1 /* -*- linux-c -*- ------------------------------------------------------- *
2 *
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright 2007-2008 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-mode.c
13 *
14 * Set the video mode. This is separated out into a different
15 * file in order to be shared with the ACPI wakeup code.
16 */
17
18 #include "boot.h"
19 #include "video.h"
20 #include "vesa.h"
21
22 /*
23 * Common variables
24 */
25 int adapter; /* 0=CGA/MDA/HGC, 1=EGA, 2=VGA+ */
26 u16 video_segment;
27 int force_x, force_y; /* Don't query the BIOS for cols/rows */
28
29 int do_restore; /* Screen contents changed during mode flip */
30 int graphic_mode; /* Graphic mode with linear frame buffer */
31
32 /* Probe the video drivers and have them generate their mode lists. */
33 void probe_cards(int unsafe)
34 {
35 struct card_info *card;
36 static u8 probed[2];
37
38 if (probed[unsafe])
39 return;
40
41 probed[unsafe] = 1;
42
43 for (card = video_cards; card < video_cards_end; card++) {
44 if (card->unsafe == unsafe) {
45 if (card->probe)
46 card->nmodes = card->probe();
47 else
48 card->nmodes = 0;
49 }
50 }
51 }
52
53 /* Test if a mode is defined */
54 int mode_defined(u16 mode)
55 {
56 struct card_info *card;
57 struct mode_info *mi;
58 int i;
59
60 for (card = video_cards; card < video_cards_end; card++) {
61 mi = card->modes;
62 for (i = 0; i < card->nmodes; i++, mi++) {
63 if (mi->mode == mode)
64 return 1;
65 }
66 }
67
68 return 0;
69 }
70
71 /* Set mode (without recalc) */
72 static int raw_set_mode(u16 mode, u16 *real_mode)
73 {
74 int nmode, i;
75 struct card_info *card;
76 struct mode_info *mi;
77
78 /* Drop the recalc bit if set */
79 mode &= ~VIDEO_RECALC;
80
81 /* Scan for mode based on fixed ID, position, or resolution */
82 nmode = 0;
83 for (card = video_cards; card < video_cards_end; card++) {
84 mi = card->modes;
85 for (i = 0; i < card->nmodes; i++, mi++) {
86 int visible = mi->x || mi->y;
87
88 if ((mode == nmode && visible) ||
89 mode == mi->mode ||
90 mode == (mi->y << 8)+mi->x) {
91 *real_mode = mi->mode;
92 return card->set_mode(mi);
93 }
94
95 if (visible)
96 nmode++;
97 }
98 }
99
100 /* Nothing found? Is it an "exceptional" (unprobed) mode? */
101 for (card = video_cards; card < video_cards_end; card++) {
102 if (mode >= card->xmode_first &&
103 mode < card->xmode_first+card->xmode_n) {
104 struct mode_info mix;
105 *real_mode = mix.mode = mode;
106 mix.x = mix.y = 0;
107 return card->set_mode(&mix);
108 }
109 }
110
111 /* Otherwise, failure... */
112 return -1;
113 }
114
115 /*
116 * Recalculate the vertical video cutoff (hack!)
117 */
118 static void vga_recalc_vertical(void)
119 {
120 unsigned int font_size, rows;
121 u16 crtc;
122 u8 pt, ov;
123
124 set_fs(0);
125 font_size = rdfs8(0x485); /* BIOS: font size (pixels) */
126 rows = force_y ? force_y : rdfs8(0x484)+1; /* Text rows */
127
128 rows *= font_size; /* Visible scan lines */
129 rows--; /* ... minus one */
130
131 crtc = vga_crtc();
132
133 pt = in_idx(crtc, 0x11);
134 pt &= ~0x80; /* Unlock CR0-7 */
135 out_idx(pt, crtc, 0x11);
136
137 out_idx((u8)rows, crtc, 0x12); /* Lower height register */
138
139 ov = in_idx(crtc, 0x07); /* Overflow register */
140 ov &= 0xbd;
141 ov |= (rows >> (8-1)) & 0x02;
142 ov |= (rows >> (9-6)) & 0x40;
143 out_idx(ov, crtc, 0x07);
144 }
145
146 /* Set mode (with recalc if specified) */
147 int set_mode(u16 mode)
148 {
149 int rv;
150 u16 real_mode;
151
152 /* Very special mode numbers... */
153 if (mode == VIDEO_CURRENT_MODE)
154 return 0; /* Nothing to do... */
155 else if (mode == NORMAL_VGA)
156 mode = VIDEO_80x25;
157 else if (mode == EXTENDED_VGA)
158 mode = VIDEO_8POINT;
159
160 rv = raw_set_mode(mode, &real_mode);
161 if (rv)
162 return rv;
163
164 if (mode & VIDEO_RECALC)
165 vga_recalc_vertical();
166
167 /* Save the canonical mode number for the kernel, not
168 an alias, size specification or menu position */
169 #ifndef _WAKEUP
170 boot_params.hdr.vid_mode = real_mode;
171 #endif
172 return 0;
173 }
174
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