1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
/* -*- 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.
*
* ----------------------------------------------------------------------- */
/*
* 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 */
#ifndef _WAKEUP
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");
}
#endif
return -1;
}
static int bios_probe(void)
{
u8 mode;
#ifdef _WAKEUP
u8 saved_mode = 0x03;
#else
u8 saved_mode = boot_params.screen_info.orig_video_mode;
#endif
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->depth = 0; /* text */
mi->x = rdfs16(0x44a);
mi->y = rdfs8(0x484)+1;
nmodes++;
}
set_bios_mode(saved_mode);
return nmodes;
}
__videocard video_bios =
{
.card_name = "BIOS",
.probe = bios_probe,
.set_mode = bios_set_mode,
.unsafe = 1,
.xmode_first = VIDEO_FIRST_BIOS,
.xmode_n = 0x80,
};
|
