1 // SPDX-License-Identifier: GPL-2.0-only 2 /* -*- linux-c -*- ------------------------------------------------------- * 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 * Copyright 2007-2008 rPath, Inc. - All Rights Reserved 6 * 7 * ----------------------------------------------------------------------- */ 8 9 /* 10 * arch/i386/boot/video-mode.c 11 * 12 * Set the video mode. This is separated out into a different 13 * file in order to be shared with the ACPI wakeup code. 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=EGA, 2=VGA+ */ 26 int force_x, force_y; /* Don't query the BIOS for cols/rows */ 27 int do_restore; /* Screen contents changed during mode flip */ 28 int graphic_mode; /* Graphic mode with linear frame buffer */ 29 30 /* Probe the video drivers and have them generate their mode lists. */ probe_cards(int unsafe)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_cards_end; card++) { 42 if (card->unsafe == unsafe) { 43 if (card->probe) 44 card->nmodes = card->probe(); 45 else 46 card->nmodes = 0; 47 } 48 } 49 } 50 51 /* Test if a mode is defined */ mode_defined(u16 mode)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_cards_end; card++) { 59 mi = card->modes; 60 for (i = 0; i < card->nmodes; i++, mi++) { 61 if (mi->mode == mode) 62 return 1; 63 } 64 } 65 66 return 0; 67 } 68 69 /* Set mode (without recalc) */ raw_set_mode(u16 mode,u16 * real_mode)70 static int raw_set_mode(u16 mode, u16 *real_mode) 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, position, or resolution */ 80 nmode = 0; 81 for (card = video_cards; card < video_cards_end; card++) { 82 mi = card->modes; 83 for (i = 0; i < card->nmodes; i++, mi++) { 84 int visible = mi->x || mi->y; 85 86 if ((mode == nmode && visible) || 87 mode == mi->mode || 88 mode == (mi->y << 8)+mi->x) { 89 *real_mode = mi->mode; 90 return card->set_mode(mi); 91 } 92 93 if (visible) 94 nmode++; 95 } 96 } 97 98 /* Nothing found? Is it an "exceptional" (unprobed) mode? */ 99 for (card = video_cards; card < video_cards_end; card++) { 100 if (mode >= card->xmode_first && 101 mode < card->xmode_first+card->xmode_n) { 102 struct mode_info mix; 103 *real_mode = mix.mode = mode; 104 mix.x = mix.y = 0; 105 return card->set_mode(&mix); 106 } 107 } 108 109 /* Otherwise, failure... */ 110 return -1; 111 } 112 113 /* 114 * Recalculate the vertical video cutoff (hack!) 115 */ vga_recalc_vertical(void)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: font size (pixels) */ 124 rows = force_y ? force_y : rdfs8(0x484)+1; /* Text rows */ 125 126 rows *= font_size; /* Visible scan lines */ 127 rows--; /* ... minus one */ 128 129 crtc = vga_crtc(); 130 131 pt = in_idx(crtc, 0x11); 132 pt &= ~0x80; /* Unlock CR0-7 */ 133 out_idx(pt, crtc, 0x11); 134 135 out_idx((u8)rows, crtc, 0x12); /* Lower height register */ 136 137 ov = in_idx(crtc, 0x07); /* Overflow register */ 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) */ set_mode(u16 mode)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 do... */ 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 the kernel, not 166 an alias, size specification or menu position */ 167 #ifndef _WAKEUP 168 boot_params.hdr.vid_mode = real_mode; 169 #endif 170 return 0; 171 } 172
