/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1998 Kazutaka YOKOTA and Michael Smith
 * Copyright (c) 2009-2013 Jung-uk Kim <jkim@FreeBSD.org>
 * 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 as
 *    the first lines of this file unmodified.
 * 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 AUTHORS ``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 AUTHORS 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_vga.h"
#include "opt_vesa.h"

#ifndef VGA_NO_MODE_CHANGE

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/fbio.h>
#include <sys/sysctl.h>

#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>

#include <machine/pc/bios.h>
#include <dev/fb/vesa.h>

#include <dev/fb/fbreg.h>
#include <dev/fb/vgareg.h>

#include <dev/pci/pcivar.h>

#include <isa/isareg.h>

#include <compat/x86bios/x86bios.h>

#define VESA_BIOS_OFFSET        0xc0000
#define VESA_PALETTE_SIZE       (256 * 4)
#define VESA_VIA_CLE266         "VIA CLE266\r\n"

#ifndef VESA_DEBUG
#define VESA_DEBUG      0
#endif

/* VESA video adapter state buffer stub */
struct adp_state {
        int             sig;
#define V_STATE_SIG     0x61736576
        u_char          regs[1];
};
typedef struct adp_state adp_state_t;

static struct mtx vesa_lock;
MTX_SYSINIT(vesa_lock, &vesa_lock, "VESA lock", MTX_DEF);

static int vesa_state;
static void *vesa_state_buf;
static uint32_t vesa_state_buf_offs;
static size_t vesa_state_buf_size;

static u_char *vesa_palette;
static uint32_t vesa_palette_offs;

static void *vesa_vmem_buf;
static size_t vesa_vmem_max;

static void *vesa_bios;
static uint32_t vesa_bios_offs;
static uint32_t vesa_bios_int10;
static size_t vesa_bios_size;

/* VESA video adapter */
static video_adapter_t *vesa_adp;

static SYSCTL_NODE(_debug, OID_AUTO, vesa, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL,
    "VESA debugging");
static int vesa_shadow_rom;
SYSCTL_INT(_debug_vesa, OID_AUTO, shadow_rom, CTLFLAG_RDTUN, &vesa_shadow_rom,
    0, "Enable video BIOS shadow");

/* VESA functions */
#if 0
static int                      vesa_nop(void);
#endif
static int                      vesa_error(void);
static vi_probe_t               vesa_probe;
static vi_init_t                vesa_init;
static vi_get_info_t            vesa_get_info;
static vi_query_mode_t          vesa_query_mode;
static vi_set_mode_t            vesa_set_mode;
static vi_save_font_t           vesa_save_font;
static vi_load_font_t           vesa_load_font;
static vi_show_font_t           vesa_show_font;
static vi_save_palette_t        vesa_save_palette;
static vi_load_palette_t        vesa_load_palette;
static vi_set_border_t          vesa_set_border;
static vi_save_state_t          vesa_save_state;
static vi_load_state_t          vesa_load_state;
static vi_set_win_org_t         vesa_set_origin;
static vi_read_hw_cursor_t      vesa_read_hw_cursor;
static vi_set_hw_cursor_t       vesa_set_hw_cursor;
static vi_set_hw_cursor_shape_t vesa_set_hw_cursor_shape;
static vi_blank_display_t       vesa_blank_display;
static vi_mmap_t                vesa_mmap;
static vi_ioctl_t               vesa_ioctl;
static vi_clear_t               vesa_clear;
static vi_fill_rect_t           vesa_fill_rect;
static vi_bitblt_t              vesa_bitblt;
static vi_diag_t                vesa_diag;
static int                      vesa_bios_info(int level);

static video_switch_t vesavidsw = {
        vesa_probe,
        vesa_init,
        vesa_get_info,
        vesa_query_mode,
        vesa_set_mode,
        vesa_save_font,
        vesa_load_font,
        vesa_show_font,
        vesa_save_palette,
        vesa_load_palette,
        vesa_set_border,
        vesa_save_state,
        vesa_load_state,
        vesa_set_origin,
        vesa_read_hw_cursor,
        vesa_set_hw_cursor,
        vesa_set_hw_cursor_shape,
        vesa_blank_display,
        vesa_mmap,
        vesa_ioctl,
        vesa_clear,
        vesa_fill_rect,
        vesa_bitblt,
        vesa_error,
        vesa_error,
        vesa_diag,
};

static video_switch_t *prevvidsw;

/* VESA BIOS video modes */
#define VESA_MAXMODES   64
#define EOT             (-1)
#define NA              (-2)

#define MODE_TABLE_DELTA 8

static int vesa_vmode_max;
static video_info_t *vesa_vmode;

static int vesa_init_done;
static struct vesa_info *vesa_adp_info;
static u_int16_t *vesa_vmodetab;
static char *vesa_oemstr;
static char *vesa_venderstr;
static char *vesa_prodstr;
static char *vesa_revstr;

/* local macros and functions */
#define BIOS_SADDRTOLADDR(p) ((((p) & 0xffff0000) >> 12) + ((p) & 0x0000ffff))

static int int10_set_mode(int mode);
static int vesa_bios_post(void);
static int vesa_bios_get_mode(int mode, struct vesa_mode *vmode, int flags);
static int vesa_bios_set_mode(int mode);
#if 0
static int vesa_bios_get_dac(void);
#endif
static int vesa_bios_set_dac(int bits);
static int vesa_bios_save_palette(int start, int colors, u_char *palette,
                                  int bits);
static int vesa_bios_save_palette2(int start, int colors, u_char *r, u_char *g,
                                   u_char *b, int bits);
static int vesa_bios_load_palette(int start, int colors, u_char *palette,
                                  int bits);
static int vesa_bios_load_palette2(int start, int colors, u_char *r, u_char *g,
                                   u_char *b, int bits);
#define STATE_SIZE      0
#define STATE_SAVE      1
#define STATE_LOAD      2
static size_t vesa_bios_state_buf_size(int);
static int vesa_bios_save_restore(int code, void *p);
#ifdef MODE_TABLE_BROKEN
static int vesa_bios_get_line_length(void);
#endif
static int vesa_bios_set_line_length(int pixel, int *bytes, int *lines);
#if 0
static int vesa_bios_get_start(int *x, int *y);
#endif
static int vesa_bios_set_start(int x, int y);
static int vesa_map_gen_mode_num(int type, int color, int mode);
static int vesa_translate_flags(u_int16_t vflags);
static int vesa_translate_mmodel(u_int8_t vmodel);
static int vesa_get_bpscanline(struct vesa_mode *vmode);
static int vesa_bios_init(void);
static void vesa_bios_uninit(void);
static void vesa_clear_modes(video_info_t *info, int color);

#if 0
static int vesa_get_origin(video_adapter_t *adp, off_t *offset);
#endif

/* INT 10 BIOS calls */
static int
int10_set_mode(int mode)
{
        x86regs_t regs;

        x86bios_init_regs(&regs);
        regs.R_AL = mode;

        x86bios_intr(&regs, 0x10);

        return (0);
}

static int
vesa_bios_post(void)
{
        x86regs_t regs;
        devclass_t dc;
        device_t *devs;
        device_t dev;
        int count, i, is_pci;

        if (x86bios_get_orm(vesa_bios_offs) == NULL)
                return (1);

        dev = NULL;
        is_pci = 0;

        /* Find the matching PCI video controller. */
        dc = devclass_find("vgapci");
        if (dc != NULL && devclass_get_devices(dc, &devs, &count) == 0) {
                for (i = 0; i < count; i++)
                        if (device_get_flags(devs[i]) != 0 &&
                            x86bios_match_device(vesa_bios_offs, devs[i])) {
                                dev = devs[i];
                                is_pci = 1;
                                break;
                        }
                free(devs, M_TEMP);
        }

        /* Try VGA if a PCI device is not found. */
        if (dev == NULL) {
                dc = devclass_find(VGA_DRIVER_NAME);
                if (dc != NULL)
                        dev = devclass_get_device(dc, 0);
        }

        if (bootverbose)
                printf("%s: calling BIOS POST\n",
                    dev == NULL ? "VESA" : device_get_nameunit(dev));

        x86bios_init_regs(&regs);
        if (is_pci) {
                regs.R_AH = pci_get_bus(dev);
                regs.R_AL = (pci_get_slot(dev) << 3) |
                    (pci_get_function(dev) & 0x07);
        }
        regs.R_DL = 0x80;
        x86bios_call(&regs, X86BIOS_PHYSTOSEG(vesa_bios_offs + 3),
            X86BIOS_PHYSTOOFF(vesa_bios_offs + 3));

        if (x86bios_get_intr(0x10) == 0)
                return (1);

        return (0);
}

/* VESA BIOS calls */
static int
vesa_bios_get_mode(int mode, struct vesa_mode *vmode, int flags)
{
        x86regs_t regs;
        uint32_t offs;
        void *buf;

        buf = x86bios_alloc(&offs, sizeof(*vmode), flags);
        if (buf == NULL)
                return (1);

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f01;
        regs.R_CX = mode;

        regs.R_ES = X86BIOS_PHYSTOSEG(offs);
        regs.R_DI = X86BIOS_PHYSTOOFF(offs);

        x86bios_intr(&regs, 0x10);

        if (regs.R_AX != 0x004f) {
                x86bios_free(buf, sizeof(*vmode));
                return (1);
        }

        bcopy(buf, vmode, sizeof(*vmode));
        x86bios_free(buf, sizeof(*vmode));

        return (0);
}

static int
vesa_bios_set_mode(int mode)
{
        x86regs_t regs;

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f02;
        regs.R_BX = mode;

        x86bios_intr(&regs, 0x10);

        return (regs.R_AX != 0x004f);
}

#if 0
static int
vesa_bios_get_dac(void)
{
        x86regs_t regs;

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f08;
        regs.R_BL = 1;

        x86bios_intr(&regs, 0x10);

        if (regs.R_AX != 0x004f)
                return (6);

        return (regs.R_BH);
}
#endif

static int
vesa_bios_set_dac(int bits)
{
        x86regs_t regs;

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f08;
        /* regs.R_BL = 0; */
        regs.R_BH = bits;

        x86bios_intr(&regs, 0x10);

        if (regs.R_AX != 0x004f)
                return (6);

        return (regs.R_BH);
}

static int
vesa_bios_save_palette(int start, int colors, u_char *palette, int bits)
{
        x86regs_t regs;
        int i;

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f09;
        regs.R_BL = 1;
        regs.R_CX = colors;
        regs.R_DX = start;

        regs.R_ES = X86BIOS_PHYSTOSEG(vesa_palette_offs);
        regs.R_DI = X86BIOS_PHYSTOOFF(vesa_palette_offs);

        bits = 8 - bits;
        mtx_lock(&vesa_lock);
        x86bios_intr(&regs, 0x10);
        if (regs.R_AX != 0x004f) {
                mtx_unlock(&vesa_lock);
                return (1);
        }
        for (i = 0; i < colors; ++i) {
                palette[i * 3] = vesa_palette[i * 4 + 2] << bits;
                palette[i * 3 + 1] = vesa_palette[i * 4 + 1] << bits;
                palette[i * 3 + 2] = vesa_palette[i * 4] << bits;
        }
        mtx_unlock(&vesa_lock);

        return (0);
}

static int
vesa_bios_save_palette2(int start, int colors, u_char *r, u_char *g, u_char *b,
                        int bits)
{
        x86regs_t regs;
        int i;

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f09;
        regs.R_BL = 1;
        regs.R_CX = colors;
        regs.R_DX = start;

        regs.R_ES = X86BIOS_PHYSTOSEG(vesa_palette_offs);
        regs.R_DI = X86BIOS_PHYSTOOFF(vesa_palette_offs);

        bits = 8 - bits;
        mtx_lock(&vesa_lock);
        x86bios_intr(&regs, 0x10);
        if (regs.R_AX != 0x004f) {
                mtx_unlock(&vesa_lock);
                return (1);
        }
        for (i = 0; i < colors; ++i) {
                r[i] = vesa_palette[i * 4 + 2] << bits;
                g[i] = vesa_palette[i * 4 + 1] << bits;
                b[i] = vesa_palette[i * 4] << bits;
        }
        mtx_unlock(&vesa_lock);

        return (0);
}

static int
vesa_bios_load_palette(int start, int colors, u_char *palette, int bits)
{
        x86regs_t regs;
        int i;

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f09;
        /* regs.R_BL = 0; */
        regs.R_CX = colors;
        regs.R_DX = start;

        regs.R_ES = X86BIOS_PHYSTOSEG(vesa_palette_offs);
        regs.R_DI = X86BIOS_PHYSTOOFF(vesa_palette_offs);

        bits = 8 - bits;
        mtx_lock(&vesa_lock);
        for (i = 0; i < colors; ++i) {
                vesa_palette[i * 4] = palette[i * 3 + 2] >> bits;
                vesa_palette[i * 4 + 1] = palette[i * 3 + 1] >> bits;
                vesa_palette[i * 4 + 2] = palette[i * 3] >> bits;
                vesa_palette[i * 4 + 3] = 0;
        }
        x86bios_intr(&regs, 0x10);
        mtx_unlock(&vesa_lock);

        return (regs.R_AX != 0x004f);
}

static int
vesa_bios_load_palette2(int start, int colors, u_char *r, u_char *g, u_char *b,
                        int bits)
{
        x86regs_t regs;
        int i;

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f09;
        /* regs.R_BL = 0; */
        regs.R_CX = colors;
        regs.R_DX = start;

        regs.R_ES = X86BIOS_PHYSTOSEG(vesa_palette_offs);
        regs.R_DI = X86BIOS_PHYSTOOFF(vesa_palette_offs);

        bits = 8 - bits;
        mtx_lock(&vesa_lock);
        for (i = 0; i < colors; ++i) {
                vesa_palette[i * 4] = b[i] >> bits;
                vesa_palette[i * 4 + 1] = g[i] >> bits;
                vesa_palette[i * 4 + 2] = r[i] >> bits;
                vesa_palette[i * 4 + 3] = 0;
        }
        x86bios_intr(&regs, 0x10);
        mtx_unlock(&vesa_lock);

        return (regs.R_AX != 0x004f);
}

static size_t
vesa_bios_state_buf_size(int state)
{
        x86regs_t regs;

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f04;
        /* regs.R_DL = STATE_SIZE; */
        regs.R_CX = state;

        x86bios_intr(&regs, 0x10);

        if (regs.R_AX != 0x004f)
                return (0);

        return (regs.R_BX * 64);
}

static int
vesa_bios_save_restore(int code, void *p)
{
        x86regs_t regs;

        if (code != STATE_SAVE && code != STATE_LOAD)
                return (1);

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f04;
        regs.R_DL = code;
        regs.R_CX = vesa_state;

        regs.R_ES = X86BIOS_PHYSTOSEG(vesa_state_buf_offs);
        regs.R_BX = X86BIOS_PHYSTOOFF(vesa_state_buf_offs);

        mtx_lock(&vesa_lock);
        switch (code) {
        case STATE_SAVE:
                x86bios_intr(&regs, 0x10);
                if (regs.R_AX == 0x004f)
                        bcopy(vesa_state_buf, p, vesa_state_buf_size);
                break;
        case STATE_LOAD:
                bcopy(p, vesa_state_buf, vesa_state_buf_size);
                x86bios_intr(&regs, 0x10);
                break;
        }
        mtx_unlock(&vesa_lock);

        return (regs.R_AX != 0x004f);
}

#ifdef MODE_TABLE_BROKEN
static int
vesa_bios_get_line_length(void)
{
        x86regs_t regs;

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f06;
        regs.R_BL = 1;

        x86bios_intr(&regs, 0x10);

        if (regs.R_AX != 0x004f)
                return (-1);

        return (regs.R_BX);
}
#endif

static int
vesa_bios_set_line_length(int pixel, int *bytes, int *lines)
{
        x86regs_t regs;

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f06;
        /* regs.R_BL = 0; */
        regs.R_CX = pixel;

        x86bios_intr(&regs, 0x10);

#if VESA_DEBUG > 1
        printf("bx:%d, cx:%d, dx:%d\n", regs.R_BX, regs.R_CX, regs.R_DX);
#endif
        if (regs.R_AX != 0x004f)
                return (-1);

        if (bytes != NULL)
                *bytes = regs.R_BX;
        if (lines != NULL)
                *lines = regs.R_DX;

        return (0);
}

#if 0
static int
vesa_bios_get_start(int *x, int *y)
{
        x86regs_t regs;

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f07;
        regs.R_BL = 1;

        x86bios_intr(&regs, 0x10);

        if (regs.R_AX != 0x004f)
                return (-1);

        *x = regs.R_CX;
        *y = regs.R_DX;

        return (0);
}
#endif

static int
vesa_bios_set_start(int x, int y)
{
        x86regs_t regs;

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f07;
        regs.R_BL = 0x80;
        regs.R_CX = x;
        regs.R_DX = y;

        x86bios_intr(&regs, 0x10);

        return (regs.R_AX != 0x004f);
}

/* map a generic video mode to a known mode */
static int
vesa_map_gen_mode_num(int type, int color, int mode)
{
    static struct {
        int from;
        int to;
    } mode_map[] = {
        { M_TEXT_132x25, M_VESA_C132x25 },
        { M_TEXT_132x43, M_VESA_C132x43 },
        { M_TEXT_132x50, M_VESA_C132x50 },
        { M_TEXT_132x60, M_VESA_C132x60 },
    };
    int i;

    for (i = 0; i < nitems(mode_map); ++i) {
        if (mode_map[i].from == mode)
            return (mode_map[i].to);
    }
    return (mode);
}

static int
vesa_translate_flags(u_int16_t vflags)
{
        static struct {
                u_int16_t mask;
                int set;
                int reset;
        } ftable[] = {
                { V_MODECOLOR, V_INFO_COLOR, 0 },
                { V_MODEGRAPHICS, V_INFO_GRAPHICS, 0 },
                { V_MODELFB, V_INFO_LINEAR, 0 },
                { V_MODENONVGA, V_INFO_NONVGA, 0 },
        };
        int flags;
        int i;

        for (flags = 0, i = 0; i < nitems(ftable); ++i) {
                flags |= (vflags & ftable[i].mask) ? 
                         ftable[i].set : ftable[i].reset;
        }
        return (flags);
}

static int
vesa_translate_mmodel(u_int8_t vmodel)
{
        static struct {
                u_int8_t vmodel;
                int mmodel;
        } mtable[] = {
                { V_MMTEXT,     V_INFO_MM_TEXT },
                { V_MMCGA,      V_INFO_MM_CGA },
                { V_MMHGC,      V_INFO_MM_HGC },
                { V_MMEGA,      V_INFO_MM_PLANAR },
                { V_MMPACKED,   V_INFO_MM_PACKED },
                { V_MMDIRCOLOR, V_INFO_MM_DIRECT },
        };
        int i;

        for (i = 0; mtable[i].mmodel >= 0; ++i) {
                if (mtable[i].vmodel == vmodel)
                        return (mtable[i].mmodel);
        }
        return (V_INFO_MM_OTHER);
}

static int
vesa_get_bpscanline(struct vesa_mode *vmode)
{
        int bpsl;

        if ((vmode->v_modeattr & V_MODEGRAPHICS) != 0) {
                /* Find the minimum length. */
                switch (vmode->v_bpp / vmode->v_planes) {
                case 1:
                        bpsl = vmode->v_width / 8;
                        break;
                case 2:
                        bpsl = vmode->v_width / 4;
                        break;
                case 4:
                        bpsl = vmode->v_width / 2;
                        break;
                default:
                        bpsl = vmode->v_width * ((vmode->v_bpp + 7) / 8);
                        bpsl /= vmode->v_planes;
                        break;
                }

                /* Use VBE 3.0 information if it looks sane. */
                if ((vmode->v_modeattr & V_MODELFB) != 0 &&
                    vesa_adp_info->v_version >= 0x0300 &&
                    vmode->v_linbpscanline > bpsl)
                        return (vmode->v_linbpscanline);

                /* Return the minimum if the mode table looks absurd. */
                if (vmode->v_bpscanline < bpsl)
                        return (bpsl);
        }

        return (vmode->v_bpscanline);
}

#define VESA_MAXSTR             256

#define VESA_STRCPY(dst, src)   do {                            \
        char *str;                                              \
        int i;                                                  \
        dst = malloc(VESA_MAXSTR, M_DEVBUF, M_WAITOK);          \
        str = x86bios_offset(BIOS_SADDRTOLADDR(src));           \
        for (i = 0; i < VESA_MAXSTR - 1 && str[i] != '\0'; i++) \
                dst[i] = str[i];                                \
        dst[i] = '\0';                                          \
} while (0)

static int
vesa_bios_init(void)
{
        struct vesa_mode vmode;
        struct vesa_info *buf;
        video_info_t *p;
        x86regs_t regs;
        size_t bsize;
        size_t msize;
        void *vmbuf;
        uint8_t *vbios;
        uint32_t offs;
        uint16_t vers;
        int is_via_cle266;
        int modes;
        int i;

        if (vesa_init_done)
                return (0);

        vesa_bios_offs = VESA_BIOS_OFFSET;

        /*
         * If the VBE real mode interrupt vector is not found, try BIOS POST.
         */
        vesa_bios_int10 = x86bios_get_intr(0x10);
        if (vesa_bios_int10 == 0) {
                if (vesa_bios_post() != 0)
                        return (1);
                vesa_bios_int10 = x86bios_get_intr(0x10);
                if (vesa_bios_int10 == 0)
                        return (1);
        }

        /*
         * Shadow video ROM.
         */
        offs = vesa_bios_int10;
        if (vesa_shadow_rom) {
                vbios = x86bios_get_orm(vesa_bios_offs);
                if (vbios != NULL) {
                        vesa_bios_size = vbios[2] * 512;
                        if (((VESA_BIOS_OFFSET << 12) & 0xffff0000) ==
                            (vesa_bios_int10 & 0xffff0000) &&
                            vesa_bios_size > (vesa_bios_int10 & 0xffff)) {
                                vesa_bios = x86bios_alloc(&vesa_bios_offs,
                                    vesa_bios_size, M_WAITOK);
                                bcopy(vbios, vesa_bios, vesa_bios_size);
                                offs = ((vesa_bios_offs << 12) & 0xffff0000) +
                                    (vesa_bios_int10 & 0xffff);
                                x86bios_set_intr(0x10, offs);
                        }
                }
                if (vesa_bios == NULL)
                        printf("VESA: failed to shadow video ROM\n");
        }
        if (bootverbose)
                printf("VESA: INT 0x10 vector 0x%04x:0x%04x\n",
                    (offs >> 16) & 0xffff, offs & 0xffff);

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f00;

        vmbuf = x86bios_alloc(&offs, sizeof(*buf), M_WAITOK);

        regs.R_ES = X86BIOS_PHYSTOSEG(offs);
        regs.R_DI = X86BIOS_PHYSTOOFF(offs);

        bcopy("VBE2", vmbuf, 4);        /* try for VBE2 data */
        x86bios_intr(&regs, 0x10);

        if (regs.R_AX != 0x004f || bcmp("VESA", vmbuf, 4) != 0)
                goto fail;

        vesa_adp_info = buf = malloc(sizeof(*buf), M_DEVBUF, M_WAITOK);
        bcopy(vmbuf, buf, sizeof(*buf));

        if (bootverbose) {
                printf("VESA: information block\n");
                hexdump(buf, sizeof(*buf), NULL, HD_OMIT_CHARS);
        }

        vers = buf->v_version = le16toh(buf->v_version);
        buf->v_oemstr = le32toh(buf->v_oemstr);
        buf->v_flags = le32toh(buf->v_flags);
        buf->v_modetable = le32toh(buf->v_modetable);
        buf->v_memsize = le16toh(buf->v_memsize);
        buf->v_revision = le16toh(buf->v_revision);
        buf->v_venderstr = le32toh(buf->v_venderstr);
        buf->v_prodstr = le32toh(buf->v_prodstr);
        buf->v_revstr = le32toh(buf->v_revstr);

        if (vers < 0x0102) {
                printf("VESA: VBE version %d.%d is not supported; "
                    "version 1.2 or later is required.\n",
                    ((vers & 0xf000) >> 12) * 10 + ((vers & 0x0f00) >> 8),
                    ((vers & 0x00f0) >> 4) * 10 + (vers & 0x000f));
                goto fail;
        }

        VESA_STRCPY(vesa_oemstr, buf->v_oemstr);
        if (vers >= 0x0200) {
                VESA_STRCPY(vesa_venderstr, buf->v_venderstr);
                VESA_STRCPY(vesa_prodstr, buf->v_prodstr);
                VESA_STRCPY(vesa_revstr, buf->v_revstr);
        }
        is_via_cle266 = strncmp(vesa_oemstr, VESA_VIA_CLE266,
            sizeof(VESA_VIA_CLE266)) == 0;

        if (buf->v_modetable == 0)
                goto fail;

        msize = (size_t)buf->v_memsize * 64 * 1024;

        vesa_vmodetab = x86bios_offset(BIOS_SADDRTOLADDR(buf->v_modetable));

        for (i = 0, modes = 0; (i < (M_VESA_MODE_MAX - M_VESA_BASE + 1)) &&
            (vesa_vmodetab[i] != 0xffff); ++i) {
                vesa_vmodetab[i] = le16toh(vesa_vmodetab[i]);
                if (vesa_bios_get_mode(vesa_vmodetab[i], &vmode, M_WAITOK))
                        continue;

                vmode.v_modeattr = le16toh(vmode.v_modeattr);
                vmode.v_wgran = le16toh(vmode.v_wgran);
                vmode.v_wsize = le16toh(vmode.v_wsize);
                vmode.v_waseg = le16toh(vmode.v_waseg);
                vmode.v_wbseg = le16toh(vmode.v_wbseg);
                vmode.v_posfunc = le32toh(vmode.v_posfunc);
                vmode.v_bpscanline = le16toh(vmode.v_bpscanline);
                vmode.v_width = le16toh(vmode.v_width);
                vmode.v_height = le16toh(vmode.v_height);
                vmode.v_lfb = le32toh(vmode.v_lfb);
                vmode.v_offscreen = le32toh(vmode.v_offscreen);
                vmode.v_offscreensize = le16toh(vmode.v_offscreensize);
                vmode.v_linbpscanline = le16toh(vmode.v_linbpscanline);
                vmode.v_maxpixelclock = le32toh(vmode.v_maxpixelclock);

                /* reject unsupported modes */
#if 0
                if ((vmode.v_modeattr &
                    (V_MODESUPP | V_MODEOPTINFO | V_MODENONVGA)) !=
                    (V_MODESUPP | V_MODEOPTINFO))
                        continue;
#else
                if ((vmode.v_modeattr & V_MODEOPTINFO) == 0) {
#if VESA_DEBUG > 1
                        printf("Rejecting VESA %s mode: %d x %d x %d bpp "
                            " attr = %x\n",
                            vmode.v_modeattr & V_MODEGRAPHICS ?
                            "graphics" : "text",
                            vmode.v_width, vmode.v_height, vmode.v_bpp,
                            vmode.v_modeattr);
#endif
                        continue;
                }
#endif

                bsize = vesa_get_bpscanline(&vmode) * vmode.v_height;
                if ((vmode.v_modeattr & V_MODEGRAPHICS) != 0)
                        bsize *= vmode.v_planes;

                /* Does it have enough memory to support this mode? */
                if (msize < bsize) {
#if VESA_DEBUG > 1
                        printf("Rejecting VESA %s mode: %d x %d x %d bpp "
                            " attr = %x, not enough memory\n",
                            vmode.v_modeattr & V_MODEGRAPHICS ?
                            "graphics" : "text",
                            vmode.v_width, vmode.v_height, vmode.v_bpp,
                            vmode.v_modeattr);
#endif
                        continue;
                }
                if (bsize > vesa_vmem_max)
                        vesa_vmem_max = bsize;

                /* expand the array if necessary */
                if (modes >= vesa_vmode_max) {
                        vesa_vmode_max += MODE_TABLE_DELTA;
                        p = malloc(sizeof(*vesa_vmode) * (vesa_vmode_max + 1),
                            M_DEVBUF, M_WAITOK);
#if VESA_DEBUG > 1
                        printf("vesa_bios_init(): modes:%d, vesa_mode_max:%d\n",
                            modes, vesa_vmode_max);
#endif
                        if (modes > 0) {
                                bcopy(vesa_vmode, p, sizeof(*vesa_vmode)*modes);
                                free(vesa_vmode, M_DEVBUF);
                        }
                        vesa_vmode = p;
                }

#if VESA_DEBUG > 1
                printf("Found VESA %s mode: %d x %d x %d bpp\n",
                    vmode.v_modeattr & V_MODEGRAPHICS ? "graphics" : "text",
                    vmode.v_width, vmode.v_height, vmode.v_bpp);
#endif
                if (is_via_cle266) {
                    if ((vmode.v_width & 0xff00) >> 8 == vmode.v_height - 1) {
                        vmode.v_width &= 0xff;
                        vmode.v_waseg = 0xb8000 >> 4;
                    }
                }

                /* copy some fields */
                bzero(&vesa_vmode[modes], sizeof(vesa_vmode[modes]));
                vesa_vmode[modes].vi_mode = vesa_vmodetab[i];
                vesa_vmode[modes].vi_width = vmode.v_width;
                vesa_vmode[modes].vi_height = vmode.v_height;
                vesa_vmode[modes].vi_depth = vmode.v_bpp;
                vesa_vmode[modes].vi_planes = vmode.v_planes;
                vesa_vmode[modes].vi_cwidth = vmode.v_cwidth;
                vesa_vmode[modes].vi_cheight = vmode.v_cheight;
                vesa_vmode[modes].vi_window = (vm_offset_t)vmode.v_waseg << 4;
                /* XXX window B */
                vesa_vmode[modes].vi_window_size = vmode.v_wsize * 1024;
                vesa_vmode[modes].vi_window_gran = vmode.v_wgran * 1024;
                if (vmode.v_modeattr & V_MODELFB)
                        vesa_vmode[modes].vi_buffer = vmode.v_lfb;
                vesa_vmode[modes].vi_buffer_size = bsize;
                vesa_vmode[modes].vi_mem_model =
                    vesa_translate_mmodel(vmode.v_memmodel);
                switch (vesa_vmode[modes].vi_mem_model) {
                case V_INFO_MM_DIRECT:
                        if ((vmode.v_modeattr & V_MODELFB) != 0 &&
                            vers >= 0x0300) {
                                vesa_vmode[modes].vi_pixel_fields[0] =
                                    vmode.v_linredfieldpos;
                                vesa_vmode[modes].vi_pixel_fields[1] =
                                    vmode.v_lingreenfieldpos;
                                vesa_vmode[modes].vi_pixel_fields[2] =
                                    vmode.v_linbluefieldpos;
                                vesa_vmode[modes].vi_pixel_fields[3] =
                                    vmode.v_linresfieldpos;
                                vesa_vmode[modes].vi_pixel_fsizes[0] =
                                    vmode.v_linredmasksize;
                                vesa_vmode[modes].vi_pixel_fsizes[1] =
                                    vmode.v_lingreenmasksize;
                                vesa_vmode[modes].vi_pixel_fsizes[2] =
                                    vmode.v_linbluemasksize;
                                vesa_vmode[modes].vi_pixel_fsizes[3] =
                                    vmode.v_linresmasksize;
                        } else {
                                vesa_vmode[modes].vi_pixel_fields[0] =
                                    vmode.v_redfieldpos;
                                vesa_vmode[modes].vi_pixel_fields[1] =
                                    vmode.v_greenfieldpos;
                                vesa_vmode[modes].vi_pixel_fields[2] =
                                    vmode.v_bluefieldpos;
                                vesa_vmode[modes].vi_pixel_fields[3] =
                                    vmode.v_resfieldpos;
                                vesa_vmode[modes].vi_pixel_fsizes[0] =
                                    vmode.v_redmasksize;
                                vesa_vmode[modes].vi_pixel_fsizes[1] =
                                    vmode.v_greenmasksize;
                                vesa_vmode[modes].vi_pixel_fsizes[2] =
                                    vmode.v_bluemasksize;
                                vesa_vmode[modes].vi_pixel_fsizes[3] =
                                    vmode.v_resmasksize;
                        }
                        /* FALLTHROUGH */
                case V_INFO_MM_PACKED:
                        vesa_vmode[modes].vi_pixel_size = (vmode.v_bpp + 7) / 8;
                        break;
                }
                vesa_vmode[modes].vi_flags =
                    vesa_translate_flags(vmode.v_modeattr) | V_INFO_VESA;

                ++modes;
        }
        if (vesa_vmode != NULL)
                vesa_vmode[modes].vi_mode = EOT;

        if (bootverbose)
                printf("VESA: %d mode(s) found\n", modes);

        if (modes == 0)
                goto fail;

        x86bios_free(vmbuf, sizeof(*buf));

        /* Probe supported save/restore states. */
        for (i = 0; i < 4; i++)
                if (vesa_bios_state_buf_size(1 << i) > 0)
                        vesa_state |= 1 << i;
        if (vesa_state != 0)
                vesa_state_buf_size = vesa_bios_state_buf_size(vesa_state);
        vesa_palette = x86bios_alloc(&vesa_palette_offs,
            VESA_PALETTE_SIZE + vesa_state_buf_size, M_WAITOK);
        if (vesa_state_buf_size > 0) {
                vesa_state_buf = vesa_palette + VESA_PALETTE_SIZE;
                vesa_state_buf_offs = vesa_palette_offs + VESA_PALETTE_SIZE;
        }

        return (0);

fail:
        x86bios_free(vmbuf, sizeof(buf));
        vesa_bios_uninit();
        return (1);
}

static void
vesa_bios_uninit(void)
{

        if (vesa_bios != NULL) {
                x86bios_set_intr(0x10, vesa_bios_int10);
                vesa_bios_offs = VESA_BIOS_OFFSET;
                x86bios_free(vesa_bios, vesa_bios_size);
                vesa_bios = NULL;
        }
        if (vesa_adp_info != NULL) {
                free(vesa_adp_info, M_DEVBUF);
                vesa_adp_info = NULL;
        }
        if (vesa_oemstr != NULL) {
                free(vesa_oemstr, M_DEVBUF);
                vesa_oemstr = NULL;
        }
        if (vesa_venderstr != NULL) {
                free(vesa_venderstr, M_DEVBUF);
                vesa_venderstr = NULL;
        }
        if (vesa_prodstr != NULL) {
                free(vesa_prodstr, M_DEVBUF);
                vesa_prodstr = NULL;
        }
        if (vesa_revstr != NULL) {
                free(vesa_revstr, M_DEVBUF);
                vesa_revstr = NULL;
        }
        if (vesa_vmode != NULL) {
                free(vesa_vmode, M_DEVBUF);
                vesa_vmode = NULL;
        }
        if (vesa_palette != NULL) {
                x86bios_free(vesa_palette,
                    VESA_PALETTE_SIZE + vesa_state_buf_size);
                vesa_palette = NULL;
        }
}

static void
vesa_clear_modes(video_info_t *info, int color)
{
        while (info->vi_mode != EOT) {
                if ((info->vi_flags & V_INFO_COLOR) != color)
                        info->vi_mode = NA;
                ++info;
        }
}

/* entry points */

static int
vesa_configure(int flags)
{
        video_adapter_t *adp;
        int adapters;
        int error;
        int i;

        if (vesa_init_done)
                return (0);
        if (flags & VIO_PROBE_ONLY)
                return (0);

        /*
         * If the VESA module has already been loaded, abort loading 
         * the module this time.
         */
        for (i = 0; (adp = vid_get_adapter(i)) != NULL; ++i) {
                if (adp->va_flags & V_ADP_VESA)
                        return (ENXIO);
                if (adp->va_type == KD_VGA)
                        break;
        }

        /*
         * The VGA adapter is not found.  This is because either 
         * 1) the VGA driver has not been initialized, or 2) the VGA card
         * is not present.  If 1) is the case, we shall defer
         * initialization for now and try again later.
         */
        if (adp == NULL) {
                vga_sub_configure = vesa_configure;
                return (ENODEV);
        }

        /* count number of registered adapters */
        for (++i; vid_get_adapter(i) != NULL; ++i)
                ;
        adapters = i;

        /* call VESA BIOS */
        vesa_adp = adp;
        if (vesa_bios_init()) {
                vesa_adp = NULL;
                return (ENXIO);
        }
        vesa_adp->va_flags |= V_ADP_VESA;

        /* remove conflicting modes if we have more than one adapter */
        if (adapters > 1) {
                vesa_clear_modes(vesa_vmode,
                                 (vesa_adp->va_flags & V_ADP_COLOR) ? 
                                     V_INFO_COLOR : 0);
        }

        if ((error = vesa_load_ioctl()) == 0) {
                prevvidsw = vidsw[vesa_adp->va_index];
                vidsw[vesa_adp->va_index] = &vesavidsw;
                vesa_init_done = TRUE;
        } else {
                vesa_adp = NULL;
                return (error);
        }

        return (0);
}

#if 0
static int
vesa_nop(void)
{

        return (0);
}
#endif

static int
vesa_error(void)
{

        return (1);
}

static int
vesa_probe(int unit, video_adapter_t **adpp, void *arg, int flags)
{

        return ((*prevvidsw->probe)(unit, adpp, arg, flags));
}

static int
vesa_init(int unit, video_adapter_t *adp, int flags)
{

        return ((*prevvidsw->init)(unit, adp, flags));
}

static int
vesa_get_info(video_adapter_t *adp, int mode, video_info_t *info)
{
        int i;

        if ((*prevvidsw->get_info)(adp, mode, info) == 0)
                return (0);

        if (adp != vesa_adp)
                return (1);

        mode = vesa_map_gen_mode_num(vesa_adp->va_type, 
                                     vesa_adp->va_flags & V_ADP_COLOR, mode);
        for (i = 0; vesa_vmode[i].vi_mode != EOT; ++i) {
                if (vesa_vmode[i].vi_mode == NA)
                        continue;
                if (vesa_vmode[i].vi_mode == mode) {
                        *info = vesa_vmode[i];
                        return (0);
                }
        }
        return (1);
}

static int
vesa_query_mode(video_adapter_t *adp, video_info_t *info)
{
        int i;

        if ((*prevvidsw->query_mode)(adp, info) == 0)
                return (0);
        if (adp != vesa_adp)
                return (ENODEV);

        for (i = 0; vesa_vmode[i].vi_mode != EOT; ++i) {
                if ((info->vi_width != 0)
                    && (info->vi_width != vesa_vmode[i].vi_width))
                        continue;
                if ((info->vi_height != 0)
                    && (info->vi_height != vesa_vmode[i].vi_height))
                        continue;
                if ((info->vi_cwidth != 0)
                    && (info->vi_cwidth != vesa_vmode[i].vi_cwidth))
                        continue;
                if ((info->vi_cheight != 0)
                    && (info->vi_cheight != vesa_vmode[i].vi_cheight))
                        continue;
                if ((info->vi_depth != 0)
                    && (info->vi_depth != vesa_vmode[i].vi_depth))
                        continue;
                if ((info->vi_planes != 0)
                    && (info->vi_planes != vesa_vmode[i].vi_planes))
                        continue;
                /* pixel format, memory model */
                if ((info->vi_flags != 0)
                    && (info->vi_flags != vesa_vmode[i].vi_flags))
                        continue;
                *info = vesa_vmode[i];
                return (0);
        }
        return (ENODEV);
}

static int
vesa_set_mode(video_adapter_t *adp, int mode)
{
        video_info_t info;

        if (adp != vesa_adp)
                return ((*prevvidsw->set_mode)(adp, mode));

        mode = vesa_map_gen_mode_num(adp->va_type, 
                                     adp->va_flags & V_ADP_COLOR, mode);
#if VESA_DEBUG > 0
        printf("VESA: set_mode(): %d(%x) -> %d(%x)\n",
                adp->va_mode, adp->va_mode, mode, mode);
#endif
        /* 
         * If the current mode is a VESA mode and the new mode is not,
         * restore the state of the adapter first by setting one of the
         * standard VGA mode, so that non-standard, extended SVGA registers 
         * are set to the state compatible with the standard VGA modes. 
         * Otherwise (*prevvidsw->set_mode)() may not be able to set up 
         * the new mode correctly.
         */
        if (VESA_MODE(adp->va_mode)) {
                if (!VESA_MODE(mode) &&
                    (*prevvidsw->get_info)(adp, mode, &info) == 0) {
                        if ((adp->va_flags & V_ADP_DAC8) != 0) {
                                vesa_bios_set_dac(6);
                                adp->va_flags &= ~V_ADP_DAC8;
                        }
                        int10_set_mode(adp->va_initial_bios_mode);
                        if (adp->va_info.vi_flags & V_INFO_LINEAR)
                                pmap_unmapdev((void *)adp->va_buffer,
                                    vesa_vmem_max);
                        /* 
                         * Once (*prevvidsw->get_info)() succeeded, 
                         * (*prevvidsw->set_mode)() below won't fail...
                         */
                }
        }

        /* we may not need to handle this mode after all... */
        if (!VESA_MODE(mode) && (*prevvidsw->set_mode)(adp, mode) == 0)
                return (0);

        /* is the new mode supported? */
        if (vesa_get_info(adp, mode, &info))
                return (1);
        /* assert(VESA_MODE(mode)); */

#if VESA_DEBUG > 0
        printf("VESA: about to set a VESA mode...\n");
#endif
        /*
         * The mode change should reset the palette format to 6 bits, so
         * we must reset V_ADP_DAC8.  Some BIOSes do an incomplete reset
         * if we call them with an 8-bit palette, so reset directly.
         */
        if (adp->va_flags & V_ADP_DAC8) {
            vesa_bios_set_dac(6);
            adp->va_flags &= ~V_ADP_DAC8;
        }

        /* don't use the linear frame buffer for text modes. XXX */
        if (!(info.vi_flags & V_INFO_GRAPHICS))
                info.vi_flags &= ~V_INFO_LINEAR;

        if ((info.vi_flags & V_INFO_LINEAR) != 0)
                mode |= 0x4000;
        if (vesa_bios_set_mode(mode | 0x8000))
                return (1);

        if ((vesa_adp_info->v_flags & V_DAC8) != 0 &&
            (info.vi_flags & V_INFO_GRAPHICS) != 0 &&
            vesa_bios_set_dac(8) > 6)
                adp->va_flags |= V_ADP_DAC8;

        if (adp->va_info.vi_flags & V_INFO_LINEAR)
                pmap_unmapdev((void *)adp->va_buffer, vesa_vmem_max);

#if VESA_DEBUG > 0
        printf("VESA: mode set!\n");
#endif
        vesa_adp->va_mode = mode & 0x1ff;       /* Mode number is 9-bit. */
        vesa_adp->va_flags &= ~V_ADP_COLOR;
        vesa_adp->va_flags |= 
                (info.vi_flags & V_INFO_COLOR) ? V_ADP_COLOR : 0;
        vesa_adp->va_crtc_addr =
                (vesa_adp->va_flags & V_ADP_COLOR) ? COLOR_CRTC : MONO_CRTC;

        vesa_adp->va_flags &= ~V_ADP_CWIDTH9;
        vesa_adp->va_line_width = info.vi_buffer_size / info.vi_height;
        if ((info.vi_flags & V_INFO_GRAPHICS) != 0)
                vesa_adp->va_line_width /= info.vi_planes;

#ifdef MODE_TABLE_BROKEN
        /* If VBE function returns bigger bytes per scan line, use it. */
        {
                int bpsl = vesa_bios_get_line_length();
                if (bpsl > vesa_adp->va_line_width) {
                        vesa_adp->va_line_width = bpsl;
                        info.vi_buffer_size = bpsl * info.vi_height;
                        if ((info.vi_flags & V_INFO_GRAPHICS) != 0)
                                info.vi_buffer_size *= info.vi_planes;
                }
        }
#endif

        if (info.vi_flags & V_INFO_LINEAR) {
#if VESA_DEBUG > 1
                printf("VESA: setting up LFB\n");
#endif
                vesa_adp->va_buffer =
                    (vm_offset_t)pmap_mapdev_attr(info.vi_buffer,
                    vesa_vmem_max, PAT_WRITE_COMBINING);
                vesa_adp->va_window = vesa_adp->va_buffer;
                vesa_adp->va_window_size = info.vi_buffer_size / info.vi_planes;
                vesa_adp->va_window_gran = info.vi_buffer_size / info.vi_planes;
        } else {
                vesa_adp->va_buffer = 0;
                vesa_adp->va_window = (vm_offset_t)x86bios_offset(info.vi_window);
                vesa_adp->va_window_size = info.vi_window_size;
                vesa_adp->va_window_gran = info.vi_window_gran;
        }
        vesa_adp->va_buffer_size = info.vi_buffer_size;
        vesa_adp->va_window_orig = 0;
        vesa_adp->va_disp_start.x = 0;
        vesa_adp->va_disp_start.y = 0;
#if VESA_DEBUG > 0
        printf("vesa_set_mode(): vi_width:%d, line_width:%d\n",
               info.vi_width, vesa_adp->va_line_width);
#endif
        bcopy(&info, &vesa_adp->va_info, sizeof(vesa_adp->va_info));

        /* move hardware cursor out of the way */
        (*vidsw[vesa_adp->va_index]->set_hw_cursor)(vesa_adp, -1, -1);

        return (0);
}

static int
vesa_save_font(video_adapter_t *adp, int page, int fontsize, int fontwidth,
               u_char *data, int ch, int count)
{

        return ((*prevvidsw->save_font)(adp, page, fontsize, fontwidth, data,
            ch, count));
}

static int
vesa_load_font(video_adapter_t *adp, int page, int fontsize, int fontwidth,
               u_char *data, int ch, int count)
{

        return ((*prevvidsw->load_font)(adp, page, fontsize, fontwidth, data,
                ch, count));
}

static int
vesa_show_font(video_adapter_t *adp, int page)
{

        return ((*prevvidsw->show_font)(adp, page));
}

static int
vesa_save_palette(video_adapter_t *adp, u_char *palette)
{
        int bits;

        if (adp == vesa_adp && VESA_MODE(adp->va_mode)) {
                bits = (adp->va_flags & V_ADP_DAC8) != 0 ? 8 : 6;
                if (vesa_bios_save_palette(0, 256, palette, bits) == 0)
                        return (0);
        }

        return ((*prevvidsw->save_palette)(adp, palette));
}

static int
vesa_load_palette(video_adapter_t *adp, u_char *palette)
{
        int bits;

        if (adp == vesa_adp && VESA_MODE(adp->va_mode)) {
                bits = (adp->va_flags & V_ADP_DAC8) != 0 ? 8 : 6;
                if (vesa_bios_load_palette(0, 256, palette, bits) == 0)
                        return (0);
        }

        return ((*prevvidsw->load_palette)(adp, palette));
}

static int
vesa_set_border(video_adapter_t *adp, int color)
{

        return ((*prevvidsw->set_border)(adp, color));
}

static int
vesa_save_state(video_adapter_t *adp, void *p, size_t size)
{
        void *buf;
        size_t bsize;

        if (adp != vesa_adp || (size == 0 && vesa_state_buf_size == 0))
                return ((*prevvidsw->save_state)(adp, p, size));

        bsize = offsetof(adp_state_t, regs) + vesa_state_buf_size;
        if (size == 0)
                return (bsize);
        if (vesa_state_buf_size > 0 && size < bsize)
                return (EINVAL);

        if (vesa_vmem_buf != NULL) {
                free(vesa_vmem_buf, M_DEVBUF);
                vesa_vmem_buf = NULL;
        }
        if (VESA_MODE(adp->va_mode)) {
                buf = (void *)adp->va_buffer;
                if (buf != NULL) {
                        bsize = adp->va_buffer_size;
                        vesa_vmem_buf = malloc(bsize, M_DEVBUF, M_NOWAIT);
                        if (vesa_vmem_buf != NULL)
                                bcopy(buf, vesa_vmem_buf, bsize);
                }
        }
        if (vesa_state_buf_size == 0)
                return ((*prevvidsw->save_state)(adp, p, size));
        ((adp_state_t *)p)->sig = V_STATE_SIG;
        return (vesa_bios_save_restore(STATE_SAVE, ((adp_state_t *)p)->regs));
}

static int
vesa_load_state(video_adapter_t *adp, void *p)
{
        void *buf;
        size_t bsize;
        int error, mode;

        if (adp != vesa_adp)
                return ((*prevvidsw->load_state)(adp, p));

        /* Try BIOS POST to restore a sane state. */
        (void)vesa_bios_post();
        bsize = adp->va_buffer_size;
        mode = adp->va_mode;
        error = vesa_set_mode(adp, adp->va_initial_mode);
        if (mode != adp->va_initial_mode)
                error = vesa_set_mode(adp, mode);

        if (vesa_vmem_buf != NULL) {
                if (error == 0 && VESA_MODE(mode)) {
                        buf = (void *)adp->va_buffer;
                        if (buf != NULL)
                                bcopy(vesa_vmem_buf, buf, bsize);
                }
                free(vesa_vmem_buf, M_DEVBUF);
                vesa_vmem_buf = NULL;
        }
        if (((adp_state_t *)p)->sig != V_STATE_SIG)
                return ((*prevvidsw->load_state)(adp, p));
        return (vesa_bios_save_restore(STATE_LOAD, ((adp_state_t *)p)->regs));
}

#if 0
static int
vesa_get_origin(video_adapter_t *adp, off_t *offset)
{
        x86regs_t regs;

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f05;
        regs.R_BL = 0x10;

        x86bios_intr(&regs, 0x10);

        if (regs.R_AX != 0x004f)
                return (1);
        *offset = regs.DX * adp->va_window_gran;

        return (0);
}
#endif

static int
vesa_set_origin(video_adapter_t *adp, off_t offset)
{
        x86regs_t regs;

        /*
         * This function should return as quickly as possible to 
         * maintain good performance of the system. For this reason,
         * error checking is kept minimal and let the VESA BIOS to 
         * detect error.
         */
        if (adp != vesa_adp) 
                return ((*prevvidsw->set_win_org)(adp, offset));

        /* if this is a linear frame buffer, do nothing */
        if (adp->va_info.vi_flags & V_INFO_LINEAR)
                return (0);
        /* XXX */
        if (adp->va_window_gran == 0)
                return (1);

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f05;
        regs.R_DX = offset / adp->va_window_gran;
        
        x86bios_intr(&regs, 0x10);

        if (regs.R_AX != 0x004f)
                return (1);

        x86bios_init_regs(&regs);
        regs.R_AX = 0x4f05;
        regs.R_BL = 1;
        regs.R_DX = offset / adp->va_window_gran;
        x86bios_intr(&regs, 0x10);

        adp->va_window_orig = rounddown(offset, adp->va_window_gran);
        return (0);                     /* XXX */
}

static int
vesa_read_hw_cursor(video_adapter_t *adp, int *col, int *row)
{

        return ((*prevvidsw->read_hw_cursor)(adp, col, row));
}

static int
vesa_set_hw_cursor(video_adapter_t *adp, int col, int row)
{

        return ((*prevvidsw->set_hw_cursor)(adp, col, row));
}

static int
vesa_set_hw_cursor_shape(video_adapter_t *adp, int base, int height,
                         int celsize, int blink)
{

        return ((*prevvidsw->set_hw_cursor_shape)(adp, base, height, celsize,
            blink));
}

static int
vesa_blank_display(video_adapter_t *adp, int mode) 
{

        /* XXX: use VESA DPMS */
        return ((*prevvidsw->blank_display)(adp, mode));
}

static int
vesa_mmap(video_adapter_t *adp, vm_ooffset_t offset, vm_paddr_t *paddr,
          int prot, vm_memattr_t *memattr)
{

#if VESA_DEBUG > 0
        printf("vesa_mmap(): window:0x%tx, buffer:0x%tx, offset:0x%jx\n", 
               adp->va_info.vi_window, adp->va_info.vi_buffer, offset);
#endif

        if ((adp == vesa_adp) &&
            (adp->va_info.vi_flags & V_INFO_LINEAR) != 0) {
                /* va_window_size == va_buffer_size/vi_planes */
                /* XXX: is this correct? */
                if (offset > adp->va_window_size - PAGE_SIZE)
                        return (-1);
                *paddr = adp->va_info.vi_buffer + offset;
#ifdef VM_MEMATTR_WRITE_COMBINING
                *memattr = VM_MEMATTR_WRITE_COMBINING;
#endif
                return (0);
        }
        return ((*prevvidsw->mmap)(adp, offset, paddr, prot, memattr));
}

static int
vesa_clear(video_adapter_t *adp)
{

        return ((*prevvidsw->clear)(adp));
}

static int
vesa_fill_rect(video_adapter_t *adp, int val, int x, int y, int cx, int cy)
{

        return ((*prevvidsw->fill_rect)(adp, val, x, y, cx, cy));
}

static int
vesa_bitblt(video_adapter_t *adp,...)
{

        /* FIXME */
        return (1);
}

static int
get_palette(video_adapter_t *adp, int base, int count,
            u_char *red, u_char *green, u_char *blue, u_char *trans)
{
        u_char *r;
        u_char *g;
        u_char *b;
        int bits;
        int error;

        if (base < 0 || base >= 256 || count < 0 || count > 256)
                return (1);
        if ((base + count) > 256)
                return (1);
        if (!VESA_MODE(adp->va_mode))
                return (1);

        bits = (adp->va_flags & V_ADP_DAC8) != 0 ? 8 : 6;
        r = malloc(count * 3, M_DEVBUF, M_WAITOK);
        g = r + count;
        b = g + count;
        error = vesa_bios_save_palette2(base, count, r, g, b, bits);
        if (error == 0) {
                (void)copyout(r, red, count);
                (void)copyout(g, green, count);
                (void)copyout(b, blue, count);
                if (trans != NULL) {
                        bzero(r, count);
                        (void)copyout(r, trans, count);
                }
        }
        free(r, M_DEVBUF);

        return (error);
}

static int
set_palette(video_adapter_t *adp, int base, int count,
            u_char *red, u_char *green, u_char *blue, u_char *trans)
{
        u_char *r;
        u_char *g;
        u_char *b;
        int bits;
        int error;

        if (base < 0 || base >= 256 || count < 0 || count > 256)
                return (1);
        if ((base + count) > 256)
                return (1);
        if (!VESA_MODE(adp->va_mode))
                return (1);

        bits = (adp->va_flags & V_ADP_DAC8) != 0 ? 8 : 6;
        r = malloc(count * 3, M_DEVBUF, M_WAITOK | M_ZERO);
        g = r + count;
        b = g + count;
        if (copyin(red, r, count) != 0 ||
            copyin(green, g, count) != 0 ||
            copyin(blue, b, count) != 0) {
                error = 1;
                goto out;
        }

        error = vesa_bios_load_palette2(base, count, r, g, b, bits);
out:
        free(r, M_DEVBUF);

        return (error);
}

static int
vesa_ioctl(video_adapter_t *adp, u_long cmd, caddr_t arg)
{
        int bytes;

        if (adp != vesa_adp)
                return ((*prevvidsw->ioctl)(adp, cmd, arg));

        switch (cmd) {
        case FBIO_SETWINORG:    /* set frame buffer window origin */
                if (!VESA_MODE(adp->va_mode))
                        return (*prevvidsw->ioctl)(adp, cmd, arg);
                return (vesa_set_origin(adp, *(off_t *)arg) ? ENODEV : 0);

        case FBIO_SETDISPSTART: /* set display start address */
                if (!VESA_MODE(adp->va_mode))
                        return ((*prevvidsw->ioctl)(adp, cmd, arg));
                if (vesa_bios_set_start(((video_display_start_t *)arg)->x,
                                        ((video_display_start_t *)arg)->y))
                        return (ENODEV);
                adp->va_disp_start.x = ((video_display_start_t *)arg)->x;
                adp->va_disp_start.y = ((video_display_start_t *)arg)->y;
                return (0);

        case FBIO_SETLINEWIDTH: /* set line length in pixel */
                if (!VESA_MODE(adp->va_mode))
                        return ((*prevvidsw->ioctl)(adp, cmd, arg));
                if (vesa_bios_set_line_length(*(u_int *)arg, &bytes, NULL))
                        return (ENODEV);
                adp->va_line_width = bytes;
#if VESA_DEBUG > 1
                printf("new line width:%d\n", adp->va_line_width);
#endif
                return (0);

        case FBIO_GETPALETTE:   /* get color palette */
                if (get_palette(adp, ((video_color_palette_t *)arg)->index,
                                ((video_color_palette_t *)arg)->count,
                                ((video_color_palette_t *)arg)->red,
                                ((video_color_palette_t *)arg)->green,
                                ((video_color_palette_t *)arg)->blue,
                                ((video_color_palette_t *)arg)->transparent))
                        return ((*prevvidsw->ioctl)(adp, cmd, arg));
                return (0);


        case FBIO_SETPALETTE:   /* set color palette */
                if (set_palette(adp, ((video_color_palette_t *)arg)->index,
                                ((video_color_palette_t *)arg)->count,
                                ((video_color_palette_t *)arg)->red,
                                ((video_color_palette_t *)arg)->green,
                                ((video_color_palette_t *)arg)->blue,
                                ((video_color_palette_t *)arg)->transparent))
                        return ((*prevvidsw->ioctl)(adp, cmd, arg));
                return (0);

        case FBIOGETCMAP:       /* get color palette */
                if (get_palette(adp, ((struct fbcmap *)arg)->index,
                                ((struct fbcmap *)arg)->count,
                                ((struct fbcmap *)arg)->red,
                                ((struct fbcmap *)arg)->green,
                                ((struct fbcmap *)arg)->blue, NULL))
                        return ((*prevvidsw->ioctl)(adp, cmd, arg));
                return (0);

        case FBIOPUTCMAP:       /* set color palette */
                if (set_palette(adp, ((struct fbcmap *)arg)->index,
                                ((struct fbcmap *)arg)->count,
                                ((struct fbcmap *)arg)->red,
                                ((struct fbcmap *)arg)->green,
                                ((struct fbcmap *)arg)->blue, NULL))
                        return ((*prevvidsw->ioctl)(adp, cmd, arg));
                return (0);

        default:
                return ((*prevvidsw->ioctl)(adp, cmd, arg));
        }
}

static int
vesa_diag(video_adapter_t *adp, int level)
{
        int error;

        /* call the previous handler first */
        error = (*prevvidsw->diag)(adp, level);
        if (error)
                return (error);

        if (adp != vesa_adp)
                return (1);

        if (level <= 0)
                return (0);

        return (0);
}

static int
vesa_bios_info(int level)
{
#if VESA_DEBUG > 1
        struct vesa_mode vmode;
        int i;
#endif
        uint16_t vers;

        vers = vesa_adp_info->v_version;

        if (bootverbose) {
                /* general adapter information */
                printf(
        "VESA: v%d.%d, %dk memory, flags:0x%x, mode table:%p (%x)\n", 
                    (vers >> 12) * 10 + ((vers & 0x0f00) >> 8),
                    ((vers & 0x00f0) >> 4) * 10 + (vers & 0x000f),
                    vesa_adp_info->v_memsize * 64, vesa_adp_info->v_flags,
                    vesa_vmodetab, vesa_adp_info->v_modetable);

                /* OEM string */
                if (vesa_oemstr != NULL)
                        printf("VESA: %s\n", vesa_oemstr);
        }

        if (level <= 0)
                return (0);

        if (vers >= 0x0200 && bootverbose) {
                /* vender name, product name, product revision */
                printf("VESA: %s %s %s\n",
                        (vesa_venderstr != NULL) ? vesa_venderstr : "unknown",
                        (vesa_prodstr != NULL) ? vesa_prodstr : "unknown",
                        (vesa_revstr != NULL) ? vesa_revstr : "?");
        }

#if VESA_DEBUG > 1
        /* mode information */
        for (i = 0;
                (i < (M_VESA_MODE_MAX - M_VESA_BASE + 1))
                && (vesa_vmodetab[i] != 0xffff); ++i) {
                if (vesa_bios_get_mode(vesa_vmodetab[i], &vmode, M_NOWAIT))
                        continue;

                /* print something for diagnostic purpose */
                printf("VESA: mode:0x%03x, flags:0x%04x", 
                       vesa_vmodetab[i], vmode.v_modeattr);
                if (vmode.v_modeattr & V_MODEOPTINFO) {
                        if (vmode.v_modeattr & V_MODEGRAPHICS) {
                                printf(", G %dx%dx%d %d, ", 
                                       vmode.v_width, vmode.v_height,
                                       vmode.v_bpp, vmode.v_planes);
                        } else {
                                printf(", T %dx%d, ", 
                                       vmode.v_width, vmode.v_height);
                        }
                        printf("font:%dx%d, ", 
                               vmode.v_cwidth, vmode.v_cheight);
                        printf("pages:%d, mem:%d",
                               vmode.v_ipages + 1, vmode.v_memmodel);
                }
                if (vmode.v_modeattr & V_MODELFB) {
                        printf("\nVESA: LFB:0x%x, off:0x%x, off_size:0x%x", 
                               vmode.v_lfb, vmode.v_offscreen,
                               vmode.v_offscreensize*1024);
                }
                printf("\n");
                printf("VESA: window A:0x%x (%x), window B:0x%x (%x), ",
                       vmode.v_waseg, vmode.v_waattr,
                       vmode.v_wbseg, vmode.v_wbattr);
                printf("size:%dk, gran:%dk\n",
                       vmode.v_wsize, vmode.v_wgran);
        }
#endif /* VESA_DEBUG > 1 */

        return (0);
}

/* module loading */

static int
vesa_load(void)
{
        int error;

        if (vesa_init_done)
                return (0);

        /* locate a VGA adapter */
        vesa_adp = NULL;
        error = vesa_configure(0);

        if (error == 0)
                vesa_bios_info(bootverbose);

        /* Don't return ENODEV, the upper layers will whine. */
        if (error == ENODEV) {
                error = 0;
                vesa_adp = NULL;
        }

        return (error);
}

static int
vesa_unload(void)
{
        int error;

        /* The driver never initialized, so make it easy to unload. */
        if (vesa_adp == NULL)
                return (0);

        /* if the adapter is currently in a VESA mode, don't unload */
        if (VESA_MODE(vesa_adp->va_mode))
                return (EBUSY);
        /* 
         * FIXME: if there is at least one vty which is in a VESA mode,
         * we shouldn't be unloading! XXX
         */

        if ((error = vesa_unload_ioctl()) == 0) {
                if (vesa_adp != NULL) {
                        if ((vesa_adp->va_flags & V_ADP_DAC8) != 0) {
                                vesa_bios_set_dac(6);
                                vesa_adp->va_flags &= ~V_ADP_DAC8;
                        }
                        vesa_adp->va_flags &= ~V_ADP_VESA;
                        vidsw[vesa_adp->va_index] = prevvidsw;
                }
        }

        vesa_bios_uninit();

        return (error);
}

static int
vesa_mod_event(module_t mod, int type, void *data)
{

        switch (type) {
        case MOD_LOAD:
                return (vesa_load());
        case MOD_UNLOAD:
                return (vesa_unload());
        }
        return (EOPNOTSUPP);
}

static moduledata_t vesa_mod = {
        "vesa",
        vesa_mod_event,
        NULL,
};

DECLARE_MODULE(vesa, vesa_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
MODULE_DEPEND(vesa, x86bios, 1, 1, 1);

#endif  /* VGA_NO_MODE_CHANGE */