = ENXIO;
    return (result);
}

static int
acpi_tz_attach(device_t dev)
{
    struct acpi_tz_softc        *sc;
    struct acpi_softc           *acpi_sc;
    int                         error;
    char                        oidname[16];

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    sc = device_get_softc(dev);
    sc->tz_dev = dev;
    sc->tz_handle = acpi_get_handle(dev);
    sc->tz_requested = TZ_ACTIVE_NONE;
    sc->tz_active = TZ_ACTIVE_UNKNOWN;
    sc->tz_thflags = TZ_THFLAG_NONE;
    sc->tz_cooling_proc = NULL;
    sc->tz_cooling_proc_running = FALSE;
    sc->tz_cooling_active = FALSE;
    sc->tz_cooling_updated = FALSE;
    sc->tz_cooling_enabled = FALSE;

    /*
     * Parse the current state of the thermal zone and build control
     * structures.  We don't need to worry about interference with the
     * control thread since we haven't fully attached this device yet.
     */
    if ((error = acpi_tz_establish(sc)) != 0)
        return (error);

    /*
     * Register for any Notify events sent to this zone.
     */
    AcpiInstallNotifyHandler(sc->tz_handle, ACPI_DEVICE_NOTIFY,
                             acpi_tz_notify_handler, sc);

    /*
     * Create our sysctl nodes.
     *
     * XXX we need a mechanism for adding nodes under ACPI.
     */
    if (device_get_unit(dev) == 0) {
        acpi_sc = acpi_device_get_parent_softc(dev);
        sysctl_ctx_init(&acpi_tz_sysctl_ctx);
        acpi_tz_sysctl_tree = SYSCTL_ADD_NODE(&acpi_tz_sysctl_ctx,
            SYSCTL_CHILDREN(acpi_sc->acpi_sysctl_tree), OID_AUTO, "thermal",
            CTLFLAG_RD | CTLFLAG_MPSAFE, 0, "");
        SYSCTL_ADD_INT(&acpi_tz_sysctl_ctx,
                       SYSCTL_CHILDREN(acpi_tz_sysctl_tree),
                       OID_AUTO, "min_runtime", CTLFLAG_RW,
                       &acpi_tz_min_runtime, 0,
                       "minimum cooling run time in sec");
        SYSCTL_ADD_INT(&acpi_tz_sysctl_ctx,
                       SYSCTL_CHILDREN(acpi_tz_sysctl_tree),
                       OID_AUTO, "polling_rate", CTLFLAG_RW,
                       &acpi_tz_polling_rate, 0, "monitor polling interval in seconds");
        SYSCTL_ADD_INT(&acpi_tz_sysctl_ctx,
                       SYSCTL_CHILDREN(acpi_tz_sysctl_tree), OID_AUTO,
                       "user_override", CTLFLAG_RW, &acpi_tz_override, 0,
                       "allow override of thermal settings");
    }
    sysctl_ctx_init(&sc->tz_sysctl_ctx);
    snprintf(oidname, sizeof(oidname), "tz%d", device_get_unit(dev));
    sc->tz_sysctl_tree = SYSCTL_ADD_NODE_WITH_LABEL(&sc->tz_sysctl_ctx,
        SYSCTL_CHILDREN(acpi_tz_sysctl_tree), OID_AUTO, oidname,
        CTLFLAG_RD | CTLFLAG_MPSAFE, 0, "", "thermal_zone");
    SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
        OID_AUTO, "temperature", CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
        &sc->tz_temperature, 0, sysctl_handle_int, "IK",
        "current thermal zone temperature");
    SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
        OID_AUTO, "active", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, sc,
        0, acpi_tz_active_sysctl, "I", "cooling is active");
    SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
        OID_AUTO, "passive_cooling",
        CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, sc, 0,
        acpi_tz_cooling_sysctl, "I",
        "enable passive (speed reduction) cooling");

    SYSCTL_ADD_INT(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
                   OID_AUTO, "thermal_flags", CTLFLAG_RD,
                   &sc->tz_thflags, 0, "thermal zone flags");
    SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
        OID_AUTO, "_PSV", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, sc,
        offsetof(struct acpi_tz_softc, tz_zone.psv), acpi_tz_temp_sysctl, "IK",
        "passive cooling temp setpoint");
    SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
        OID_AUTO, "_CR3", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, sc,
        offsetof(struct acpi_tz_softc, tz_zone.cr3), acpi_tz_temp_sysctl, "IK",
        "too warm temp setpoint (standby now)");
    SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
        OID_AUTO, "_HOT", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, sc,
        offsetof(struct acpi_tz_softc, tz_zone.hot), acpi_tz_temp_sysctl, "IK",
        "too hot temp setpoint (suspend now)");
    SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
        OID_AUTO, "_CRT", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, sc,
        offsetof(struct acpi_tz_softc, tz_zone.crt), acpi_tz_temp_sysctl, "IK",
        "critical temp setpoint (shutdown now)");
    SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
        OID_AUTO, "_ACx", CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
        &sc->tz_zone.ac, sizeof(sc->tz_zone.ac), sysctl_handle_opaque, "IK",
        "");
    SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
        OID_AUTO, "_TC1", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, sc,
        offsetof(struct acpi_tz_softc, tz_zone.tc1), acpi_tz_passive_sysctl,
        "I", "thermal constant 1 for passive cooling");
    SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
        OID_AUTO, "_TC2", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, sc,
        offsetof(struct acpi_tz_softc, tz_zone.tc2), acpi_tz_passive_sysctl,
        "I", "thermal constant 2 for passive cooling");
    SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
        OID_AUTO, "_TSP", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, sc,
        offsetof(struct acpi_tz_softc, tz_zone.tsp), acpi_tz_passive_sysctl,
        "I", "thermal sampling period for passive cooling");

    /*
     * Register our power profile event handler.
     */
    sc->tz_event = EVENTHANDLER_REGISTER(power_profile_change,
        acpi_tz_power_profile, sc, 0);

    /*
     * Flag the event handler for a manual invocation by our timeout.
     * We defer it like this so that the rest of the subsystem has time
     * to come up.  Don't bother evaluating/printing the temperature at
     * this point; on many systems it'll be bogus until the EC is running.
     */
    sc->tz_flags |= TZ_FLAG_GETPROFILE;

    return_VALUE (0);
}

static void
acpi_tz_startup(void *arg __unused)
{
    struct acpi_tz_softc *sc;
    device_t *devs;
    int devcount, error, i;

    devclass_get_devices(devclass_find("acpi_tz"), &devs, &devcount);
    if (devcount == 0) {
        free(devs, M_TEMP);
        return;
    }

    /*
     * Create thread to service all of the thermal zones.
     */
    error = kproc_create(acpi_tz_thread, NULL, &acpi_tz_proc, RFHIGHPID, 0,
        "acpi_thermal");
    if (error != 0)
        printf("acpi_tz: could not create thread - %d", error);

    /*
     * Create a thread to handle passive cooling for 1st zone which
     * has _PSV, _TSP, _TC1 and _TC2.  Users can enable it for other
     * zones manually for now.
     *
     * XXX We enable only one zone to avoid multiple zones conflict
     * with each other since cpufreq currently sets all CPUs to the
     * given frequency whereas it's possible for different thermal
     * zones to specify independent settings for multiple CPUs.
     */
    for (i = 0; i < devcount; i++) {
        sc = device_get_softc(devs[i]);
        if (acpi_tz_cooling_is_available(sc)) {
            sc->tz_cooling_enabled = TRUE;
            error = acpi_tz_cooling_thread_start(sc);
            if (error != 0) {
                sc->tz_cooling_enabled = FALSE;
                break;
            }
            acpi_tz_cooling_unit = device_get_unit(devs[i]);
            break;
        }
    }
    free(devs, M_TEMP);
}
SYSINIT(acpi_tz, SI_SUB_KICK_SCHEDULER, SI_ORDER_ANY, acpi_tz_startup, NULL);

/*
 * Parse the current state of this thermal zone and set up to use it.
 *
 * Note that we may have previous state, which will have to be discarded.
 */
static int
acpi_tz_establish(struct acpi_tz_softc *sc)
{
    ACPI_OBJECT *obj;
    int         i;
    char        nbuf[8];

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    /* Erase any existing state. */
    for (i = 0; i < TZ_NUMLEVELS; i++)
        if (sc->tz_zone.al[i].Pointer != NULL)
            AcpiOsFree(sc->tz_zone.al[i].Pointer);
    if (sc->tz_zone.psl.Pointer != NULL)
        AcpiOsFree(sc->tz_zone.psl.Pointer);

    /*
     * XXX: We initialize only ACPI_BUFFER to avoid race condition
     * with passive cooling thread which refers psv, tc1, tc2 and tsp.
     */
    bzero(sc->tz_zone.ac, sizeof(sc->tz_zone.ac));
    bzero(sc->tz_zone.al, sizeof(sc->tz_zone.al));
    bzero(&sc->tz_zone.psl, sizeof(sc->tz_zone.psl));

    /* Evaluate thermal zone parameters. */
    for (i = 0; i < TZ_NUMLEVELS; i++) {
        sprintf(nbuf, "_AC%d", i);
        acpi_tz_getparam(sc, nbuf, &sc->tz_zone.ac[i]);
        sprintf(nbuf, "_AL%d", i);
        sc->tz_zone.al[i].Length = ACPI_ALLOCATE_BUFFER;
        sc->tz_zone.al[i].Pointer = NULL;
        AcpiEvaluateObject(sc->tz_handle, nbuf, NULL, &sc->tz_zone.al[i]);
        obj = (ACPI_OBJECT *)sc->tz_zone.al[i].Pointer;
        if (obj != NULL) {
            /* Should be a package containing a list of power objects */
            if (obj->Type != ACPI_TYPE_PACKAGE) {
                device_printf(sc->tz_dev, "%s has unknown type %d, rejecting\n",
                              nbuf, obj->Type);
                return_VALUE (ENXIO);
            }
        }
    }
    acpi_tz_getparam(sc, "_CRT", &sc->tz_zone.crt);
    acpi_tz_getparam(sc, "_HOT", &sc->tz_zone.hot);
    acpi_tz_getparam(sc, "_CR3", &sc->tz_zone.cr3);
    sc->tz_zone.psl.Length = ACPI_ALLOCATE_BUFFER;
    sc->tz_zone.psl.Pointer = NULL;
    AcpiEvaluateObject(sc->tz_handle, "_PSL", NULL, &sc->tz_zone.psl);
    acpi_tz_getparam(sc, "_PSV", &sc->tz_zone.psv);
    acpi_tz_getparam(sc, "_TC1", &sc->tz_zone.tc1);
    acpi_tz_getparam(sc, "_TC2", &sc->tz_zone.tc2);
    acpi_tz_getparam(sc, "_TSP", &sc->tz_zone.tsp);
    acpi_tz_getparam(sc, "_TZP", &sc->tz_zone.tzp);

    /*
     * Sanity-check the values we've been given.
     *
     * XXX what do we do about systems that give us the same value for
     *     more than one of these setpoints?
     */
    acpi_tz_sanity(sc, &sc->tz_zone.crt, "_CRT");
    acpi_tz_sanity(sc, &sc->tz_zone.hot, "_HOT");
    acpi_tz_sanity(sc, &sc->tz_zone.cr3, "_CR3");
    acpi_tz_sanity(sc, &sc->tz_zone.psv, "_PSV");
    for (i = 0; i < TZ_NUMLEVELS; i++)
        acpi_tz_sanity(sc, &sc->tz_zone.ac[i], "_ACx");

    return_VALUE (0);
}

static char *aclevel_string[] = {
    "NONE", "_AC0", "_AC1", "_AC2", "_AC3", "_AC4",
    "_AC5", "_AC6", "_AC7", "_AC8", "_AC9"
};

static __inline const char *
acpi_tz_aclevel_string(int active)
{
    if (active < -1 || active >= TZ_NUMLEVELS)
        return (aclevel_string[0]);

    return (aclevel_string[active + 1]);
}

/*
 * Get the current temperature.
 */
static int
acpi_tz_get_temperature(struct acpi_tz_softc *sc)
{
    int         temp;
    ACPI_STATUS status;

    ACPI_FUNCTION_NAME ("acpi_tz_get_temperature");

    /* Evaluate the thermal zone's _TMP method. */
    status = acpi_GetInteger(sc->tz_handle, acpi_tz_tmp_name, &temp);
    if (ACPI_FAILURE(status)) {
        ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
            "error fetching current temperature -- %s\n",
             AcpiFormatException(status));
        return (FALSE);
    }

    /* Check it for validity. */
    acpi_tz_sanity(sc, &temp, acpi_tz_tmp_name);
    if (temp == -1)
        return (FALSE);

    ACPI_DEBUG_PRINT((ACPI_DB_VALUES, "got %d.%dC\n", TZ_KELVTOC(temp)));
    sc->tz_temperature = temp;
    return (TRUE);
}

/*
 * Evaluate the condition of a thermal zone, take appropriate actions.
 */
static void
acpi_tz_monitor(void *Context)
{
    struct acpi_softc    *acpi_sc;
    struct acpi_tz_softc *sc;
    struct      timespec curtime;
    int         temp;
    int         i;
    int         newactive, newflags;

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    sc = (struct acpi_tz_softc *)Context;

    /* Get the current temperature. */
    if (!acpi_tz_get_temperature(sc)) {
        /* XXX disable zone? go to max cooling? */
        return_VOID;
    }
    temp = sc->tz_temperature;

    /*
     * Work out what we ought to be doing right now.
     *
     * Note that the _ACx levels sort from hot to cold.
     */
    newactive = TZ_ACTIVE_NONE;
    for (i = TZ_NUMLEVELS - 1; i >= 0; i--) {
        if (sc->tz_zone.ac[i] != -1 && temp >= sc->tz_zone.ac[i])
            newactive = i;
    }

    /*
     * We are going to get _ACx level down (colder side), but give a guaranteed
     * minimum cooling run time if requested.
     */
    if (acpi_tz_min_runtime > 0 && sc->tz_active != TZ_ACTIVE_NONE &&
        sc->tz_active != TZ_ACTIVE_UNKNOWN &&
        (newactive == TZ_ACTIVE_NONE || newactive > sc->tz_active)) {
        getnanotime(&curtime);
        timespecsub(&curtime, &sc->tz_cooling_started, &curtime);
        if (curtime.tv_sec < acpi_tz_min_runtime)
            newactive = sc->tz_active;
    }

    /* Handle user override of active mode */
    if (sc->tz_requested != TZ_ACTIVE_NONE && (newactive == TZ_ACTIVE_NONE
        || sc->tz_requested < newactive))
        newactive = sc->tz_requested;

    /* update temperature-related flags */
    newflags = TZ_THFLAG_NONE;
    if (sc->tz_zone.psv != -1 && temp >= sc->tz_zone.psv)
        newflags |= TZ_THFLAG_PSV;
    if (sc->tz_zone.cr3 != -1 && temp >= sc->tz_zone.cr3)
        newflags |= TZ_THFLAG_CR3;
    if (sc->tz_zone.hot != -1 && temp >= sc->tz_zone.hot)
        newflags |= TZ_THFLAG_HOT;
    if (sc->tz_zone.crt != -1 && temp >= sc->tz_zone.crt)
        newflags |= TZ_THFLAG_CRT;

    /* If the active cooling state has changed, we have to switch things. */
    if (sc->tz_active == TZ_ACTIVE_UNKNOWN) {
        /*
         * We don't know which cooling device is on or off,
         * so stop them all, because we now know which
         * should be on (if any).
         */
        for (i = 0; i < TZ_NUMLEVELS; i++) {
            if (sc->tz_zone.al[i].Pointer != NULL) {
                acpi_ForeachPackageObject(
                    (ACPI_OBJECT *)sc->tz_zone.al[i].Pointer,
                    acpi_tz_switch_cooler_off, sc);
            }
        }
        /* now we know that all devices are off */
        sc->tz_active = TZ_ACTIVE_NONE;
    }

    if (newactive != sc->tz_active) {
        /* Turn off unneeded cooling devices that are on, if any are */
        for (i = TZ_ACTIVE_LEVEL(sc->tz_active);
             i < TZ_ACTIVE_LEVEL(newactive); i++) {
            acpi_ForeachPackageObject(
                (ACPI_OBJECT *)sc->tz_zone.al[i].Pointer,
                acpi_tz_switch_cooler_off, sc);
        }
        /* Turn on cooling devices that are required, if any are */
        for (i = TZ_ACTIVE_LEVEL(sc->tz_active) - 1;
             i >= TZ_ACTIVE_LEVEL(newactive); i--) {
            acpi_ForeachPackageObject(
                (ACPI_OBJECT *)sc->tz_zone.al[i].Pointer,
                acpi_tz_switch_cooler_on, sc);
        }

        ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
                    "switched from %s to %s: %d.%dC\n",
                    acpi_tz_aclevel_string(sc->tz_active),
                    acpi_tz_aclevel_string(newactive), TZ_KELVTOC(temp));
        sc->tz_active = newactive;
        getnanotime(&sc->tz_cooling_started);
    }

    /* XXX (de)activate any passive cooling that may be required. */

    /*
     * If the temperature is at _HOT or _CRT, increment our event count.
     * If it has occurred enough times, shutdown the system.  This is
     * needed because some systems will report an invalid high temperature
     * for one poll cycle.  It is suspected this is due to the embedded
     * controller timing out.  A typical value is 138C for one cycle on
     * a system that is otherwise 65C.
     *
     * If we're almost at that threshold, notify the user through devd(8).
     */
    if ((newflags & (TZ_THFLAG_CR3 | TZ_THFLAG_HOT | TZ_THFLAG_CRT)) != 0) {
        sc->tz_validchecks++;
        if (sc->tz_validchecks == TZ_VALIDCHECKS) {
            device_printf(sc->tz_dev,
                "WARNING - current temperature (%d.%dC) exceeds safe limits\n",
                TZ_KELVTOC(sc->tz_temperature));
            if ((newflags & (TZ_THFLAG_HOT | TZ_THFLAG_CRT)) != 0)
                shutdown_nice(RB_POWEROFF);
            else {
                acpi_sc = acpi_device_get_parent_softc(sc->tz_dev);
                acpi_ReqSleepState(acpi_sc, ACPI_STATE_S3);
            }
        } else if (sc->tz_validchecks == TZ_NOTIFYCOUNT)
            acpi_UserNotify("Thermal", sc->tz_handle, TZ_NOTIFY_CRITICAL);
    } else {
        sc->tz_validchecks = 0;
    }
    sc->tz_thflags = newflags;

    return_VOID;
}

/*
 * Given an object, verify that it's a reference to a device of some sort,
 * and try to switch it off.
 */
static void
acpi_tz_switch_cooler_off(ACPI_OBJECT *obj, void *arg)
{
    ACPI_HANDLE                 cooler;

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    cooler = acpi_GetReference(NULL, obj);
    if (cooler == NULL) {
        ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "can't get handle\n"));
        return_VOID;
    }

    ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "called to turn %s off\n",
                     acpi_name(cooler)));
    acpi_pwr_switch_consumer(cooler, ACPI_STATE_D3);

    return_VOID;
}

/*
 * Given an object, verify that it's a reference to a device of some sort,
 * and try to switch it on.
 *
 * XXX replication of off/on function code is bad.
 */
static void
acpi_tz_switch_cooler_on(ACPI_OBJECT *obj, void *arg)
{
    struct acpi_tz_softc        *sc = (struct acpi_tz_softc *)arg;
    ACPI_HANDLE                 cooler;
    ACPI_STATUS                 status;

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    cooler = acpi_GetReference(NULL, obj);
    if (cooler == NULL) {
        ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "can't get handle\n"));
        return_VOID;
    }

    ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "called to turn %s on\n",
                     acpi_name(cooler)));
    status = acpi_pwr_switch_consumer(cooler, ACPI_STATE_D0);
    if (ACPI_FAILURE(status)) {
        ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
                    "failed to activate %s - %s\n", acpi_name(cooler),
                    AcpiFormatException(status));
    }

    return_VOID;
}

/*
 * Read/debug-print a parameter, default it to -1.
 */
static void
acpi_tz_getparam(struct acpi_tz_softc *sc, char *node, int *data)
{

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    if (ACPI_FAILURE(acpi_GetInteger(sc->tz_handle, node, data))) {
        *data = -1;
    } else {
        ACPI_DEBUG_PRINT((ACPI_DB_VALUES, "%s.%s = %d\n",
                         acpi_name(sc->tz_handle), node, *data));
    }

    return_VOID;
}

/*
 * Sanity-check a temperature value.  Assume that setpoints
 * should be between 0C and 200C.
 */
static void
acpi_tz_sanity(struct acpi_tz_softc *sc, int *val, char *what)
{
    if (*val != -1 && (*val < TZ_ZEROC || *val > TZ_ZEROC + 2000)) {
        /*
         * If the value we are checking is _TMP, warn the user only
         * once. This avoids spamming messages if, for instance, the
         * sensor is broken and always returns an invalid temperature.
         *
         * This is only done for _TMP; other values always emit a
         * warning.
         */
        if (what != acpi_tz_tmp_name || !sc->tz_insane_tmp_notified) {
            device_printf(sc->tz_dev, "%s value is absurd, ignored (%d.%dC)\n",
                          what, TZ_KELVTOC(*val));

            /* Don't warn the user again if the read value doesn't improve. */
            if (what == acpi_tz_tmp_name)
                sc->tz_insane_tmp_notified = 1;
        }
        *val = -1;
        return;
    }

    /* This value is correct. Warn if it's incorrect again. */
    if (what == acpi_tz_tmp_name)
        sc->tz_insane_tmp_notified = 0;
}

/*
 * Respond to a sysctl on the active state node.
 */
static int
acpi_tz_active_sysctl(SYSCTL_HANDLER_ARGS)
{
    struct acpi_tz_softc        *sc;
    int                         active;
    int                         error;

    sc = (struct acpi_tz_softc *)oidp->oid_arg1;
    active = sc->tz_active;
    error = sysctl_handle_int(oidp, &active, 0, req);

    /* Error or no new value */
    if (error != 0 || req->newptr == NULL)
        return (error);
    if (active < -1 || active >= TZ_NUMLEVELS)
        return (EINVAL);

    /* Set new preferred level and re-switch */
    sc->tz_requested = active;
    acpi_tz_signal(sc, 0);
    return (0);
}

static int
acpi_tz_cooling_sysctl(SYSCTL_HANDLER_ARGS)
{
    struct acpi_tz_softc *sc;
    int enabled, error;

    sc = (struct acpi_tz_softc *)oidp->oid_arg1;
    enabled = sc->tz_cooling_enabled;
    error = sysctl_handle_int(oidp, &enabled, 0, req);

    /* Error or no new value */
    if (error != 0 || req->newptr == NULL)
        return (error);
    if (enabled != TRUE && enabled != FALSE)
        return (EINVAL);

    if (enabled) {
        if (acpi_tz_cooling_is_available(sc))
            error = acpi_tz_cooling_thread_start(sc);
        else
            error = ENODEV;
        if (error)
            enabled = FALSE;
    }
    sc->tz_cooling_enabled = enabled;
    return (error);
}

static int
acpi_tz_temp_sysctl(SYSCTL_HANDLER_ARGS)
{
    struct acpi_tz_softc        *sc;
    int                         temp, *temp_ptr;
    int                         error;

    sc = oidp->oid_arg1;
    temp_ptr = (int *)(void *)(uintptr_t)((uintptr_t)sc + oidp->oid_arg2);
    temp = *temp_ptr;
    error = sysctl_handle_int(oidp, &temp, 0, req);

    /* Error or no new value */
    if (error != 0 || req->newptr == NULL)
        return (error);

    /* Only allow changing settings if override is set. */
    if (!acpi_tz_override)
        return (EPERM);

    /* Check user-supplied value for sanity. */
    acpi_tz_sanity(sc, &temp, "user-supplied temp");
    if (temp == -1)
        return (EINVAL);

    *temp_ptr = temp;
    return (0);
}

static int
acpi_tz_passive_sysctl(SYSCTL_HANDLER_ARGS)
{
    struct acpi_tz_softc        *sc;
    int                         val, *val_ptr;
    int                         error;

    sc = oidp->oid_arg1;
    val_ptr = (int *)(void *)(uintptr_t)((uintptr_t)sc + oidp->oid_arg2);
    val = *val_ptr;
    error = sysctl_handle_int(oidp, &val, 0, req);

    /* Error or no new value */
    if (error != 0 || req->newptr == NULL)
        return (error);

    /* Only allow changing settings if override is set. */
    if (!acpi_tz_override)
        return (EPERM);

    *val_ptr = val;
    return (0);
}

static void
acpi_tz_notify_handler(ACPI_HANDLE h, UINT32 notify, void *context)
{
    struct acpi_tz_softc        *sc = (struct acpi_tz_softc *)context;

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    switch (notify) {
    case TZ_NOTIFY_TEMPERATURE:
        /* Temperature change occurred */
        acpi_tz_signal(sc, 0);
        break;
    case TZ_NOTIFY_DEVICES:
    case TZ_NOTIFY_LEVELS:
        /* Zone devices/setpoints changed */
        acpi_tz_signal(sc, TZ_FLAG_GETSETTINGS);
        break;
    default:
        ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
                    "unknown Notify event 0x%x\n", notify);
        break;
    }

    acpi_UserNotify("Thermal", h, notify);

    return_VOID;
}

static void
acpi_tz_signal(struct acpi_tz_softc *sc, int flags)
{
    ACPI_LOCK(thermal);
    sc->tz_flags |= flags;
    ACPI_UNLOCK(thermal);
    wakeup(&acpi_tz_proc);
}

/*
 * Notifies can be generated asynchronously but have also been seen to be
 * triggered by other thermal methods.  One system generates a notify of
 * 0x81 when the fan is turned on or off.  Another generates it when _SCP
 * is called.  To handle these situations, we check the zone via
 * acpi_tz_monitor() before evaluating changes to setpoints or the cooling
 * policy.
 */
static void
acpi_tz_timeout(struct acpi_tz_softc *sc, int flags)
{

    /* Check the current temperature and take action based on it */
    acpi_tz_monitor(sc);

    /* If requested, get the power profile settings. */
    if (flags & TZ_FLAG_GETPROFILE)
        acpi_tz_power_profile(sc);

    /*
     * If requested, check for new devices/setpoints.  After finding them,
     * check if we need to switch fans based on the new values.
     */
    if (flags & TZ_FLAG_GETSETTINGS) {
        acpi_tz_establish(sc);
        acpi_tz_monitor(sc);
    }

    /* XXX passive cooling actions? */
}

/*
 * System power profile may have changed; fetch and notify the
 * thermal zone accordingly.
 *
 * Since this can be called from an arbitrary eventhandler, it needs
 * to get the ACPI lock itself.
 */
static void
acpi_tz_power_profile(void *arg)
{
    ACPI_STATUS                 status;
    struct acpi_tz_softc        *sc = (struct acpi_tz_softc *)arg;
    int                         state;

    state = power_profile_get_state();
    if (state != POWER_PROFILE_PERFORMANCE && state != POWER_PROFILE_ECONOMY)
        return;

    /* check that we haven't decided there's no _SCP method */
    if ((sc->tz_flags & TZ_FLAG_NO_SCP) == 0) {
        /* Call _SCP to set the new profile */
        status = acpi_SetInteger(sc->tz_handle, "_SCP",
            (state == POWER_PROFILE_PERFORMANCE) ? 0 : 1);
        if (ACPI_FAILURE(status)) {
            if (status != AE_NOT_FOUND)
                ACPI_VPRINT(sc->tz_dev,
                            acpi_device_get_parent_softc(sc->tz_dev),
                            "can't evaluate %s._SCP - %s\n",
                            acpi_name(sc->tz_handle),
                            AcpiFormatException(status));
            sc->tz_flags |= TZ_FLAG_NO_SCP;
        } else {
            /* We have to re-evaluate the entire zone now */
            acpi_tz_signal(sc, TZ_FLAG_GETSETTINGS);
        }
    }
}

/*
 * Thermal zone monitor thread.
 */
static void
acpi_tz_thread(void *arg)
{
    devclass_t  acpi_tz_devclass;
    device_t    *devs;
    int         devcount, i;
    int         flags;
    struct acpi_tz_softc **sc;

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    acpi_tz_devclass = devclass_find("acpi_tz");
    devs = NULL;
    devcount = 0;
    sc = NULL;

    for (;;) {
        /* If the number of devices has changed, re-evaluate. */
        if (devclass_get_count(acpi_tz_devclass) != devcount) {
            if (devs != NULL) {
                free(devs, M_TEMP);
                free(sc, M_TEMP);
            }
            devclass_get_devices(acpi_tz_devclass, &devs, &devcount);
            sc = malloc(sizeof(struct acpi_tz_softc *) * devcount, M_TEMP,
                        M_WAITOK | M_ZERO);
            for (i = 0; i < devcount; i++)
                sc[i] = device_get_softc(devs[i]);
        }

        /* Check for temperature events and act on them. */
        for (i = 0; i < devcount; i++) {
            ACPI_LOCK(thermal);
            flags = sc[i]->tz_flags;
            sc[i]->tz_flags &= TZ_FLAG_NO_SCP;
            ACPI_UNLOCK(thermal);
            acpi_tz_timeout(sc[i], flags);
        }

        /* If more work to do, don't go to sleep yet. */
        ACPI_LOCK(thermal);
        for (i = 0; i < devcount; i++) {
            if (sc[i]->tz_flags & ~TZ_FLAG_NO_SCP)
                break;
        }

        /*
         * If we have no more work, sleep for a while, setting PDROP so that
         * the mutex will not be reacquired.  Otherwise, drop the mutex and
         * loop to handle more events.
         */
        if (i == devcount)
            msleep(&acpi_tz_proc, &thermal_mutex, PZERO | PDROP, "tzpoll",
                hz * acpi_tz_polling_rate);
        else
            ACPI_UNLOCK(thermal);
    }
}

static int
acpi_tz_cpufreq_restore(struct acpi_tz_softc *sc)
{
    device_t dev;
    int error;

    if (!sc->tz_cooling_updated)
        return (0);
    if ((dev = devclass_get_device(devclass_find("cpufreq"), 0)) == NULL)
        return (ENXIO);
    ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
        "temperature %d.%dC: resuming previous clock speed (%d MHz)\n",
        TZ_KELVTOC(sc->tz_temperature), sc->tz_cooling_saved_freq);
    error = CPUFREQ_SET(dev, NULL, CPUFREQ_PRIO_KERN);
    if (error == 0)
        sc->tz_cooling_updated = FALSE;
    return (error);
}

static int
acpi_tz_cpufreq_update(struct acpi_tz_softc *sc, int req)
{
    device_t dev;
    struct cf_level *levels;
    int num_levels, error, freq, desired_freq, perf, i;

    levels = malloc(CPUFREQ_MAX_LEVELS * sizeof(*levels), M_TEMP, M_NOWAIT);
    if (levels == NULL)
        return (ENOMEM);

    /*
     * Find the main device, cpufreq0.  We don't yet support independent
     * CPU frequency control on SMP.
     */
    if ((dev = devclass_get_device(devclass_find("cpufreq"), 0)) == NULL) {
        error = ENXIO;
        goto out;
    }

    /* Get the current frequency. */
    error = CPUFREQ_GET(dev, &levels[0]);
    if (error)
        goto out;
    freq = levels[0].total_set.freq;

    /* Get the current available frequency levels. */
    num_levels = CPUFREQ_MAX_LEVELS;
    error = CPUFREQ_LEVELS(dev, levels, &num_levels);
    if (error) {
        if (error == E2BIG)
            printf("cpufreq: need to increase CPUFREQ_MAX_LEVELS\n");
        goto out;
    }

    /* Calculate the desired frequency as a percent of the max frequency. */
    perf = 100 * freq / levels[0].total_set.freq - req;
    if (perf < 0)
        perf = 0;
    else if (perf > 100)
        perf = 100;
    desired_freq = levels[0].total_set.freq * perf / 100;

    if (desired_freq < freq) {
        /* Find the closest available frequency, rounding down. */
        for (i = 0; i < num_levels; i++)
            if (levels[i].total_set.freq <= desired_freq)
                break;

        /* If we didn't find a relevant setting, use the lowest. */
        if (i == num_levels)
            i--;
    } else {
        /* If we didn't decrease frequency yet, don't increase it. */
        if (!sc->tz_cooling_updated) {
            sc->tz_cooling_active = FALSE;
            goto out;
        }

        /* Use saved cpu frequency as maximum value. */
        if (desired_freq > sc->tz_cooling_saved_freq)
            desired_freq = sc->tz_cooling_saved_freq;

        /* Find the closest available frequency, rounding up. */
        for (i = num_levels - 1; i >= 0; i--)
            if (levels[i].total_set.freq >= desired_freq)
                break;

        /* If we didn't find a relevant setting, use the highest. */
        if (i == -1)
            i++;

        /* If we're going to the highest frequency, restore the old setting. */
        if (i == 0 || desired_freq == sc->tz_cooling_saved_freq) {
            error = acpi_tz_cpufreq_restore(sc);
            if (error == 0)
                sc->tz_cooling_active = FALSE;
            goto out;
        }
    }

    /* If we are going to a new frequency, activate it. */
    if (levels[i].total_set.freq != freq) {
        ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
            "temperature %d.%dC: %screasing clock speed "
            "from %d MHz to %d MHz\n",
            TZ_KELVTOC(sc->tz_temperature),
            (freq > levels[i].total_set.freq) ? "de" : "in",
            freq, levels[i].total_set.freq);
        error = CPUFREQ_SET(dev, &levels[i], CPUFREQ_PRIO_KERN);
        if (error == 0 && !sc->tz_cooling_updated) {
            sc->tz_cooling_saved_freq = freq;
            sc->tz_cooling_updated = TRUE;
        }
    }

out:
    if (levels)
        free(levels, M_TEMP);
    return (error);
}

/*
 * Passive cooling thread; monitors current temperature according to the
 * cooling interval and calculates whether to scale back CPU frequency.
 */
static void
acpi_tz_cooling_thread(void *arg)
{
    struct acpi_tz_softc *sc;
    int error, perf, curr_temp, prev_temp;

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    sc = (struct acpi_tz_softc *)arg;

    prev_temp = sc->tz_temperature;
    while (sc->tz_cooling_enabled) {
        if (sc->tz_cooling_active)
            (void)acpi_tz_get_temperature(sc);
        curr_temp = sc->tz_temperature;
        if (curr_temp >= sc->tz_zone.psv)
            sc->tz_cooling_active = TRUE;
        if (sc->tz_cooling_active) {
            perf = sc->tz_zone.tc1 * (curr_temp - prev_temp) +
                   sc->tz_zone.tc2 * (curr_temp - sc->tz_zone.psv);
            perf /= 10;

            if (perf != 0) {
                error = acpi_tz_cpufreq_update(sc, perf);

                /*
                 * If error and not simply a higher priority setting was
                 * active, disable cooling.
                 */
                if (error != 0 && error != EPERM) {
                    device_printf(sc->tz_dev,
                        "failed to set new freq, disabling passive cooling\n");
                    sc->tz_cooling_enabled = FALSE;
                }
            }
        }
        prev_temp = curr_temp;
        tsleep(&sc->tz_cooling_proc, PZERO, "cooling",
            hz * sc->tz_zone.tsp / 10);
    }
    if (sc->tz_cooling_active) {
        acpi_tz_cpufreq_restore(sc);
        sc->tz_cooling_active = FALSE;
    }
    sc->tz_cooling_proc = NULL;
    ACPI_LOCK(thermal);
    sc->tz_cooling_proc_running = FALSE;
    ACPI_UNLOCK(thermal);
    kproc_exit(0);
}

/*
 * TODO: We ignore _PSL (list of cooling devices) since cpufreq enumerates
 * all CPUs for us.  However, it's possible in the future _PSL will
 * reference non-CPU devices so we may want to support it then.
 */
static int
acpi_tz_cooling_is_available(struct acpi_tz_softc *sc)
{
    return (sc->tz_zone.tc1 != -1 && sc->tz_zone.tc2 != -1 &&
        sc->tz_zone.tsp != -1 && sc->tz_zone.tsp != 0 &&
        sc->tz_zone.psv != -1);
}

static int
acpi_tz_cooling_thread_start(struct acpi_tz_softc *sc)
{
    int error;

    ACPI_LOCK(thermal);
    if (sc->tz_cooling_proc_running) {
        ACPI_UNLOCK(thermal);
        return (0);
    }
    sc->tz_cooling_proc_running = TRUE;
    ACPI_UNLOCK(thermal);
    error = 0;
    if (sc->tz_cooling_proc == NULL) {
        error = kproc_create(acpi_tz_cooling_thread, sc,
            &sc->tz_cooling_proc, RFHIGHPID, 0, "acpi_cooling%d",
            device_get_unit(sc->tz_dev));
        if (error != 0) {
            device_printf(sc->tz_dev, "could not create thread - %d", error);
            ACPI_LOCK(thermal);
            sc->tz_cooling_proc_running = FALSE;
            ACPI_UNLOCK(thermal);
        }
    }
    return (error);
}