1 // SPDX-License-Identifier: GPL-2.0-only 1
2 /* -*- linux-c -*- ---------------------------
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 * Copyright 2007-2008 rPath, Inc. - All Rig
6 *
7 * -------------------------------------------
8
9 /*
10 * arch/i386/boot/video-mode.c
11 *
12 * Set the video mode. This is separated out
13 * file in order to be shared with the ACPI wa
14 */
15
16 #include "boot.h"
17 #include "video.h"
18 #include "vesa.h"
19
20 #include <uapi/asm/boot.h>
21
22 /*
23 * Common variables
24 */
25 int adapter; /* 0=CGA/MDA/HGC, 1=EG
26 int force_x, force_y; /* Don't query the BIO
27 int do_restore; /* Screen contents cha
28 int graphic_mode; /* Graphic mode with l
29
30 /* Probe the video drivers and have them gener
31 void probe_cards(int unsafe)
32 {
33 struct card_info *card;
34 static u8 probed[2];
35
36 if (probed[unsafe])
37 return;
38
39 probed[unsafe] = 1;
40
41 for (card = video_cards; card < video_
42 if (card->unsafe == unsafe) {
43 if (card->probe)
44 card->nmodes =
45 else
46 card->nmodes =
47 }
48 }
49 }
50
51 /* Test if a mode is defined */
52 int mode_defined(u16 mode)
53 {
54 struct card_info *card;
55 struct mode_info *mi;
56 int i;
57
58 for (card = video_cards; card < video_
59 mi = card->modes;
60 for (i = 0; i < card->nmodes;
61 if (mi->mode == mode)
62 return 1;
63 }
64 }
65
66 return 0;
67 }
68
69 /* Set mode (without recalc) */
70 static int raw_set_mode(u16 mode, u16 *real_mo
71 {
72 int nmode, i;
73 struct card_info *card;
74 struct mode_info *mi;
75
76 /* Drop the recalc bit if set */
77 mode &= ~VIDEO_RECALC;
78
79 /* Scan for mode based on fixed ID, po
80 nmode = 0;
81 for (card = video_cards; card < video_
82 mi = card->modes;
83 for (i = 0; i < card->nmodes;
84 int visible = mi->x ||
85
86 if ((mode == nmode &&
87 mode == mi->mode |
88 mode == (mi->y <<
89 *real_mode = m
90 return card->s
91 }
92
93 if (visible)
94 nmode++;
95 }
96 }
97
98 /* Nothing found? Is it an "exception
99 for (card = video_cards; card < video_
100 if (mode >= card->xmode_first
101 mode < card->xmode_first+c
102 struct mode_info mix;
103 *real_mode = mix.mode
104 mix.x = mix.y = 0;
105 return card->set_mode(
106 }
107 }
108
109 /* Otherwise, failure... */
110 return -1;
111 }
112
113 /*
114 * Recalculate the vertical video cutoff (hack
115 */
116 static void vga_recalc_vertical(void)
117 {
118 unsigned int font_size, rows;
119 u16 crtc;
120 u8 pt, ov;
121
122 set_fs(0);
123 font_size = rdfs8(0x485); /* BIOS: fon
124 rows = force_y ? force_y : rdfs8(0x484
125
126 rows *= font_size; /* Visible sca
127 rows--; /* ... minus o
128
129 crtc = vga_crtc();
130
131 pt = in_idx(crtc, 0x11);
132 pt &= ~0x80; /* Unlock CR0-
133 out_idx(pt, crtc, 0x11);
134
135 out_idx((u8)rows, crtc, 0x12); /* Lowe
136
137 ov = in_idx(crtc, 0x07); /* Overflow r
138 ov &= 0xbd;
139 ov |= (rows >> (8-1)) & 0x02;
140 ov |= (rows >> (9-6)) & 0x40;
141 out_idx(ov, crtc, 0x07);
142 }
143
144 /* Set mode (with recalc if specified) */
145 int set_mode(u16 mode)
146 {
147 int rv;
148 u16 real_mode;
149
150 /* Very special mode numbers... */
151 if (mode == VIDEO_CURRENT_MODE)
152 return 0; /* Nothing to
153 else if (mode == NORMAL_VGA)
154 mode = VIDEO_80x25;
155 else if (mode == EXTENDED_VGA)
156 mode = VIDEO_8POINT;
157
158 rv = raw_set_mode(mode, &real_mode);
159 if (rv)
160 return rv;
161
162 if (mode & VIDEO_RECALC)
163 vga_recalc_vertical();
164
165 /* Save the canonical mode number for
166 an alias, size specification or men
167 #ifndef _WAKEUP
168 boot_params.hdr.vid_mode = real_mode;
169 #endif
170 return 0;
171 }
172
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