126 lines
2.8 KiB
C
126 lines
2.8 KiB
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 was 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,
|
||
|
|
};
|