[deliverable/linux.git] / arch / i386 / boot / video-bios.c

/* -*- linux-c -*- ------------------------------------------------------- *
 *
 *   Copyright (C) 1991, 1992 Linus Torvalds
 *   Copyright 2007 rPath, Inc. - All Rights Reserved
 *
 *   This file is part of the Linux kernel, and is made available under
 *   the terms of the GNU General Public License version 2.
 *
 * ----------------------------------------------------------------------- */

/*
 * arch/i386/boot/video-bios.c
 *
 * Standard video BIOS modes
 *
 * We have two options for this; silent and scanned.
 */

#include "boot.h"
#include "video.h"

__videocard video_bios;

/* Set a conventional BIOS mode */
static int set_bios_mode(u8 mode);

static int bios_set_mode(struct mode_info *mi)
{
	return set_bios_mode(mi->mode - VIDEO_FIRST_BIOS);
}

static int set_bios_mode(u8 mode)
{
	u16 ax;
	u8 new_mode;

	ax = mode;		/* AH=0x00 Set Video Mode */
	asm volatile(INT10
		     : "+a" (ax)
		     : : "ebx", "ecx", "edx", "esi", "edi");

	ax = 0x0f00;		/* Get Current Video Mode */
	asm volatile(INT10
		     : "+a" (ax)
		     : : "ebx", "ecx", "edx", "esi", "edi");

	do_restore = 1;		/* Assume video contents were lost */
	new_mode = ax & 0x7f;	/* Not all BIOSes are clean with the top bit */

	if (new_mode == mode)
		return 0;	/* Mode change OK */

	if (new_mode != boot_params.screen_info.orig_video_mode) {
		/* Mode setting failed, but we didn't end up where we
		   started.  That's bad.  Try to revert to the original
		   video mode. */
		ax = boot_params.screen_info.orig_video_mode;
		asm volatile(INT10
			     : "+a" (ax)
			     : : "ebx", "ecx", "edx", "esi", "edi");
	}
	return -1;
}

static int bios_probe(void)
{
	u8 mode;
	u8 saved_mode = boot_params.screen_info.orig_video_mode;
	u16 crtc;
	struct mode_info *mi;
	int nmodes = 0;

	if (adapter != ADAPTER_EGA && adapter != ADAPTER_VGA)
		return 0;

	set_fs(0);
	crtc = vga_crtc();

	video_bios.modes = GET_HEAP(struct mode_info, 0);

	for (mode = 0x14; mode <= 0x7f; mode++) {
		if (heap_free() < sizeof(struct mode_info))
			break;

		if (mode_defined(VIDEO_FIRST_BIOS+mode))
			continue;

		if (set_bios_mode(mode))
			continue;

		/* Try to verify that it's a text mode. */

		/* Attribute Controller: make graphics controller disabled */
		if (in_idx(0x3c0, 0x10) & 0x01)
			continue;

		/* Graphics Controller: verify Alpha addressing enabled */
		if (in_idx(0x3ce, 0x06) & 0x01)
			continue;

		/* CRTC cursor location low should be zero(?) */
		if (in_idx(crtc, 0x0f))
			continue;

		mi = GET_HEAP(struct mode_info, 1);
		mi->mode = VIDEO_FIRST_BIOS+mode;
		mi->x = rdfs16(0x44a);
		mi->y = rdfs8(0x484)+1;
		nmodes++;
	}

	set_bios_mode(saved_mode);

	return nmodes;
}

__videocard video_bios =
{
	.card_name	= "BIOS (scanned)",
	.probe		= bios_probe,
	.set_mode	= bios_set_mode,
	.unsafe		= 1,
	.xmode_first	= VIDEO_FIRST_BIOS,
	.xmode_n	= 0x80,
};
Commit	Line	Data
5e8ddcbe PA	1	/* -- linux-c -- ------------------------------------------------------- *
	2	*
	3	* Copyright (C) 1991, 1992 Linus Torvalds
	4	* Copyright 2007 rPath, Inc. - All Rights Reserved
	5	*
	6	* This file is part of the Linux kernel, and is made available under
	7	* the terms of the GNU General Public License version 2.
	8	*
	9	* ----------------------------------------------------------------------- */
	10
	11	/*
	12	* arch/i386/boot/video-bios.c
	13	*
	14	* Standard video BIOS modes
	15	*
	16	* We have two options for this; silent and scanned.
	17	*/
	18
	19	#include "boot.h"
	20	#include "video.h"
	21
	22	__videocard video_bios;
	23
	24	/* Set a conventional BIOS mode */
	25	static int set_bios_mode(u8 mode);
	26
	27	static int bios_set_mode(struct mode_info *mi)
	28	{
	29	return set_bios_mode(mi->mode - VIDEO_FIRST_BIOS);
	30	}
	31
	32	static int set_bios_mode(u8 mode)
	33	{
	34	u16 ax;
	35	u8 new_mode;
	36
	37	ax = mode; /* AH=0x00 Set Video Mode */
	38	asm volatile(INT10
	39	: "+a" (ax)
	40	: : "ebx", "ecx", "edx", "esi", "edi");
	41
	42	ax = 0x0f00; /* Get Current Video Mode */
	43	asm volatile(INT10
	44	: "+a" (ax)
	45	: : "ebx", "ecx", "edx", "esi", "edi");
	46
8218d029	47	do_restore = 1; /* Assume video contents were lost */
5e8ddcbe PA	48	new_mode = ax & 0x7f; /* Not all BIOSes are clean with the top bit */
	49
	50	if (new_mode == mode)
	51	return 0; /* Mode change OK */
	52
	53	if (new_mode != boot_params.screen_info.orig_video_mode) {
	54	/* Mode setting failed, but we didn't end up where we
	55	started. That's bad. Try to revert to the original
	56	video mode. */
	57	ax = boot_params.screen_info.orig_video_mode;
	58	asm volatile(INT10
	59	: "+a" (ax)
	60	: : "ebx", "ecx", "edx", "esi", "edi");
	61	}
	62	return -1;
	63	}
	64
	65	static int bios_probe(void)
	66	{
	67	u8 mode;
	68	u8 saved_mode = boot_params.screen_info.orig_video_mode;
	69	u16 crtc;
	70	struct mode_info *mi;
	71	int nmodes = 0;
	72
	73	if (adapter != ADAPTER_EGA && adapter != ADAPTER_VGA)
	74	return 0;
	75
	76	set_fs(0);
	77	crtc = vga_crtc();
	78
	79	video_bios.modes = GET_HEAP(struct mode_info, 0);
	80
	81	for (mode = 0x14; mode <= 0x7f; mode++) {
	82	if (heap_free() < sizeof(struct mode_info))
	83	break;
	84
	85	if (mode_defined(VIDEO_FIRST_BIOS+mode))
	86	continue;
	87
	88	if (set_bios_mode(mode))
	89	continue;
	90
	91	/* Try to verify that it's a text mode. */
	92
	93	/* Attribute Controller: make graphics controller disabled */
	94	if (in_idx(0x3c0, 0x10) & 0x01)
	95	continue;
	96
	97	/* Graphics Controller: verify Alpha addressing enabled */
	98	if (in_idx(0x3ce, 0x06) & 0x01)
	99	continue;
	100
	101	/* CRTC cursor location low should be zero(?) */
	102	if (in_idx(crtc, 0x0f))
	103	continue;
	104
	105	mi = GET_HEAP(struct mode_info, 1);
	106	mi->mode = VIDEO_FIRST_BIOS+mode;
	107	mi->x = rdfs16(0x44a);
	108	mi->y = rdfs8(0x484)+1;
	109	nmodes++;
	110	}
	111
112	set_bios_mode(saved_mode);
113
114	return nmodes;
115	}
116
117	__videocard video_bios =
118	{
119	.card_name = "BIOS (scanned)",
120	.probe = bios_probe,
121	.set_mode = bios_set_mode,
122	.unsafe = 1,
123	.xmode_first = VIDEO_FIRST_BIOS,
124	.xmode_n = 0x80,
125	};