arch/x86/boot/video.c

   1 /* -*- linux-c -*- ------------------------------------------------------- *
   2  *
   3  *   Copyright (C) 1991, 1992 Linus Torvalds
   4  *   Copyright 2007 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.c
  13  *
  14  * Select video mode
  15  */
  16
  17 #include "boot.h"
  18 #include "video.h"
  19 #include "vesa.h"
  20
  21 static void store_cursor_position(void)
  22 {
  23         u16 curpos;
  24         u16 ax, bx;
  25
  26         ax = 0x0300;
  27         bx = 0;
  28         asm(INT10
  29             : "=d" (curpos), "+a" (ax), "+b" (bx)
  30             : : "ecx", "esi", "edi");
  31
  32         boot_params.screen_info.orig_x = curpos;
  33         boot_params.screen_info.orig_y = curpos >> 8;
  34 }
  35
  36 static void store_video_mode(void)
  37 {
  38         u16 ax, page;
  39
  40         /* N.B.: the saving of the video page here is a bit silly,
  41            since we pretty much assume page 0 everywhere. */
  42         ax = 0x0f00;
  43         asm(INT10
  44             : "+a" (ax), "=b" (page)
  45             : : "ecx", "edx", "esi", "edi");
  46
  47         /* Not all BIOSes are clean with respect to the top bit */
  48         boot_params.screen_info.orig_video_mode = ax & 0x7f;
  49         boot_params.screen_info.orig_video_page = page >> 8;
  50 }
  51
  52 /*
  53  * Store the video mode parameters for later usage by the kernel.
  54  * This is done by asking the BIOS except for the rows/columns
  55  * parameters in the default 80x25 mode -- these are set directly,
  56  * because some very obscure BIOSes supply insane values.
  57  */
  58 static void store_mode_params(void)
  59 {
  60         u16 font_size;
  61         int x, y;
  62
  63         /* For graphics mode, it is up to the mode-setting driver
  64            (currently only video-vesa.c) to store the parameters */
  65         if (graphic_mode)
  66                 return;
  67
  68         store_cursor_position();
  69         store_video_mode();
  70
  71         if (boot_params.screen_info.orig_video_mode == 0x07) {
  72                 /* MDA, HGC, or VGA in monochrome mode */
  73                 video_segment = 0xb000;
  74         } else {
  75                 /* CGA, EGA, VGA and so forth */
  76                 video_segment = 0xb800;
  77         }
  78
  79         set_fs(0);
  80         font_size = rdfs16(0x485); /* Font size, BIOS area */
  81         boot_params.screen_info.orig_video_points = font_size;
  82
  83         x = rdfs16(0x44a);
  84         y = (adapter == ADAPTER_CGA) ? 25 : rdfs8(0x484)+1;
  85
  86         if (force_x)
  87                 x = force_x;
  88         if (force_y)
  89                 y = force_y;
  90
  91         boot_params.screen_info.orig_video_cols  = x;
  92         boot_params.screen_info.orig_video_lines = y;
  93 }
  94
  95 static unsigned int get_entry(void)
  96 {
  97         char entry_buf[4];
  98         int i, len = 0;
  99         int key;
 100         unsigned int v;
 101
 102         do {
 103                 key = getchar();
 104
 105                 if (key == '\b') {
 106                         if (len > 0) {
 107                                 puts("\b \b");
 108                                 len--;
 109                         }
 110                 } else if ((key >= '0' && key <= '9') ||
 111                            (key >= 'A' && key <= 'Z') ||
 112                            (key >= 'a' && key <= 'z')) {
 113                         if (len < sizeof entry_buf) {
 114                                 entry_buf[len++] = key;
 115                                 putchar(key);
 116                         }
 117                 }
 118         } while (key != '\r');
 119         putchar('\n');
 120
 121         if (len == 0)
 122                 return VIDEO_CURRENT_MODE; /* Default */
 123
 124         v = 0;
 125         for (i = 0; i < len; i++) {
 126                 v <<= 4;
 127                 key = entry_buf[i] | 0x20;
 128                 v += (key > '9') ? key-'a'+10 : key-'0';
 129         }
 130
 131         return v;
 132 }
 133
 134 static void display_menu(void)
 135 {
 136         struct card_info *card;
 137         struct mode_info *mi;
 138         char ch;
 139         int i;
 140         int nmodes;
 141         int modes_per_line;
 142         int col;
 143
 144         nmodes = 0;
 145         for (card = video_cards; card < video_cards_end; card++)
 146                 nmodes += card->nmodes;
 147
 148         modes_per_line = 1;
 149         if (nmodes >= 20)
 150                 modes_per_line = 3;
 151
 152         for (col = 0; col < modes_per_line; col++)
 153                 puts("Mode: Resolution:  Type: ");
 154         putchar('\n');
 155
 156         col = 0;
 157         ch = '0';
 158         for (card = video_cards; card < video_cards_end; card++) {
 159                 mi = card->modes;
 160                 for (i = 0; i < card->nmodes; i++, mi++) {
 161                         char resbuf[32];
 162                         int visible = mi->x && mi->y;
 163                         u16 mode_id = mi->mode ? mi->mode :
 164                                 (mi->y << 8)+mi->x;
 165
 166                         if (!visible)
 167                                 continue; /* Hidden mode */
 168
 169                         if (mi->depth)
 170                                 sprintf(resbuf, "%dx%d", mi->y, mi->depth);
 171                         else
 172                                 sprintf(resbuf, "%d", mi->y);
 173
 174                         printf("%c %03X %4dx%-7s %-6s",
 175                                ch, mode_id, mi->x, resbuf, card->card_name);
 176                         col++;
 177                         if (col >= modes_per_line) {
 178                                 putchar('\n');
 179                                 col = 0;
 180                         }
 181
 182                         if (ch == '9')
 183                                 ch = 'a';
 184                         else if (ch == 'z' || ch == ' ')
 185                                 ch = ' '; /* Out of keys... */
 186                         else
 187                                 ch++;
 188                 }
 189         }
 190         if (col)
 191                 putchar('\n');
 192 }
 193
 194 #define H(x)    ((x)-'a'+10)
 195 #define SCAN    ((H('s')<<12)+(H('c')<<8)+(H('a')<<4)+H('n'))
 196
 197 static unsigned int mode_menu(void)
 198 {
 199         int key;
 200         unsigned int sel;
 201
 202         puts("Press <ENTER> to see video modes available, "
 203              "<SPACE> to continue, or wait 30 sec\n");
 204
 205         kbd_flush();
 206         while (1) {
 207                 key = getchar_timeout();
 208                 if (key == ' ' || key == 0)
 209                         return VIDEO_CURRENT_MODE; /* Default */
 210                 if (key == '\r')
 211                         break;
 212                 putchar('\a');  /* Beep! */
 213         }
 214
 215
 216         for (;;) {
 217                 display_menu();
 218
 219                 puts("Enter a video mode or \"scan\" to scan for "
 220                      "additional modes: ");
 221                 sel = get_entry();
 222                 if (sel != SCAN)
 223                         return sel;
 224
 225                 probe_cards(1);
 226         }
 227 }
 228
 229 #ifdef CONFIG_VIDEO_RETAIN
 230 /* Save screen content to the heap */
 231 struct saved_screen {
 232         int x, y;
 233         int curx, cury;
 234         u16 *data;
 235 } saved;
 236
 237 static void save_screen(void)
 238 {
 239         /* Should be called after store_mode_params() */
 240         saved.x = boot_params.screen_info.orig_video_cols;
 241         saved.y = boot_params.screen_info.orig_video_lines;
 242         saved.curx = boot_params.screen_info.orig_x;
 243         saved.cury = boot_params.screen_info.orig_y;
 244
 245         if (!heap_free(saved.x*saved.y*sizeof(u16)+512))
 246                 return;         /* Not enough heap to save the screen */
 247
 248         saved.data = GET_HEAP(u16, saved.x*saved.y);
 249
 250         set_fs(video_segment);
 251         copy_from_fs(saved.data, 0, saved.x*saved.y*sizeof(u16));
 252 }
 253
 254 static void restore_screen(void)
 255 {
 256         /* Should be called after store_mode_params() */
 257         int xs = boot_params.screen_info.orig_video_cols;
 258         int ys = boot_params.screen_info.orig_video_lines;
 259         int y;
 260         addr_t dst = 0;
 261         u16 *src = saved.data;
 262         u16 ax, bx, dx;
 263
 264         if (graphic_mode)
 265                 return;         /* Can't restore onto a graphic mode */
 266
 267         if (!src)
 268                 return;         /* No saved screen contents */
 269
 270         /* Restore screen contents */
 271
 272         set_fs(video_segment);
 273         for (y = 0; y < ys; y++) {
 274                 int npad;
 275
 276                 if (y < saved.y) {
 277                         int copy = (xs < saved.x) ? xs : saved.x;
 278                         copy_to_fs(dst, src, copy*sizeof(u16));
 279                         dst += copy*sizeof(u16);
 280                         src += saved.x;
 281                         npad = (xs < saved.x) ? 0 : xs-saved.x;
 282                 } else {
 283                         npad = xs;
 284                 }
 285
 286                 /* Writes "npad" blank characters to
 287                    video_segment:dst and advances dst */
 288                 asm volatile("pushw %%es ; "
 289                              "movw %2,%%es ; "
 290                              "shrw %%cx ; "
 291                              "jnc 1f ; "
 292                              "stosw \n\t"
 293                              "1: rep;stosl ; "
 294                              "popw %%es"
 295                              : "+D" (dst), "+c" (npad)
 296                              : "bdS" (video_segment),
 297                                "a" (0x07200720));
 298         }
 299
 300         /* Restore cursor position */
 301         ax = 0x0200;            /* Set cursor position */
 302         bx = 0;                 /* Page number (<< 8) */
 303         dx = (saved.cury << 8)+saved.curx;
 304         asm volatile(INT10
 305                      : "+a" (ax), "+b" (bx), "+d" (dx)
 306                      : : "ecx", "esi", "edi");
 307 }
 308 #else
 309 #define save_screen()           ((void)0)
 310 #define restore_screen()        ((void)0)
 311 #endif
 312
 313 void set_video(void)
 314 {
 315         u16 mode = boot_params.hdr.vid_mode;
 316
 317         RESET_HEAP();
 318
 319         store_mode_params();
 320         save_screen();
 321         probe_cards(0);
 322
 323         for (;;) {
 324                 if (mode == ASK_VGA)
 325                         mode = mode_menu();
 326
 327                 if (!set_mode(mode))
 328                         break;
 329
 330                 printf("Undefined video mode number: %x\n", mode);
 331                 mode = ASK_VGA;
 332         }
 333         boot_params.hdr.vid_mode = mode;
 334         vesa_store_edid();
 335         store_mode_params();
 336
 337         if (do_restore)
 338                 restore_screen();
 339 }