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 */ 25int adapter; /* 0=CGA/MDA/HGC, 1=EGA, 2=VGA+ */ 26u16 video_segment; 27int force_x, force_y; /* Don't query the BIOS for cols/rows */ 28 29int do_restore; /* Screen contents changed during mode flip */ 30int graphic_mode; /* Graphic mode with linear frame buffer */ 31 32/* Probe the video drivers and have them generate their mode lists. */ 33void 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 */ 54int 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) */ 72static 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 */ 118static 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) */ 147int 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