vga_isa.c

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/*-
 * Copyright (c) 1999 Kazutaka YOKOTA <[e-mail]>
 * Copyright (c) 1992-1998 S鴕en Schmidt
 * 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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * 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.
 *
 * $Id: vga_isa.c,v 1.1.2.2 1999/03/15 00:20:56 yokota Exp $
 */

#include "vga.h"
#include "opt_vga.h"
#include "opt_fb.h"
#include "opt_syscons.h"	/* should be removed in the future, XXX */

#if NVGA > 0

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/malloc.h>

#include <vm/vm.h>
#include <vm/pmap.h>

#include <machine/console.h>
#include <machine/md_var.h>
#include <machine/pc/bios.h>

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

#ifndef __i386__
#include <isa/isareg.h>
#include <isa/isavar.h>
#else
#include <i386/isa/isa.h>
#include <i386/isa/isa_device.h>
#endif

#define DRIVER_NAME		"vga"

/* cdev driver declaration */

#define ISAVGA_UNIT(dev)	minor(dev)
#define ISAVGA_MKMINOR(unit)	(unit)

typedef struct isavga_softc {
	video_adapter_t	*adp;
} isavga_softc_t;

#ifndef __i386__

#define ISAVGA_SOFTC(unit)		\
	((isavga_softc_t *)devclass_get_softc(isavga_devclass, unit))

devclass_t		isavga_devclass;

static int		isavga_probe(device_t dev);
static int		isavga_attach(device_t dev);

static device_method_t isavga_methods[] = {
	DEVMETHOD(device_probe,		isavga_probe),
	DEVMETHOD(device_attach,	isavga_attach),
	{ 0, 0 }
};

static driver_t isavga_driver = {
	DRIVER_NAME,
	isavga_methods,
	DRIVER_TYPE_TTY,
	sizeof(isavga_softc_t),
};

#else /* __i386__ */

#define ISAVGA_SOFTC(unit)	(isavga_softc[unit])

static isavga_softc_t	*isavga_softc[NVGA];

static int		isavga_probe(struct isa_device *dev);
static int		isavga_attach(struct isa_device *dev);

struct isa_driver vgadriver = {
	isavga_probe,
	isavga_attach,
	DRIVER_NAME,
	0,
};

#endif /* __i386__ */

static int		isavga_probe_unit(int unit, isavga_softc_t *sc,
					  int flags);
static int		isavga_attach_unit(int unit, isavga_softc_t *sc,
					   int flags);

#ifdef FB_INSTALL_CDEV

static d_open_t		isavgaopen;
static d_close_t	isavgaclose;
static d_read_t		isavgaread;
static d_ioctl_t	isavgaioctl;

static struct  cdevsw vga_cdevsw = {
	isavgaopen,	isavgaclose,	noread,		nowrite,	/* ?? */
	isavgaioctl,	nostop,		nullreset,	nodevtotty,
	seltrue,	nommap,		NULL,		DRIVER_NAME,
	NULL,		-1,		nodump,		nopsize,
};

#endif /* FB_INSTALL_CDEV */

#ifndef __i386__

static int
isavga_probe(device_t dev)
{
	isavga_softc_t *sc;

	sc = device_get_softc(dev);
	return isavga_probe_unit(device_get_unit(dev), sc, isa_get_flags(dev));
}

static int
isavga_attach(device_t dev)
{
	isavga_softc_t *sc;

	sc = device_get_softc(dev);
	return isavga_attach_unit(device_get_unit(dev), sc, isa_get_flags(dev));
}

#else /* __i386__ */

static int
isavga_probe(struct isa_device *dev)
{
	isavga_softc_t *sc;
	int error;

	if (dev->id_unit >= sizeof(isavga_softc)/sizeof(isavga_softc[0]))
		return 0;
	sc = isavga_softc[dev->id_unit]
	   = malloc(sizeof(*sc), M_DEVBUF, M_NOWAIT);
	if (sc == NULL)
		return 0;

	error = isavga_probe_unit(dev->id_unit, sc, dev->id_flags);
	if (error) {
		isavga_softc[dev->id_unit] = NULL;
		free(sc, M_DEVBUF);
		return 0;
	}

	dev->id_iobase = sc->adp->va_io_base;
	dev->id_maddr = (caddr_t)BIOS_PADDRTOVADDR(sc->adp->va_mem_base);
	dev->id_msize = sc->adp->va_mem_size;

	return sc->adp->va_io_size;
}

static int
isavga_attach(struct isa_device *dev)
{
	isavga_softc_t *sc;

	if (dev->id_unit >= sizeof(isavga_softc)/sizeof(isavga_softc[0]))
		return 0;
	sc = isavga_softc[dev->id_unit];
	if (sc == NULL)
		return 0;

	return ((isavga_attach_unit(dev->id_unit, sc, dev->id_flags)) ? 0 : 1);
}

#endif /* __i386__ */

static int
isavga_probe_unit(int unit, isavga_softc_t *sc, int flags)
{
	video_switch_t *sw;

	bzero(sc, sizeof(*sc));
	sw = vid_get_switch(DRIVER_NAME);
	if (sw == NULL)
		return 0;
	return (*sw->probe)(unit, &sc->adp, NULL, flags);
}

static int
isavga_attach_unit(int unit, isavga_softc_t *sc, int flags)
{
	video_switch_t *sw;
	int error;

	sw = vid_get_switch(DRIVER_NAME);
	if (sw == NULL)
		return ENXIO;

	error = (*sw->init)(unit, sc->adp, flags);
	if (error)
		return ENXIO;

#ifdef FB_INSTALL_CDEV
	/* attach a virtual frame buffer device */
	error = fb_attach(makedev(0, ISAVGA_MKMINOR(unit)), scp->adp,
			  &vga_cdevsw);
	if (error)
		return error;
#endif /* FB_INSTALL_CDEV */

	if (bootverbose)
		(*vidsw[sc->adp->va_index]->diag)(sc->adp, bootverbose);

	return 0;
}

/* LOW-LEVEL */

#include <machine/clock.h>
#include <machine/pc/vesa.h>

#define probe_done(adp)		((adp)->va_flags & V_ADP_PROBED)
#define init_done(adp)		((adp)->va_flags & V_ADP_INITIALIZED)
#define config_done(adp)	((adp)->va_flags & V_ADP_REGISTERED)

/* for compatibility with old kernel options */
#ifdef SC_ALT_SEQACCESS
#undef SC_ALT_SEQACCESS
#undef VGA_ALT_SEQACCESS
#define VGA_ALT_SEQACCESS	1
#endif

#ifdef SLOW_VGA
#undef SLOW_VGA
#undef VGA_SLOW_IOACCESS
#define VGA_SLOW_IOACCESS	1
#endif

/* architecture dependent option */
#ifdef __alpha__
#define VGA_NO_BIOS		1
#endif

/* this should really be in `rtc.h' */
#define RTC_EQUIPMENT           0x14

/* various sizes */
#define V_MODE_MAP_SIZE		(M_VGA_CG320 + 1)
#define V_MODE_PARAM_SIZE	64

/* video adapter state buffer */
struct adp_state {
    int			sig;
#define V_STATE_SIG	0x736f6962
    u_char		regs[V_MODE_PARAM_SIZE];
};
typedef struct adp_state adp_state_t;

/* video adapter information */
#define DCC_MONO	0
#define DCC_CGA40	1
#define DCC_CGA80	2
#define DCC_EGAMONO	3
#define DCC_EGA40	4
#define DCC_EGA80	5

/* 
 * NOTE: `va_window' should have a virtual address, but is initialized
 * with a physical address in the following table, as verify_adapter()
 * will perform address conversion at run-time.
 */
static video_adapter_t adapter_init_value[] = {
    /* DCC_MONO */
    { 0, KD_MONO, "mda", 0, 0, 0, 	    IO_MDA, IO_MDASIZE, MONO_CRTC,
      MDA_BUF_BASE, MDA_BUF_SIZE, MDA_BUF_BASE, MDA_BUF_SIZE, MDA_BUF_SIZE, 
      0, 0, 0, 7, 0, },
    /* DCC_CGA40 */
    { 0, KD_CGA,  "cga", 0, 0, V_ADP_COLOR, IO_CGA, IO_CGASIZE, COLOR_CRTC,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 
      0, 0, 0, 3, 0, },
    /* DCC_CGA80 */
    { 0, KD_CGA,  "cga", 0, 0, V_ADP_COLOR, IO_CGA, IO_CGASIZE, COLOR_CRTC,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 
      0, 0, 0, 3, 0, },
    /* DCC_EGAMONO */
    { 0, KD_EGA,  "ega", 0, 0, 0,	    IO_MDA, 48,	  MONO_CRTC,
      EGA_BUF_BASE, EGA_BUF_SIZE, MDA_BUF_BASE, MDA_BUF_SIZE, MDA_BUF_SIZE, 
      0, 0, 0, 7, 0, },
    /* DCC_EGA40 */
    { 0, KD_EGA,  "ega", 0, 0, V_ADP_COLOR, IO_MDA, 48,	  COLOR_CRTC,
      EGA_BUF_BASE, EGA_BUF_SIZE, CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 
      0, 0, 0, 3, 0, },
    /* DCC_EGA80 */
    { 0, KD_EGA,  "ega", 0, 0, V_ADP_COLOR, IO_MDA, 48,	  COLOR_CRTC,
      EGA_BUF_BASE, EGA_BUF_SIZE, CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 
      0, 0, 0, 3, 0, },
};

static video_adapter_t	biosadapter[2];
static int		biosadapters = 0;

/* video driver declarations */
static int			vga_configure(int flags);
       int			(*vga_sub_configure)(int flags);
static int			vga_nop(void);
static vi_probe_t		vga_probe;
static vi_init_t		vga_init;
static vi_get_info_t		vga_get_info;
static vi_query_mode_t		vga_query_mode;
static vi_set_mode_t		vga_set_mode;
static vi_save_font_t		vga_save_font;
static vi_load_font_t		vga_load_font;
static vi_show_font_t		vga_show_font;
static vi_save_palette_t	vga_save_palette;
static vi_load_palette_t	vga_load_palette;
static vi_set_border_t		vga_set_border;
static vi_save_state_t		vga_save_state;
static vi_load_state_t		vga_load_state;
static vi_set_win_org_t		vga_set_origin;
static vi_read_hw_cursor_t	vga_read_hw_cursor;
static vi_set_hw_cursor_t	vga_set_hw_cursor;
static vi_set_hw_cursor_shape_t	vga_set_hw_cursor_shape;
static vi_mmap_t		vga_mmap;
static vi_diag_t		vga_diag;

static video_switch_t vgavidsw = {
	vga_probe,
	vga_init,
	vga_get_info,
	vga_query_mode,	
	vga_set_mode,
	vga_save_font,
	vga_load_font,
	vga_show_font,
	vga_save_palette,
	vga_load_palette,
	vga_set_border,
	vga_save_state,
	vga_load_state,
	vga_set_origin,
	vga_read_hw_cursor,
	vga_set_hw_cursor,
	vga_set_hw_cursor_shape,
	(vi_blank_display_t *)vga_nop,
	vga_mmap,
	vga_diag,
};

VIDEO_DRIVER(mda, vgavidsw, NULL);
VIDEO_DRIVER(cga, vgavidsw, NULL);
VIDEO_DRIVER(ega, vgavidsw, NULL);
VIDEO_DRIVER(vga, vgavidsw, vga_configure);

/* VGA BIOS standard video modes */
#define EOT		(-1)
#define NA		(-2)

static video_info_t bios_vmode[] = {
    /* CGA */
    { M_B40x25,     V_INFO_COLOR, 40, 25, 8,  8, 2, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    { M_C40x25,     V_INFO_COLOR, 40, 25, 8,  8, 4, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    { M_B80x25,     V_INFO_COLOR, 80, 25, 8,  8, 2, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    { M_C80x25,     V_INFO_COLOR, 80, 25, 8,  8, 4, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    /* EGA */
    { M_ENH_B40x25, V_INFO_COLOR, 40, 25, 8, 14, 2, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    { M_ENH_C40x25, V_INFO_COLOR, 40, 25, 8, 14, 4, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    { M_ENH_B80x25, V_INFO_COLOR, 80, 25, 8, 14, 2, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    { M_ENH_C80x25, V_INFO_COLOR, 80, 25, 8, 14, 4, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    /* VGA */
    { M_VGA_C40x25, V_INFO_COLOR, 40, 25, 8, 16, 4, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    { M_VGA_M80x25, 0,            80, 25, 8, 16, 2, 1,
      MDA_BUF_BASE, MDA_BUF_SIZE, MDA_BUF_SIZE, 0, 0 },
    { M_VGA_C80x25, V_INFO_COLOR, 80, 25, 8, 16, 4, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    /* MDA */
    { M_EGAMONO80x25, 0,          80, 25, 8, 14, 2, 1,
      MDA_BUF_BASE, MDA_BUF_SIZE, MDA_BUF_SIZE, 0, 0 },
    /* EGA */
    { M_ENH_B80x43, V_INFO_COLOR, 80, 43, 8,  8, 2, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    { M_ENH_C80x43, V_INFO_COLOR, 80, 43, 8,  8, 4, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    /* VGA */
    { M_VGA_M80x30, 0,            80, 30, 8, 16, 2, 1,
      MDA_BUF_BASE, MDA_BUF_SIZE, MDA_BUF_SIZE, 0, 0 },
    { M_VGA_C80x30, V_INFO_COLOR, 80, 30, 8, 16, 4, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    { M_VGA_M80x50, 0,            80, 50, 8,  8, 2, 1,
      MDA_BUF_BASE, MDA_BUF_SIZE, MDA_BUF_SIZE, 0, 0 },
    { M_VGA_C80x50, V_INFO_COLOR, 80, 50, 8,  8, 4, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    { M_VGA_M80x60, 0,            80, 60, 8,  8, 2, 1,
      MDA_BUF_BASE, MDA_BUF_SIZE, MDA_BUF_SIZE, 0, 0 },
    { M_VGA_C80x60, V_INFO_COLOR, 80, 60, 8,  8, 4, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
#ifndef VGA_NO_MODE_CHANGE
    /* CGA */
    { M_BG320,      V_INFO_COLOR | V_INFO_GRAPHICS, 320, 200, 8,  8, 2, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    { M_CG320,      V_INFO_COLOR | V_INFO_GRAPHICS, 320, 200, 8,  8, 2, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    { M_BG640,      V_INFO_COLOR | V_INFO_GRAPHICS, 640, 200, 8,  8, 1, 1,
      CGA_BUF_BASE, CGA_BUF_SIZE, CGA_BUF_SIZE, 0, 0 },
    /* EGA */
    { M_CG320_D,    V_INFO_COLOR | V_INFO_GRAPHICS, 320, 200, 8,  8, 4, 4,
      GRAPHICS_BUF_BASE, GRAPHICS_BUF_SIZE, GRAPHICS_BUF_SIZE, 0, 0 },
    { M_CG640_E,    V_INFO_COLOR | V_INFO_GRAPHICS, 640, 200, 8,  8, 4, 4,
      GRAPHICS_BUF_BASE, GRAPHICS_BUF_SIZE, GRAPHICS_BUF_SIZE, 0, 0 },
    { M_EGAMONOAPA, V_INFO_GRAPHICS,                640, 350, 8, 14, 4, 4,
      GRAPHICS_BUF_BASE, GRAPHICS_BUF_SIZE, 64*1024, 0, 0 },
    { M_ENHMONOAPA2,V_INFO_GRAPHICS,                640, 350, 8, 14, 4, 4,
      GRAPHICS_BUF_BASE, GRAPHICS_BUF_SIZE, GRAPHICS_BUF_SIZE, 0, 0 },
    { M_CG640x350,  V_INFO_COLOR | V_INFO_GRAPHICS, 640, 350, 8, 14, 2, 2,
      GRAPHICS_BUF_BASE, GRAPHICS_BUF_SIZE, GRAPHICS_BUF_SIZE, 0, 0 },
    { M_ENH_CG640,  V_INFO_COLOR | V_INFO_GRAPHICS, 640, 350, 8, 14, 4, 4,
      GRAPHICS_BUF_BASE, GRAPHICS_BUF_SIZE, GRAPHICS_BUF_SIZE, 0, 0 },
    /* VGA */
    { M_BG640x480,  V_INFO_COLOR | V_INFO_GRAPHICS, 640, 480, 8, 16, 4, 4,
      GRAPHICS_BUF_BASE, GRAPHICS_BUF_SIZE, GRAPHICS_BUF_SIZE, 0, 0 },
    { M_CG640x480,  V_INFO_COLOR | V_INFO_GRAPHICS, 640, 480, 8, 16, 4, 4,
      GRAPHICS_BUF_BASE, GRAPHICS_BUF_SIZE, GRAPHICS_BUF_SIZE, 0, 0 },
    { M_VGA_CG320,  V_INFO_COLOR | V_INFO_GRAPHICS, 320, 200, 8,  8, 8, 1,
      GRAPHICS_BUF_BASE, GRAPHICS_BUF_SIZE, GRAPHICS_BUF_SIZE, 0, 0 },
    { M_VGA_MODEX,  V_INFO_COLOR | V_INFO_GRAPHICS, 320, 240, 8,  8, 8, 1,
      GRAPHICS_BUF_BASE, GRAPHICS_BUF_SIZE, GRAPHICS_BUF_SIZE, 0, 0 },
#endif /* VGA_NO_MODE_CHANGE */

    { EOT },
};

static int		init_done = FALSE;
static u_char		*video_mode_ptr = NULL;		/* EGA/VGA */
static u_char		*video_mode_ptr2 = NULL;	/* CGA/MDA */
static u_char		*mode_map[V_MODE_MAP_SIZE];
static adp_state_t	adpstate;
static adp_state_t	adpstate2;
static int		rows_offset = 1;

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

#if !defined(VGA_NO_BIOS) && !defined(VGA_NO_MODE_CHANGE)
static void map_mode_table(u_char *map[], u_char *table, int max);
#endif
static void clear_mode_map(video_adapter_t *adp, u_char *map[], int max,
			   int color);
#if !defined(VGA_NO_BIOS) && !defined(VGA_NO_MODE_CHANGE)
static int map_mode_num(int mode);
#endif
static int map_gen_mode_num(int type, int color, int mode);
static int map_bios_mode_num(int type, int color, int bios_mode);
static u_char *get_mode_param(int mode);
#ifndef VGA_NO_BIOS
static void fill_adapter_param(int code, video_adapter_t *adp);
#endif
static int verify_adapter(video_adapter_t *adp);
static void update_adapter_info(video_adapter_t *adp, video_info_t *info);
#if !defined(VGA_NO_BIOS) && !defined(VGA_NO_MODE_CHANGE)
#define COMP_IDENTICAL	0
#define COMP_SIMILAR	1
#define COMP_DIFFERENT	2
static int comp_adpregs(u_char *buf1, u_char *buf2);
#endif
static int probe_adapters(void);

#define PARAM_BUFSIZE	6
static void set_font_mode(video_adapter_t *adp, u_char *buf);
static void set_normal_mode(video_adapter_t *adp, u_char *buf);

static void dump_buffer(u_char *buf, size_t len);

#define	ISMAPPED(pa, width)				\
	(((pa) <= (u_long)0x1000 - (width)) 		\
	 || ((pa) >= ISA_HOLE_START && (pa) <= 0x100000 - (width)))

#define	prologue(adp, flag, err)			\
	if (!init_done || !((adp)->va_flags & (flag)))	\
	    return (err)

/* a backdoor for the console driver */
static int
vga_configure(int flags)
{
    int i;

    probe_adapters();
    for (i = 0; i < biosadapters; ++i) {
	if (!probe_done(&biosadapter[i]))
	    continue;
	biosadapter[i].va_flags |= V_ADP_INITIALIZED;
	if (!config_done(&biosadapter[i])) {
	    if (vid_register(&biosadapter[i]) < 0)
		continue;
	    biosadapter[i].va_flags |= V_ADP_REGISTERED;
	}
    }
    if (vga_sub_configure != NULL)
	(*vga_sub_configure)(flags);

    return biosadapters;
}

/* local subroutines */

#if !defined(VGA_NO_BIOS) && !defined(VGA_NO_MODE_CHANGE)
/* construct the mode parameter map */
static void
map_mode_table(u_char *map[], u_char *table, int max)
{
    int i;

    for(i = 0; i < max; ++i)
	map[i] = table + i*V_MODE_PARAM_SIZE;
    for(; i < V_MODE_MAP_SIZE; ++i)
	map[i] = NULL;
}
#endif /* !VGA_NO_BIOS && !VGA_NO_MODE_CHANGE */

static void
clear_mode_map(video_adapter_t *adp, u_char *map[], int max, int color)
{
    video_info_t info;
    int i;

    /*
     * NOTE: we don't touch `bios_vmode[]' because it is shared