1 /* -*- linux-c -*- ------------------------------------------------------- *
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright 2007 rPath, Inc. - All Rights Reserved
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.
9 * ----------------------------------------------------------------------- */
12 * arch/i386/boot/video.c
24 static struct card_info cards[]; /* List of cards to probe for */
29 int adapter; /* 0=CGA/MDA/HGC, 1=EGA, 2=VGA+ */
31 int force_x, force_y; /* Don't query the BIOS for cols/rows */
33 int do_restore = 0; /* Screen contents changed during mode flip */
34 int graphic_mode; /* Graphic mode with linear frame buffer */
36 static void store_cursor_position(void)
44 : "=d" (curpos), "+a" (ax), "+b" (bx)
45 : : "ecx", "esi", "edi");
47 boot_params.screen_info.orig_x = curpos;
48 boot_params.screen_info.orig_y = curpos >> 8;
51 static void store_video_mode(void)
55 /* N.B.: the saving of the video page here is a bit silly,
56 since we pretty much assume page 0 everywhere. */
59 : "+a" (ax), "=b" (page)
60 : : "ecx", "edx", "esi", "edi");
62 /* Not all BIOSes are clean with respect to the top bit */
63 boot_params.screen_info.orig_video_mode = ax & 0x7f;
64 boot_params.screen_info.orig_video_page = page;
68 * Store the video mode parameters for later usage by the kernel.
69 * This is done by asking the BIOS except for the rows/columns
70 * parameters in the default 80x25 mode -- these are set directly,
71 * because some very obscure BIOSes supply insane values.
73 static void store_mode_params(void)
78 /* For graphics mode, it is up to the mode-setting driver
79 (currently only video-vesa.c) to store the parameters */
83 store_cursor_position();
86 if (boot_params.screen_info.orig_video_mode == 0x07) {
87 /* MDA, HGC, or VGA in monochrome mode */
88 video_segment = 0xb000;
90 /* CGA, EGA, VGA and so forth */
91 video_segment = 0xb800;
95 font_size = rdfs16(0x485); /* Font size, BIOS area */
96 boot_params.screen_info.orig_video_points = font_size;
99 y = (adapter == ADAPTER_CGA) ? 25 : rdfs8(0x484)+1;
106 boot_params.screen_info.orig_video_cols = x;
107 boot_params.screen_info.orig_video_lines = y;
110 /* Probe the video drivers and have them generate their mode lists. */
111 static void probe_cards(int unsafe)
113 struct card_info *card;
121 for (card = video_cards; card < video_cards_end; card++) {
122 if (card->unsafe == unsafe) {
124 card->nmodes = card->probe();
131 /* Test if a mode is defined */
132 int mode_defined(u16 mode)
134 struct card_info *card;
135 struct mode_info *mi;
138 for (card = video_cards; card < video_cards_end; card++) {
140 for (i = 0; i < card->nmodes; i++, mi++) {
141 if (mi->mode == mode)
149 /* Set mode (without recalc) */
150 static int raw_set_mode(u16 mode)
153 struct card_info *card;
154 struct mode_info *mi;
156 /* Drop the recalc bit if set */
157 mode &= ~VIDEO_RECALC;
159 /* Scan for mode based on fixed ID, position, or resolution */
161 for (card = video_cards; card < video_cards_end; card++) {
163 for (i = 0; i < card->nmodes; i++, mi++) {
164 int visible = mi->x || mi->y;
166 if ((mode == nmode && visible) ||
168 mode == (mi->y << 8)+mi->x)
169 return card->set_mode(mi);
176 /* Nothing found? Is it an "exceptional" (unprobed) mode? */
177 for (card = video_cards; card < video_cards_end; card++) {
178 if (mode >= card->xmode_first &&
179 mode < card->xmode_first+card->xmode_n) {
180 struct mode_info mix;
183 return card->set_mode(&mix);
187 /* Otherwise, failure... */
192 * Recalculate the vertical video cutoff (hack!)
194 static void vga_recalc_vertical(void)
196 unsigned int font_size, rows;
201 font_size = rdfs8(0x485); /* BIOS: font size (pixels) */
202 rows = force_y ? force_y : rdfs8(0x484)+1; /* Text rows */
204 rows *= font_size; /* Visible scan lines */
205 rows--; /* ... minus one */
209 pt = in_idx(crtc, 0x11);
210 pt &= ~0x80; /* Unlock CR0-7 */
211 out_idx(pt, crtc, 0x11);
213 out_idx((u8)rows, crtc, 0x12); /* Lower height register */
215 ov = in_idx(crtc, 0x07); /* Overflow register */
217 ov |= (rows >> (8-1)) & 0x02;
218 ov |= (rows >> (9-6)) & 0x40;
219 out_idx(ov, crtc, 0x07);
222 /* Set mode (with recalc if specified) */
223 static int set_mode(u16 mode)
227 /* Very special mode numbers... */
228 if (mode == VIDEO_CURRENT_MODE)
229 return 0; /* Nothing to do... */
230 else if (mode == NORMAL_VGA)
232 else if (mode == EXTENDED_VGA)
235 rv = raw_set_mode(mode);
239 if (mode & VIDEO_RECALC)
240 vga_recalc_vertical();
245 static unsigned int get_entry(void)
260 } else if ((key >= '0' && key <= '9') ||
261 (key >= 'A' && key <= 'Z') ||
262 (key >= 'a' && key <= 'z')) {
263 if (len < sizeof entry_buf) {
264 entry_buf[len++] = key;
268 } while (key != '\r');
272 return VIDEO_CURRENT_MODE; /* Default */
275 for (i = 0; i < len; i++) {
277 key = entry_buf[i] | 0x20;
278 v += (key > '9') ? key-'a'+10 : key-'0';
284 static void display_menu(void)
286 struct card_info *card;
287 struct mode_info *mi;
291 puts("Mode: COLSxROWS:\n");
294 for (card = video_cards; card < video_cards_end; card++) {
296 for (i = 0; i < card->nmodes; i++, mi++) {
297 int visible = mi->x && mi->y;
298 u16 mode_id = mi->mode ? mi->mode :
302 continue; /* Hidden mode */
304 printf("%c %04X %3dx%-3d %s\n",
305 ch, mode_id, mi->x, mi->y, card->card_name);
309 else if (ch == 'z' || ch == ' ')
310 ch = ' '; /* Out of keys... */
317 #define H(x) ((x)-'a'+10)
318 #define SCAN ((H('s')<<12)+(H('c')<<8)+(H('a')<<4)+H('n'))
320 static unsigned int mode_menu(void)
325 puts("Press <ENTER> to see video modes available, "
326 "<SPACE> to continue, or wait 30 sec\n");
330 key = getchar_timeout();
331 if (key == ' ' || key == 0)
332 return VIDEO_CURRENT_MODE; /* Default */
335 putchar('\a'); /* Beep! */
342 puts("Enter a video mode or \"scan\" to scan for "
343 "additional modes: ");
352 #ifdef CONFIG_VIDEO_RETAIN
353 /* Save screen content to the heap */
354 struct saved_screen {
360 static void save_screen(void)
362 /* Should be called after store_mode_params() */
363 saved.x = boot_params.screen_info.orig_video_cols;
364 saved.y = boot_params.screen_info.orig_video_lines;
365 saved.curx = boot_params.screen_info.orig_x;
366 saved.cury = boot_params.screen_info.orig_y;
368 if (heap_free() < saved.x*saved.y*sizeof(u16)+512)
369 return; /* Not enough heap to save the screen */
371 saved.data = GET_HEAP(u16, saved.x*saved.y);
373 set_fs(video_segment);
374 copy_from_fs(saved.data, 0, saved.x*saved.y*sizeof(u16));
377 static void restore_screen(void)
379 /* Should be called after store_mode_params() */
380 int xs = boot_params.screen_info.orig_video_cols;
381 int ys = boot_params.screen_info.orig_video_lines;
384 u16 *src = saved.data;
388 return; /* Can't restore onto a graphic mode */
391 return; /* No saved screen contents */
393 /* Restore screen contents */
395 set_fs(video_segment);
396 for (y = 0; y < ys; y++) {
400 int copy = (xs < saved.x) ? xs : saved.x;
401 copy_to_fs(dst, src, copy*sizeof(u16));
402 dst += copy*sizeof(u16);
404 npad = (xs < saved.x) ? 0 : xs-saved.x;
409 /* Writes "npad" blank characters to
410 video_segment:dst and advances dst */
411 asm volatile("pushw %%es ; "
418 : "+D" (dst), "+c" (npad)
419 : "bdS" (video_segment),
423 /* Restore cursor position */
424 ax = 0x0200; /* Set cursor position */
425 bx = 0; /* Page number (<< 8) */
426 dx = (saved.cury << 8)+saved.curx;
428 : "+a" (ax), "+b" (bx), "+d" (dx)
429 : : "ecx", "esi", "edi");
432 #define save_screen() ((void)0)
433 #define restore_screen() ((void)0)
438 u16 mode = boot_params.hdr.vid_mode;
453 printf("Undefined video mode number: %x\n", mode);