util-linux/fbset.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini fbset implementation for busybox
   4  *
   5  * Copyright (C) 1999 by Randolph Chung <tausq@debian.org>
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8  *
   9  * This is a from-scratch implementation of fbset; but the de facto fbset
  10  * implementation was a good reference. fbset (original) is released under
  11  * the GPL, and is (c) 1995-1999 by:
  12  *     Geert Uytterhoeven (Geert.Uytterhoeven@cs.kuleuven.ac.be)
  13  */
  14 //config:config FBSET
  15 //config:       bool "fbset (5.8 kb)"
  16 //config:       default y
  17 //config:       select PLATFORM_LINUX
  18 //config:       help
  19 //config:         fbset is used to show or change the settings of a Linux frame buffer
  20 //config:         device. The frame buffer device provides a simple and unique
  21 //config:         interface to access a graphics display. Enable this option
  22 //config:         if you wish to enable the 'fbset' utility.
  23 //config:
  24 //config:config FEATURE_FBSET_FANCY
  25 //config:       bool "Enable extra options"
  26 //config:       default y
  27 //config:       depends on FBSET
  28 //config:       help
  29 //config:         This option enables extended fbset options, allowing one to set the
  30 //config:         framebuffer size, color depth, etc. interface to access a graphics
  31 //config:         display. Enable this option if you wish to enable extended fbset
  32 //config:         options.
  33 //config:
  34 //config:config FEATURE_FBSET_READMODE
  35 //config:       bool "Enable readmode support"
  36 //config:       default y
  37 //config:       depends on FBSET
  38 //config:       help
  39 //config:         This option allows fbset to read the video mode database stored by
  40 //config:         default as /etc/fb.modes, which can be used to set frame buffer
  41 //config:         device to pre-defined video modes.
  42
  43 //applet:IF_FBSET(APPLET(fbset, BB_DIR_USR_SBIN, BB_SUID_DROP))
  44
  45 //kbuild:lib-$(CONFIG_FBSET) += fbset.o
  46
  47 //usage:#define fbset_trivial_usage
  48 //usage:       "[OPTIONS] [MODE]"
  49 //usage:#define fbset_full_usage "\n\n"
  50 //usage:       "Show and modify frame buffer settings"
  51 //usage:
  52 //usage:#define fbset_example_usage
  53 //usage:       "$ fbset\n"
  54 //usage:       "mode \"1024x768-76\"\n"
  55 //usage:       "        # D: 78.653 MHz, H: 59.949 kHz, V: 75.694 Hz\n"
  56 //usage:       "        geometry 1024 768 1024 768 16\n"
  57 //usage:       "        timings 12714 128 32 16 4 128 4\n"
  58 //usage:       "        accel false\n"
  59 //usage:       "        rgba 5/11,6/5,5/0,0/0\n"
  60 //usage:       "endmode\n"
  61
  62 #include "libbb.h"
  63
  64 #define DEFAULTFBDEV  FB_0
  65 #define DEFAULTFBMODE "/etc/fb.modes"
  66
  67 /* Stuff stolen from the kernel's fb.h */
  68 #define FB_ACTIVATE_ALL 64
  69 enum {
  70         FBIOGET_VSCREENINFO = 0x4600,
  71         FBIOPUT_VSCREENINFO = 0x4601
  72 };
  73
  74 struct fb_bitfield {
  75         uint32_t offset;                /* beginning of bitfield */
  76         uint32_t length;                /* length of bitfield */
  77         uint32_t msb_right;             /* !=0: Most significant bit is right */
  78 };
  79 struct fb_var_screeninfo {
  80         uint32_t xres;                  /* visible resolution */
  81         uint32_t yres;
  82         uint32_t xres_virtual;          /* virtual resolution */
  83         uint32_t yres_virtual;
  84         uint32_t xoffset;               /* offset from virtual to visible */
  85         uint32_t yoffset;               /* resolution */
  86
  87         uint32_t bits_per_pixel;
  88         uint32_t grayscale;             /* !=0 Graylevels instead of colors */
  89
  90         struct fb_bitfield red;         /* bitfield in fb mem if true color, */
  91         struct fb_bitfield green;       /* else only length is significant */
  92         struct fb_bitfield blue;
  93         struct fb_bitfield transp;      /* transparency */
  94
  95         uint32_t nonstd;                /* !=0 Non standard pixel format */
  96
  97         uint32_t activate;              /* see FB_ACTIVATE_x */
  98
  99         uint32_t height;                /* height of picture in mm */
 100         uint32_t width;                 /* width of picture in mm */
 101
 102         uint32_t accel_flags;           /* acceleration flags (hints) */
 103
 104         /* Timing: All values in pixclocks, except pixclock (of course) */
 105         uint32_t pixclock;              /* pixel clock in ps (pico seconds) */
 106         uint32_t left_margin;           /* time from sync to picture */
 107         uint32_t right_margin;          /* time from picture to sync */
 108         uint32_t upper_margin;          /* time from sync to picture */
 109         uint32_t lower_margin;
 110         uint32_t hsync_len;             /* length of horizontal sync */
 111         uint32_t vsync_len;             /* length of vertical sync */
 112         uint32_t sync;                  /* see FB_SYNC_x */
 113         uint32_t vmode;                 /* see FB_VMODE_x */
 114         uint32_t reserved[6];           /* Reserved for future compatibility */
 115 };
 116
 117 static void copy_if_gt0(uint32_t *src, uint32_t *dst, unsigned cnt)
 118 {
 119         do {
 120                 if ((int32_t) *src > 0)
 121                         *dst = *src;
 122                 src++;
 123                 dst++;
 124         } while (--cnt);
 125 }
 126
 127 static NOINLINE void copy_changed_values(
 128                 struct fb_var_screeninfo *base,
 129                 struct fb_var_screeninfo *set)
 130 {
 131         //if ((int32_t) set->xres > 0) base->xres = set->xres;
 132         //if ((int32_t) set->yres > 0) base->yres = set->yres;
 133         //if ((int32_t) set->xres_virtual > 0)   base->xres_virtual = set->xres_virtual;
 134         //if ((int32_t) set->yres_virtual > 0)   base->yres_virtual = set->yres_virtual;
 135         copy_if_gt0(&set->xres, &base->xres, 4);
 136
 137         if ((int32_t) set->bits_per_pixel > 0) base->bits_per_pixel = set->bits_per_pixel;
 138         //copy_if_gt0(&set->bits_per_pixel, &base->bits_per_pixel, 1);
 139
 140         //if ((int32_t) set->pixclock > 0)       base->pixclock = set->pixclock;
 141         //if ((int32_t) set->left_margin > 0)    base->left_margin = set->left_margin;
 142         //if ((int32_t) set->right_margin > 0)   base->right_margin = set->right_margin;
 143         //if ((int32_t) set->upper_margin > 0)   base->upper_margin = set->upper_margin;
 144         //if ((int32_t) set->lower_margin > 0)   base->lower_margin = set->lower_margin;
 145         //if ((int32_t) set->hsync_len > 0) base->hsync_len = set->hsync_len;
 146         //if ((int32_t) set->vsync_len > 0) base->vsync_len = set->vsync_len;
 147         //if ((int32_t) set->sync > 0)  base->sync = set->sync;
 148         //if ((int32_t) set->vmode > 0) base->vmode = set->vmode;
 149         copy_if_gt0(&set->pixclock, &base->pixclock, 9);
 150 }
 151
 152
 153 enum {
 154         CMD_FB = 1,
 155         CMD_DB = 2,
 156         CMD_GEOMETRY = 3,
 157         CMD_TIMING = 4,
 158         CMD_ACCEL = 5,
 159         CMD_HSYNC = 6,
 160         CMD_VSYNC = 7,
 161         CMD_LACED = 8,
 162         CMD_DOUBLE = 9,
 163 /*      CMD_XCOMPAT =     10, */
 164         CMD_ALL = 11,
 165         CMD_INFO = 12,
 166         CMD_SHOW = 13,
 167         CMD_CHANGE = 14,
 168
 169 #if ENABLE_FEATURE_FBSET_FANCY
 170         CMD_XRES = 100,
 171         CMD_YRES = 101,
 172         CMD_VXRES = 102,
 173         CMD_VYRES = 103,
 174         CMD_DEPTH = 104,
 175         CMD_MATCH = 105,
 176         CMD_PIXCLOCK = 106,
 177         CMD_LEFT = 107,
 178         CMD_RIGHT = 108,
 179         CMD_UPPER = 109,
 180         CMD_LOWER = 110,
 181         CMD_HSLEN = 111,
 182         CMD_VSLEN = 112,
 183         CMD_CSYNC = 113,
 184         CMD_GSYNC = 114,
 185         CMD_EXTSYNC = 115,
 186         CMD_BCAST = 116,
 187         CMD_RGBA = 117,
 188         CMD_STEP = 118,
 189         CMD_MOVE = 119,
 190 #endif
 191 };
 192
 193 static const struct cmdoptions_t {
 194         const char name[9];
 195         const unsigned char param_count;
 196         const unsigned char code;
 197 } g_cmdoptions[] = {
 198         /*"12345678" + NUL */
 199 //TODO: convert to index_in_strings()
 200         { "fb"      , 1, CMD_FB       },
 201         { "db"      , 1, CMD_DB       },
 202         { "a"       , 0, CMD_ALL      },
 203         { "i"       , 0, CMD_INFO     },
 204         { "g"       , 5, CMD_GEOMETRY },
 205         { "t"       , 7, CMD_TIMING   },
 206         { "accel"   , 1, CMD_ACCEL    },
 207         { "hsync"   , 1, CMD_HSYNC    },
 208         { "vsync"   , 1, CMD_VSYNC    },
 209         { "laced"   , 1, CMD_LACED    },
 210         { "double"  , 1, CMD_DOUBLE   },
 211         { "show"    , 0, CMD_SHOW     },
 212         { "s"       , 0, CMD_SHOW     },
 213 #if ENABLE_FEATURE_FBSET_FANCY
 214         { "all"     , 0, CMD_ALL      },
 215         { "xres"    , 1, CMD_XRES     },
 216         { "yres"    , 1, CMD_YRES     },
 217         { "vxres"   , 1, CMD_VXRES    },
 218         { "vyres"   , 1, CMD_VYRES    },
 219         { "depth"   , 1, CMD_DEPTH    },
 220         { "match"   , 0, CMD_MATCH    },
 221         { "geometry", 5, CMD_GEOMETRY },
 222         { "pixclock", 1, CMD_PIXCLOCK },
 223         { "left"    , 1, CMD_LEFT     },
 224         { "right"   , 1, CMD_RIGHT    },
 225         { "upper"   , 1, CMD_UPPER    },
 226         { "lower"   , 1, CMD_LOWER    },
 227         { "hslen"   , 1, CMD_HSLEN    },
 228         { "vslen"   , 1, CMD_VSLEN    },
 229         { "timings" , 7, CMD_TIMING   },
 230         { "csync"   , 1, CMD_CSYNC    },
 231         { "gsync"   , 1, CMD_GSYNC    },
 232         { "extsync" , 1, CMD_EXTSYNC  },
 233         { "bcast"   , 1, CMD_BCAST    },
 234         { "rgba"    , 1, CMD_RGBA     },
 235         { "step"    , 1, CMD_STEP     },
 236         { "move"    , 1, CMD_MOVE     },
 237 #endif
 238 };
 239
 240 /* taken from linux/fb.h */
 241 enum {
 242         FB_SYNC_HOR_HIGH_ACT = 1,       /* horizontal sync high active */
 243         FB_SYNC_VERT_HIGH_ACT = 2,      /* vertical sync high active */
 244 #if ENABLE_FEATURE_FBSET_READMODE
 245         FB_VMODE_INTERLACED = 1,        /* interlaced */
 246         FB_VMODE_DOUBLE = 2,            /* double scan */
 247         FB_SYNC_EXT = 4,                /* external sync */
 248         FB_SYNC_COMP_HIGH_ACT = 8,      /* composite sync high active */
 249 #endif
 250 };
 251
 252 #if ENABLE_FEATURE_FBSET_READMODE
 253 static void ss(uint32_t *x, uint32_t flag, char *buf, const char *what)
 254 {
 255         if (strcmp(buf, what) == 0)
 256                 *x &= ~flag;
 257         else
 258                 *x |= flag;
 259 }
 260
 261 /* Mode db file contains mode definitions like this:
 262  * mode "800x600-48-lace"
 263  *     # D: 36.00 MHz, H: 33.835 kHz, V: 96.39 Hz
 264  *     geometry 800 600 800 600 8
 265  *     timings 27778 56 80 79 11 128 12
 266  *     laced true
 267  *     hsync high
 268  *     vsync high
 269  * endmode
 270  */
 271 static int read_mode_db(struct fb_var_screeninfo *base, const char *fn,
 272                                         const char *mode)
 273 {
 274         char *token[2], *p, *s;
 275         parser_t *parser = config_open(fn);
 276
 277         while (config_read(parser, token, 2, 1, "# \t\r", PARSE_NORMAL)) {
 278                 if (strcmp(token[0], "mode") != 0 || !token[1])
 279                         continue;
 280                 p = strstr(token[1], mode);
 281                 if (!p)
 282                         continue;
 283                 s = p + strlen(mode);
 284                 //bb_error_msg("CHECK[%s][%s][%d]", mode, p-1, *s);
 285                 /* exact match? */
 286                 if (((!*s || isspace(*s)) && '"' != s[-1]) /* end-of-token */
 287                  || ('"' == *s && '"' == p[-1]) /* ends with " but starts with " too! */
 288                 ) {
 289                         //bb_error_msg("FOUND[%s][%s][%s][%d]", token[1], p, mode, isspace(*s));
 290                         break;
 291                 }
 292         }
 293
 294         if (!token[0])
 295                 return 0;
 296
 297         while (config_read(parser, token, 2, 1, "# \t", PARSE_NORMAL)) {
 298                 int i;
 299
 300 //bb_error_msg("???[%s][%s]", token[0], token[1]);
 301                 if (strcmp(token[0], "endmode") == 0) {
 302 //bb_error_msg("OK[%s]", mode);
 303                         return 1;
 304                 }
 305                 p = token[1];
 306                 i = index_in_strings(
 307                         "geometry\0timings\0interlaced\0double\0vsync\0hsync\0csync\0extsync\0rgba\0",
 308                         token[0]);
 309                 switch (i) {
 310                 case 0:
 311                         if (sizeof(int) == sizeof(base->xres)) {
 312                                 sscanf(p, "%d %d %d %d %d",
 313                                         &base->xres, &base->yres,
 314                                         &base->xres_virtual, &base->yres_virtual,
 315                                         &base->bits_per_pixel);
 316                         } else {
 317                                 int base_xres, base_yres;
 318                                 int base_xres_virtual, base_yres_virtual;
 319                                 int base_bits_per_pixel;
 320                                 sscanf(p, "%d %d %d %d %d",
 321                                         &base_xres, &base_yres,
 322                                         &base_xres_virtual, &base_yres_virtual,
 323                                         &base_bits_per_pixel);
 324                                 base->xres = base_xres;
 325                                 base->yres = base_yres;
 326                                 base->xres_virtual = base_xres_virtual;
 327                                 base->yres_virtual = base_yres_virtual;
 328                                 base->bits_per_pixel = base_bits_per_pixel;
 329                         }
 330 //bb_error_msg("GEO[%s]", p);
 331                         break;
 332                 case 1:
 333                         if (sizeof(int) == sizeof(base->xres)) {
 334                                 sscanf(p, "%d %d %d %d %d %d %d",
 335                                         &base->pixclock,
 336                                         &base->left_margin, &base->right_margin,
 337                                         &base->upper_margin, &base->lower_margin,
 338                                         &base->hsync_len, &base->vsync_len);
 339                         } else {
 340                                 int base_pixclock;
 341                                 int base_left_margin, base_right_margin;
 342                                 int base_upper_margin, base_lower_margin;
 343                                 int base_hsync_len, base_vsync_len;
 344                                 sscanf(p, "%d %d %d %d %d %d %d",
 345                                         &base_pixclock,
 346                                         &base_left_margin, &base_right_margin,
 347                                         &base_upper_margin, &base_lower_margin,
 348                                         &base_hsync_len, &base_vsync_len);
 349                                 base->pixclock = base_pixclock;
 350                                 base->left_margin = base_left_margin;
 351                                 base->right_margin = base_right_margin;
 352                                 base->upper_margin = base_upper_margin;
 353                                 base->lower_margin = base_lower_margin;
 354                                 base->hsync_len = base_hsync_len;
 355                                 base->vsync_len = base_vsync_len;
 356                         }
 357 //bb_error_msg("TIM[%s]", p);
 358                         break;
 359                 case 2:
 360                 case 3: {
 361                         static const uint32_t syncs[] = {FB_VMODE_INTERLACED, FB_VMODE_DOUBLE};
 362                         ss(&base->vmode, syncs[i-2], p, "false");
 363 //bb_error_msg("VMODE[%s]", p);
 364                         break;
 365                 }
 366                 case 4:
 367                 case 5:
 368                 case 6: {
 369                         static const uint32_t syncs[] = {FB_SYNC_VERT_HIGH_ACT, FB_SYNC_HOR_HIGH_ACT, FB_SYNC_COMP_HIGH_ACT};
 370                         ss(&base->sync, syncs[i-4], p, "low");
 371 //bb_error_msg("SYNC[%s]", p);
 372                         break;
 373                 }
 374                 case 7:
 375                         ss(&base->sync, FB_SYNC_EXT, p, "false");
 376 //bb_error_msg("EXTSYNC[%s]", p);
 377                         break;
 378                 case 8: {
 379                         int red_offset, red_length;
 380                         int green_offset, green_length;
 381                         int blue_offset, blue_length;
 382                         int transp_offset, transp_length;
 383
 384                         sscanf(p, "%d/%d,%d/%d,%d/%d,%d/%d",
 385                                 &red_length, &red_offset,
 386                                 &green_length, &green_offset,
 387                                 &blue_length, &blue_offset,
 388                                 &transp_length, &transp_offset);
 389                         base->red.offset = red_offset;
 390                         base->red.length = red_length;
 391                         base->red.msb_right = 0;
 392                         base->green.offset = green_offset;
 393                         base->green.length = green_length;
 394                         base->green.msb_right = 0;
 395                         base->blue.offset = blue_offset;
 396                         base->blue.length = blue_length;
 397                         base->blue.msb_right = 0;
 398                         base->transp.offset = transp_offset;
 399                         base->transp.length = transp_length;
 400                         base->transp.msb_right = 0;
 401                 }
 402                 }
 403         }
 404         return 0;
 405 }
 406 #endif
 407
 408 static NOINLINE void showmode(struct fb_var_screeninfo *v)
 409 {
 410         double drate = 0, hrate = 0, vrate = 0;
 411
 412         if (v->pixclock) {
 413                 drate = 1e12 / v->pixclock;
 414                 hrate = drate / (v->left_margin + v->xres + v->right_margin + v->hsync_len);
 415                 vrate = hrate / (v->upper_margin + v->yres + v->lower_margin + v->vsync_len);
 416         }
 417         printf("\nmode \"%ux%u-%u\"\n"
 418 #if ENABLE_FEATURE_FBSET_FANCY
 419         "\t# D: %.3f MHz, H: %.3f kHz, V: %.3f Hz\n"
 420 #endif
 421         "\tgeometry %u %u %u %u %u\n"
 422         "\ttimings %u %u %u %u %u %u %u\n"
 423         "\taccel %s\n"
 424         "\trgba %u/%u,%u/%u,%u/%u,%u/%u\n"
 425         "endmode\n\n",
 426                 v->xres, v->yres, (int) (vrate + 0.5),
 427 #if ENABLE_FEATURE_FBSET_FANCY
 428                 drate / 1e6, hrate / 1e3, vrate,
 429 #endif
 430                 v->xres, v->yres, v->xres_virtual, v->yres_virtual, v->bits_per_pixel,
 431                 v->pixclock, v->left_margin, v->right_margin, v->upper_margin, v->lower_margin,
 432                         v->hsync_len, v->vsync_len,
 433                 (v->accel_flags > 0 ? "true" : "false"),
 434                 v->red.length, v->red.offset, v->green.length, v->green.offset,
 435                         v->blue.length, v->blue.offset, v->transp.length, v->transp.offset);
 436 }
 437
 438 int fbset_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 439 int fbset_main(int argc, char **argv)
 440 {
 441         enum {
 442                 OPT_CHANGE   = (1 << 0),
 443                 OPT_SHOW     = (1 << 1),
 444                 OPT_READMODE = (1 << 2),
 445                 OPT_ALL      = (1 << 3),
 446         };
 447         struct fb_var_screeninfo var_old, var_set;
 448         int fh, i;
 449         unsigned options = 0;
 450
 451         const char *fbdev = DEFAULTFBDEV;
 452         IF_FEATURE_FBSET_READMODE(const char *modefile = DEFAULTFBMODE;)
 453         char *thisarg;
 454         char *mode = mode; /* for compiler */
 455
 456         memset(&var_set, 0xff, sizeof(var_set)); /* set all to -1 */
 457
 458         /* parse cmd args.... why do they have to make things so difficult? */
 459         argv++;
 460         argc--;
 461         for (; argc > 0 && (thisarg = *argv) != NULL; argc--, argv++) {
 462                 if (thisarg[0] != '-') {
 463                         if (!ENABLE_FEATURE_FBSET_READMODE || argc != 1)
 464                                 bb_show_usage();
 465                         mode = thisarg;
 466                         options |= OPT_READMODE;
 467                         goto contin;
 468                 }
 469                 for (i = 0; i < ARRAY_SIZE(g_cmdoptions); i++) {
 470                         if (strcmp(thisarg + 1, g_cmdoptions[i].name) != 0)
 471                                 continue;
 472                         if (argc <= g_cmdoptions[i].param_count)
 473                                 bb_show_usage();
 474
 475                         switch (g_cmdoptions[i].code) {
 476                         case CMD_FB:
 477                                 fbdev = argv[1];
 478                                 break;
 479                         case CMD_DB:
 480                                 IF_FEATURE_FBSET_READMODE(modefile = argv[1];)
 481                                 break;
 482                         case CMD_ALL:
 483                                 options |= OPT_ALL;
 484                                 break;
 485                         case CMD_SHOW:
 486                                 options |= OPT_SHOW;
 487                                 break;
 488                         case CMD_GEOMETRY:
 489                                 var_set.xres = xatou32(argv[1]);
 490                                 var_set.yres = xatou32(argv[2]);
 491                                 var_set.xres_virtual = xatou32(argv[3]);
 492                                 var_set.yres_virtual = xatou32(argv[4]);
 493                                 var_set.bits_per_pixel = xatou32(argv[5]);
 494                                 break;
 495                         case CMD_TIMING:
 496                                 var_set.pixclock = xatou32(argv[1]);
 497                                 var_set.left_margin = xatou32(argv[2]);
 498                                 var_set.right_margin = xatou32(argv[3]);
 499                                 var_set.upper_margin = xatou32(argv[4]);
 500                                 var_set.lower_margin = xatou32(argv[5]);
 501                                 var_set.hsync_len = xatou32(argv[6]);
 502                                 var_set.vsync_len = xatou32(argv[7]);
 503                                 break;
 504                         case CMD_ACCEL:
 505                                 break;
 506                         case CMD_HSYNC:
 507                                 var_set.sync |= FB_SYNC_HOR_HIGH_ACT;
 508                                 break;
 509                         case CMD_VSYNC:
 510                                 var_set.sync |= FB_SYNC_VERT_HIGH_ACT;
 511                                 break;
 512 #if ENABLE_FEATURE_FBSET_FANCY
 513                         case CMD_XRES:
 514                                 var_set.xres = xatou32(argv[1]);
 515                                 break;
 516                         case CMD_YRES:
 517                                 var_set.yres = xatou32(argv[1]);
 518                                 break;
 519                         case CMD_DEPTH:
 520                                 var_set.bits_per_pixel = xatou32(argv[1]);
 521                                 break;
 522 #endif
 523                         }
 524                         switch (g_cmdoptions[i].code) {
 525                         case CMD_FB:
 526                         case CMD_DB:
 527                         case CMD_ALL:
 528                         case CMD_SHOW:
 529                                 break;
 530                         default:
 531                                 /* other commands imply changes */
 532                                 options |= OPT_CHANGE;
 533                         }
 534                         argc -= g_cmdoptions[i].param_count;
 535                         argv += g_cmdoptions[i].param_count;
 536                         goto contin;
 537                 }
 538                 bb_show_usage();
 539  contin: ;
 540         }
 541
 542         fh = xopen(fbdev, O_RDONLY);
 543         xioctl(fh, FBIOGET_VSCREENINFO, &var_old);
 544
 545         if (options & OPT_READMODE) {
 546 #if ENABLE_FEATURE_FBSET_READMODE
 547                 if (!read_mode_db(&var_old, modefile, mode)) {
 548                         bb_error_msg_and_die("unknown video mode '%s'", mode);
 549                 }
 550                 options |= OPT_CHANGE;
 551 #endif
 552         }
 553
 554         if (options & OPT_CHANGE) {
 555                 copy_changed_values(&var_old, &var_set);
 556                 if (options & OPT_ALL)
 557                         var_old.activate = FB_ACTIVATE_ALL;
 558                 xioctl(fh, FBIOPUT_VSCREENINFO, &var_old);
 559         }
 560
 561         if (options == 0 || (options & OPT_SHOW))
 562                 showmode(&var_old);
 563
 564         if (ENABLE_FEATURE_CLEAN_UP)
 565                 close(fh);
 566
 567         return EXIT_SUCCESS;
 568 }