linux/arch/x86/boot/video.c
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   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 * Select video mode
  13 */
  14
  15#include "boot.h"
  16#include "video.h"
  17#include "vesa.h"
  18
  19static void store_cursor_position(void)
  20{
  21        u16 curpos;
  22        u16 ax, bx;
  23
  24        ax = 0x0300;
  25        bx = 0;
  26        asm(INT10
  27            : "=d" (curpos), "+a" (ax), "+b" (bx)
  28            : : "ecx", "esi", "edi");
  29
  30        boot_params.screen_info.orig_x = curpos;
  31        boot_params.screen_info.orig_y = curpos >> 8;
  32}
  33
  34static void store_video_mode(void)
  35{
  36        u16 ax, page;
  37
  38        /* N.B.: the saving of the video page here is a bit silly,
  39           since we pretty much assume page 0 everywhere. */
  40        ax = 0x0f00;
  41        asm(INT10
  42            : "+a" (ax), "=b" (page)
  43            : : "ecx", "edx", "esi", "edi");
  44
  45        /* Not all BIOSes are clean with respect to the top bit */
  46        boot_params.screen_info.orig_video_mode = ax & 0x7f;
  47        boot_params.screen_info.orig_video_page = page >> 8;
  48}
  49
  50/*
  51 * Store the video mode parameters for later usage by the kernel.
  52 * This is done by asking the BIOS except for the rows/columns
  53 * parameters in the default 80x25 mode -- these are set directly,
  54 * because some very obscure BIOSes supply insane values.
  55 */
  56static void store_mode_params(void)
  57{
  58        u16 font_size;
  59        int x, y;
  60
  61        /* For graphics mode, it is up to the mode-setting driver
  62           (currently only video-vesa.c) to store the parameters */
  63        if (graphic_mode)
  64                return;
  65
  66        store_cursor_position();
  67        store_video_mode();
  68
  69        if (boot_params.screen_info.orig_video_mode == 0x07) {
  70                /* MDA, HGC, or VGA in monochrome mode */
  71                video_segment = 0xb000;
  72        } else {
  73                /* CGA, EGA, VGA and so forth */
  74                video_segment = 0xb800;
  75        }
  76
  77        set_fs(0);
  78        font_size = rdfs16(0x485); /* Font size, BIOS area */
  79        boot_params.screen_info.orig_video_points = font_size;
  80
  81        x = rdfs16(0x44a);
  82        y = (adapter == ADAPTER_CGA) ? 25 : rdfs8(0x484)+1;
  83
  84        if (force_x)
  85                x = force_x;
  86        if (force_y)
  87                y = force_y;
  88
  89        boot_params.screen_info.orig_video_cols  = x;
  90        boot_params.screen_info.orig_video_lines = y;
  91}
  92
  93static unsigned int get_entry(void)
  94{
  95        char entry_buf[4];
  96        int i, len = 0;
  97        int key;
  98        unsigned int v;
  99
 100        do {
 101                key = getchar();
 102
 103                if (key == '\b') {
 104                        if (len > 0) {
 105                                puts("\b \b");
 106                                len--;
 107                        }
 108                } else if ((key >= '0' && key <= '9') ||
 109                           (key >= 'A' && key <= 'Z') ||
 110                           (key >= 'a' && key <= 'z')) {
 111                        if (len < sizeof entry_buf) {
 112                                entry_buf[len++] = key;
 113                                putchar(key);
 114                        }
 115                }
 116        } while (key != '\r');
 117        putchar('\n');
 118
 119        if (len == 0)
 120                return VIDEO_CURRENT_MODE; /* Default */
 121
 122        v = 0;
 123        for (i = 0; i < len; i++) {
 124                v <<= 4;
 125                key = entry_buf[i] | 0x20;
 126                v += (key > '9') ? key-'a'+10 : key-'0';
 127        }
 128
 129        return v;
 130}
 131
 132static void display_menu(void)
 133{
 134        struct card_info *card;
 135        struct mode_info *mi;
 136        char ch;
 137        int i;
 138        int nmodes;
 139        int modes_per_line;
 140        int col;
 141
 142        nmodes = 0;
 143        for (card = video_cards; card < video_cards_end; card++)
 144                nmodes += card->nmodes;
 145
 146        modes_per_line = 1;
 147        if (nmodes >= 20)
 148                modes_per_line = 3;
 149
 150        for (col = 0; col < modes_per_line; col++)
 151                puts("Mode: Resolution:  Type: ");
 152        putchar('\n');
 153
 154        col = 0;
 155        ch = '0';
 156        for (card = video_cards; card < video_cards_end; card++) {
 157                mi = card->modes;
 158                for (i = 0; i < card->nmodes; i++, mi++) {
 159                        char resbuf[32];
 160                        int visible = mi->x && mi->y;
 161                        u16 mode_id = mi->mode ? mi->mode :
 162                                (mi->y << 8)+mi->x;
 163
 164                        if (!visible)
 165                                continue; /* Hidden mode */
 166
 167                        if (mi->depth)
 168                                sprintf(resbuf, "%dx%d", mi->y, mi->depth);
 169                        else
 170                                sprintf(resbuf, "%d", mi->y);
 171
 172                        printf("%c %03X %4dx%-7s %-6s",
 173                               ch, mode_id, mi->x, resbuf, card->card_name);
 174                        col++;
 175                        if (col >= modes_per_line) {
 176                                putchar('\n');
 177                                col = 0;
 178                        }
 179
 180                        if (ch == '9')
 181                                ch = 'a';
 182                        else if (ch == 'z' || ch == ' ')
 183                                ch = ' '; /* Out of keys... */
 184                        else
 185                                ch++;
 186                }
 187        }
 188        if (col)
 189                putchar('\n');
 190}
 191
 192#define H(x)    ((x)-'a'+10)
 193#define SCAN    ((H('s')<<12)+(H('c')<<8)+(H('a')<<4)+H('n'))
 194
 195static unsigned int mode_menu(void)
 196{
 197        int key;
 198        unsigned int sel;
 199
 200        puts("Press <ENTER> to see video modes available, "
 201             "<SPACE> to continue, or wait 30 sec\n");
 202
 203        kbd_flush();
 204        while (1) {
 205                key = getchar_timeout();
 206                if (key == ' ' || key == 0)
 207                        return VIDEO_CURRENT_MODE; /* Default */
 208                if (key == '\r')
 209                        break;
 210                putchar('\a');  /* Beep! */
 211        }
 212
 213
 214        for (;;) {
 215                display_menu();
 216
 217                puts("Enter a video mode or \"scan\" to scan for "
 218                     "additional modes: ");
 219                sel = get_entry();
 220                if (sel != SCAN)
 221                        return sel;
 222
 223                probe_cards(1);
 224        }
 225}
 226
 227#ifdef CONFIG_VIDEO_RETAIN
 228/* Save screen content to the heap */
 229struct saved_screen {
 230        int x, y;
 231        int curx, cury;
 232        u16 *data;
 233} saved;
 234
 235static void save_screen(void)
 236{
 237        /* Should be called after store_mode_params() */
 238        saved.x = boot_params.screen_info.orig_video_cols;
 239        saved.y = boot_params.screen_info.orig_video_lines;
 240        saved.curx = boot_params.screen_info.orig_x;
 241        saved.cury = boot_params.screen_info.orig_y;
 242
 243        if (!heap_free(saved.x*saved.y*sizeof(u16)+512))
 244                return;         /* Not enough heap to save the screen */
 245
 246        saved.data = GET_HEAP(u16, saved.x*saved.y);
 247
 248        set_fs(video_segment);
 249        copy_from_fs(saved.data, 0, saved.x*saved.y*sizeof(u16));
 250}
 251
 252static void restore_screen(void)
 253{
 254        /* Should be called after store_mode_params() */
 255        int xs = boot_params.screen_info.orig_video_cols;
 256        int ys = boot_params.screen_info.orig_video_lines;
 257        int y;
 258        addr_t dst = 0;
 259        u16 *src = saved.data;
 260        u16 ax, bx, dx;
 261
 262        if (graphic_mode)
 263                return;         /* Can't restore onto a graphic mode */
 264
 265        if (!src)
 266                return;         /* No saved screen contents */
 267
 268        /* Restore screen contents */
 269
 270        set_fs(video_segment);
 271        for (y = 0; y < ys; y++) {
 272                int npad;
 273
 274                if (y < saved.y) {
 275                        int copy = (xs < saved.x) ? xs : saved.x;
 276                        copy_to_fs(dst, src, copy*sizeof(u16));
 277                        dst += copy*sizeof(u16);
 278                        src += saved.x;
 279                        npad = (xs < saved.x) ? 0 : xs-saved.x;
 280                } else {
 281                        npad = xs;
 282                }
 283
 284                /* Writes "npad" blank characters to
 285                   video_segment:dst and advances dst */
 286                asm volatile("pushw %%es ; "
 287                             "movw %2,%%es ; "
 288                             "shrw %%cx ; "
 289                             "jnc 1f ; "
 290                             "stosw \n\t"
 291                             "1: rep;stosl ; "
 292                             "popw %%es"
 293                             : "+D" (dst), "+c" (npad)
 294                             : "bdS" (video_segment),
 295                               "a" (0x07200720));
 296        }
 297
 298        /* Restore cursor position */
 299        ax = 0x0200;            /* Set cursor position */
 300        bx = 0;                 /* Page number (<< 8) */
 301        dx = (saved.cury << 8)+saved.curx;
 302        asm volatile(INT10
 303                     : "+a" (ax), "+b" (bx), "+d" (dx)
 304                     : : "ecx", "esi", "edi");
 305}
 306#else
 307#define save_screen()           ((void)0)
 308#define restore_screen()        ((void)0)
 309#endif
 310
 311void set_video(void)
 312{
 313        u16 mode = boot_params.hdr.vid_mode;
 314
 315        RESET_HEAP();
 316
 317        store_mode_params();
 318        save_screen();
 319        probe_cards(0);
 320
 321        for (;;) {
 322                if (mode == ASK_VGA)
 323                        mode = mode_menu();
 324
 325                if (!set_mode(mode))
 326                        break;
 327
 328                printf("Undefined video mode number: %x\n", mode);
 329                mode = ASK_VGA;
 330        }
 331        boot_params.hdr.vid_mode = mode;
 332        vesa_store_edid();
 333        store_mode_params();
 334
 335        if (do_restore)
 336                restore_screen();
 337}
 338