/ src / lib / edid.c
edid.c
   1  /* SPDX-License-Identifier: MIT */
   2  
   3  /* this is a pretty robust parser for EDID, and we're tasked with parsing
   4   * an arbitrary panel. We will pass it a raw EDID block and a struct which
   5   * it must fill in with values. The set of values we need is pretty limited
   6   * at present.
   7   */
   8  
   9  #include <assert.h>
  10  #include <commonlib/helpers.h>
  11  #include <console/console.h>
  12  #include <ctype.h>
  13  #include <stdint.h>
  14  #include <string.h>
  15  #include <edid.h>
  16  #include <vbe.h>
  17  
  18  struct edid_context {
  19  	int claims_one_point_oh;
  20  	int claims_one_point_two;
  21  	int claims_one_point_three;
  22  	int claims_one_point_four;
  23  	int nonconformant_digital_display;
  24  	int nonconformant_extension;
  25  	int did_detailed_timing;
  26  	int has_name_descriptor;
  27  	int has_range_descriptor;
  28  	int has_preferred_timing;
  29  	int has_valid_checksum;
  30  	int has_valid_cvt;
  31  	int has_valid_dummy_block;
  32  	int has_valid_week;
  33  	int has_valid_year;
  34  	int has_valid_detailed_blocks;
  35  	int has_valid_extension_count;
  36  	int has_valid_descriptor_ordering;
  37  	int has_valid_descriptor_pad;
  38  	int has_valid_range_descriptor;
  39  	int has_valid_max_dotclock;
  40  	int has_valid_string_termination;
  41  	int manufacturer_name_well_formed;
  42  	int seen_non_detailed_descriptor;
  43  	int warning_excessive_dotclock_correction;
  44  	int warning_zero_preferred_refresh;
  45  	enum edid_status conformant;
  46  };
  47  
  48  /* Stuff that isn't used anywhere but is nice to pretty-print while
  49     we're decoding everything else. */
  50  static struct {
  51  	unsigned int model;
  52  	unsigned int serial;
  53  	unsigned int year;
  54  	unsigned int week;
  55  	unsigned int version[2];
  56  	unsigned int nonconformant;
  57  	unsigned int type;
  58  
  59  	unsigned int x_mm;
  60  	unsigned int y_mm;
  61  
  62  	unsigned int voltage;
  63  	unsigned int sync;
  64  
  65  	const char *syncmethod;
  66  	const char *range_class;
  67  	const char *stereo;
  68  } extra_info;
  69  
  70  static struct edid tmp_edid;
  71  
  72  static int manufacturer_name(unsigned char *x, char *output)
  73  {
  74  	output[0] = ((x[0] & 0x7C) >> 2) + '@';
  75  	output[1] = ((x[0] & 0x03) << 3) + ((x[1] & 0xE0) >> 5) + '@';
  76  	output[2] = (x[1] & 0x1F) + '@';
  77  	output[3] = 0;
  78  
  79  	if (isupper(output[0]) &&
  80  	    isupper(output[1]) &&
  81  	    isupper(output[2]))
  82  		return 1;
  83  
  84  	memset(output, 0, 4);
  85  	return 0;
  86  }
  87  
  88  static int
  89  detailed_cvt_descriptor(unsigned char *x, int first)
  90  {
  91  	const unsigned char empty[3] = { 0, 0, 0 };
  92  	static const char *names[] = { "50", "60", "75", "85" };
  93  	int width = 0, height = 0;
  94  	int valid = 1;
  95  	int fifty = 0, sixty = 0, seventyfive = 0, eightyfive = 0, reduced = 0;
  96  
  97  	if (!first && !memcmp(x, empty, 3))
  98  		return valid;
  99  
 100  	height = x[0];
 101  	height |= (x[1] & 0xf0) << 4;
 102  	height++;
 103  	height *= 2;
 104  
 105  	switch (x[1] & 0x0c) {
 106  	case 0x00:
 107  		width = (height * 4) / 3; break;
 108  	case 0x04:
 109  		width = (height * 16) / 9; break;
 110  	case 0x08:
 111  		width = (height * 16) / 10; break;
 112  	case 0x0c:
 113  		width = (height * 15) / 9; break;
 114  	}
 115  
 116  	if (x[1] & 0x03)
 117  		valid = 0;
 118  	if (x[2] & 0x80)
 119  		valid = 0;
 120  	if (!(x[2] & 0x1f))
 121  		valid = 0;
 122  
 123  	fifty	= (x[2] & 0x10);
 124  	sixty	= (x[2] & 0x08);
 125  	seventyfive = (x[2] & 0x04);
 126  	eightyfive  = (x[2] & 0x02);
 127  	reduced	= (x[2] & 0x01);
 128  
 129  	if (!valid) {
 130  		printk(BIOS_SPEW, "    (broken)\n");
 131  	} else {
 132  		printk(BIOS_SPEW,
 133  			"    %dx%d @ (%s%s%s%s%s) Hz (%s%s preferred)\n",
 134  		       width, height,
 135  		       fifty ? "50 " : "",
 136  		       sixty ? "60 " : "",
 137  		       seventyfive ? "75 " : "",
 138  		       eightyfive ? "85 " : "",
 139  		       reduced ? "60RB " : "",
 140  		       names[(x[2] & 0x60) >> 5],
 141  		       (((x[2] & 0x60) == 0x20) && reduced) ? "RB" : "");
 142  	}
 143  
 144  	return valid;
 145  }
 146  
 147  /* extract a CP437 string from a detailed subblock, checking for termination (if
 148   * less than len of bytes) with LF and padded with SP.
 149   */
 150  static char *
 151  extract_string(unsigned char *x, int *valid_termination, int len)
 152  {
 153  	static char ret[EDID_ASCII_STRING_LENGTH + 1];
 154  	int i, seen_newline = 0;
 155  
 156  	memset(ret, 0, sizeof(ret));
 157  
 158  	for (i = 0; i < MIN(len, EDID_ASCII_STRING_LENGTH); i++) {
 159  		if (seen_newline) {
 160  			if (x[i] != 0x20) {
 161  				*valid_termination = 0;
 162  				return ret;
 163  			}
 164  		} else if (x[i] == 0x0a) {
 165  			seen_newline = 1;
 166  		} else {
 167  			/* normal characters */
 168  			ret[i] = x[i];
 169  		}
 170  	}
 171  
 172  	return ret;
 173  }
 174  
 175  /* 1 means valid data */
 176  static int
 177  detailed_block(struct edid *result_edid, unsigned char *x, int in_extension,
 178  	       struct edid_context *c)
 179  {
 180  	struct edid *out = &tmp_edid;
 181  	int i;
 182  
 183  	if (console_log_level(BIOS_SPEW)) {
 184  		printk(BIOS_SPEW, "Hex of detail: ");
 185  		for (i = 0; i < 18; i++)
 186  			printk(BIOS_SPEW, "%02x", x[i]);
 187  		printk(BIOS_SPEW, "\n");
 188  	}
 189  
 190  	/* Result might already have some valid fields like mode_is_supported */
 191  	*out = *result_edid;
 192  
 193  	if (x[0] == 0 && x[1] == 0) {
 194  		/* Monitor descriptor block, not detailed timing descriptor. */
 195  		if (x[2] != 0) {
 196  			/* 1.3, 3.10.3 */
 197  			printk(BIOS_SPEW,
 198  				"Monitor descriptor block has byte 2 nonzero (0x%02x)\n",
 199  			       x[2]);
 200  			c->has_valid_descriptor_pad = 0;
 201  		}
 202  		if (x[3] != 0xfd && x[4] != 0x00) {
 203  			/* 1.3, 3.10.3 */
 204  			printk(BIOS_SPEW,
 205  				"Monitor descriptor block has byte 4 nonzero (0x%02x)\n",
 206  			       x[4]);
 207  			c->has_valid_descriptor_pad = 0;
 208  		}
 209  
 210  		c->seen_non_detailed_descriptor = 1;
 211  		if (x[3] <= 0xF) {
 212  			/*
 213  			 * in principle we can decode these, if we know what
 214  			 * they are.
 215  			 * 0x0f seems to be common in laptop panels.
 216  			 * 0x0e is used by EPI: http://www.epi-standard.org/
 217  			 */
 218  			printk(BIOS_SPEW,
 219  				"Manufacturer-specified data, tag %d\n", x[3]);
 220  			return 1;
 221  		}
 222  		switch (x[3]) {
 223  		case 0x10:
 224  			printk(BIOS_SPEW, "Dummy block\n");
 225  			for (i = 5; i < 18; i++)
 226  				if (x[i] != 0x00)
 227  					c->has_valid_dummy_block = 0;
 228  			return 1;
 229  		case 0xF7:
 230  			/* TODO */
 231  			printk(BIOS_SPEW, "Established timings III\n");
 232  			return 1;
 233  		case 0xF8:
 234  		{
 235  			int valid_cvt = 1; /* just this block */
 236  			printk(BIOS_SPEW, "CVT 3-byte code descriptor:\n");
 237  			if (x[5] != 0x01) {
 238  				c->has_valid_cvt = 0;
 239  				return 0;
 240  			}
 241  			for (i = 0; i < 4; i++)
 242  				valid_cvt &= detailed_cvt_descriptor(x + 6
 243  					+ (i * 3), (i == 0));
 244  			c->has_valid_cvt &= valid_cvt;
 245  			return 1;
 246  		}
 247  		case 0xF9:
 248  			/* TODO */
 249  			printk(BIOS_SPEW, "Color management data\n");
 250  			return 1;
 251  		case 0xFA:
 252  			/* TODO */
 253  			printk(BIOS_SPEW, "More standard timings\n");
 254  			return 1;
 255  		case 0xFB:
 256  			/* TODO */
 257  			printk(BIOS_SPEW, "Color point\n");
 258  			return 1;
 259  		case 0xFC:
 260  			printk(BIOS_SPEW, "Monitor name: %s\n",
 261  			       extract_string(x + 5,
 262  					      &c->has_valid_string_termination,
 263  					      EDID_ASCII_STRING_LENGTH));
 264  			c->has_name_descriptor = 1;
 265  			return 1;
 266  		case 0xFD:
 267  		{
 268  			int h_max_offset = 0, h_min_offset = 0;
 269  			int v_max_offset = 0, v_min_offset = 0;
 270  			int is_cvt = 0;
 271  			c->has_range_descriptor = 1;
 272  			extra_info.range_class = "";
 273  			/*
 274  			 * XXX todo: implement feature flags, vtd blocks
 275  			 * XXX check: ranges are well-formed; block termination
 276  			 * if no vtd
 277  			 */
 278  			if (c->claims_one_point_four) {
 279  				if (x[4] & 0x02) {
 280  					v_max_offset = 255;
 281  					if (x[4] & 0x01)
 282  						v_min_offset = 255;
 283  				}
 284  				if (x[4] & 0x04) {
 285  					h_max_offset = 255;
 286  					if (x[4] & 0x03)
 287  						h_min_offset = 255;
 288  				}
 289  			} else if (x[4]) {
 290  				c->has_valid_range_descriptor = 0;
 291  			}
 292  
 293  			/*
 294  			 * despite the values, this is not a bitfield.
 295  			 */
 296  			switch (x[10]) {
 297  			case 0x00: /* default gtf */
 298  				extra_info.range_class = "GTF";
 299  				break;
 300  			case 0x01: /* range limits only */
 301  				extra_info.range_class = "bare limits";
 302  				if (!c->claims_one_point_four)
 303  					c->has_valid_range_descriptor = 0;
 304  				break;
 305  			case 0x02: /* secondary gtf curve */
 306  				extra_info.range_class = "GTF with icing";
 307  				break;
 308  			case 0x04: /* cvt */
 309  				extra_info.range_class = "CVT";
 310  				is_cvt = 1;
 311  				if (!c->claims_one_point_four)
 312  					c->has_valid_range_descriptor = 0;
 313  				break;
 314  			default: /* invalid */
 315  				c->has_valid_range_descriptor = 0;
 316  				extra_info.range_class = "invalid";
 317  				break;
 318  			}
 319  
 320  			if (x[5] + v_min_offset > x[6] + v_max_offset)
 321  				c->has_valid_range_descriptor = 0;
 322  			if (x[7] + h_min_offset > x[8] + h_max_offset)
 323  				c->has_valid_range_descriptor = 0;
 324  			printk(BIOS_SPEW,
 325  				"Monitor ranges (%s): %d-%dHz V, %d-%dkHz H",
 326  			       extra_info.range_class,
 327  			       x[5] + v_min_offset, x[6] + v_max_offset,
 328  			       x[7] + h_min_offset, x[8] + h_max_offset);
 329  			if (x[9])
 330  				printk(BIOS_SPEW,
 331  					", max dotclock %dMHz\n", x[9] * 10);
 332  			else {
 333  				if (c->claims_one_point_four)
 334  					c->has_valid_max_dotclock = 0;
 335  				printk(BIOS_SPEW, "\n");
 336  			}
 337  
 338  			if (is_cvt) {
 339  				int max_h_pixels = 0;
 340  
 341  				printk(BIOS_SPEW, "CVT version %d.%d\n",
 342  					x[11] & 0xf0 >> 4, x[11] & 0x0f);
 343  
 344  				if (x[12] & 0xfc) {
 345  					int raw_offset = (x[12] & 0xfc) >> 2;
 346  					printk(BIOS_SPEW,
 347  						"Real max dotclock: %dKHz\n",
 348  					       (x[9] * 10000)
 349  						- (raw_offset * 250));
 350  					if (raw_offset >= 40)
 351  						c->warning_excessive_dotclock_correction = 1;
 352  				}
 353  
 354  				max_h_pixels = x[12] & 0x03;
 355  				max_h_pixels <<= 8;
 356  				max_h_pixels |= x[13];
 357  				max_h_pixels *= 8;
 358  				if (max_h_pixels)
 359  					printk(BIOS_SPEW,
 360  					     "Max active pixels per line: %d\n",
 361  					     max_h_pixels);
 362  
 363  				printk(BIOS_SPEW,
 364  				    "Supported aspect ratios: %s %s %s %s %s\n",
 365  				     x[14] & 0x80 ? "4:3" : "",
 366  				     x[14] & 0x40 ? "16:9" : "",
 367  				     x[14] & 0x20 ? "16:10" : "",
 368  				     x[14] & 0x10 ? "5:4" : "",
 369  				     x[14] & 0x08 ? "15:9" : "");
 370  				if (x[14] & 0x07)
 371  					c->has_valid_range_descriptor = 0;
 372  
 373  				printk(BIOS_SPEW, "Preferred aspect ratio: ");
 374  				switch ((x[15] & 0xe0) >> 5) {
 375  				case 0x00:
 376  					printk(BIOS_SPEW, "4:3");
 377  					break;
 378  				case 0x01:
 379  					printk(BIOS_SPEW, "16:9");
 380  					break;
 381  				case 0x02:
 382  					printk(BIOS_SPEW, "16:10");
 383  					break;
 384  				case 0x03:
 385  					printk(BIOS_SPEW, "5:4");
 386  					break;
 387  				case 0x04:
 388  					printk(BIOS_SPEW, "15:9");
 389  					break;
 390  				default:
 391  					printk(BIOS_SPEW, "(broken)");
 392  					break;
 393  				}
 394  				printk(BIOS_SPEW, "\n");
 395  
 396  				if (x[15] & 0x04)
 397  					printk(BIOS_SPEW,
 398  					    "Supports CVT standard blanking\n");
 399  				if (x[15] & 0x10)
 400  					printk(BIOS_SPEW,
 401  					    "Supports CVT reduced blanking\n");
 402  
 403  				if (x[15] & 0x07)
 404  					c->has_valid_range_descriptor = 0;
 405  
 406  				if (x[16] & 0xf0) {
 407  					printk(BIOS_SPEW,
 408  						"Supported display scaling:\n");
 409  					if (x[16] & 0x80)
 410  						printk(BIOS_SPEW,
 411  						    "    Horizontal shrink\n");
 412  					if (x[16] & 0x40)
 413  						printk(BIOS_SPEW,
 414  						    "    Horizontal stretch\n");
 415  					if (x[16] & 0x20)
 416  						printk(BIOS_SPEW,
 417  						    "    Vertical shrink\n");
 418  					if (x[16] & 0x10)
 419  						printk(BIOS_SPEW,
 420  						    "    Vertical stretch\n");
 421  				}
 422  
 423  				if (x[16] & 0x0f)
 424  					c->has_valid_range_descriptor = 0;
 425  
 426  				if (x[17])
 427  					printk(BIOS_SPEW,
 428  					  "Preferred vertical refresh: %d Hz\n",
 429  					  x[17]);
 430  				else
 431  					c->warning_zero_preferred_refresh = 1;
 432  			}
 433  
 434  			/*
 435  			 * Slightly weird to return a global, but I've never
 436  			 * seen any EDID block with two range descriptors, so
 437  			 * it's harmless.
 438  			 */
 439  			return 1;
 440  		}
 441  		case 0xFE:
 442  			/*
 443  			 * TODO: Two of these in a row, in the third and fourth
 444  			 * slots, seems to be specified by SPWG:
 445  			 * http://www.spwg.org/
 446  			 */
 447  			strcpy(result_edid->ascii_string, extract_string(x + 5,
 448  				&c->has_valid_string_termination,
 449  						EDID_ASCII_STRING_LENGTH));
 450  			printk(BIOS_SPEW, "ASCII string: %s\n",
 451  				result_edid->ascii_string);
 452  			return 1;
 453  		case 0xFF:
 454  			printk(BIOS_SPEW, "Serial number: %s\n",
 455  			       extract_string(x + 5,
 456  			       &c->has_valid_string_termination,
 457  			       EDID_ASCII_STRING_LENGTH));
 458  			return 1;
 459  		default:
 460  			printk(BIOS_SPEW,
 461  				"Unknown monitor description type %d\n",
 462  				x[3]);
 463  			return 0;
 464  		}
 465  	}
 466  
 467  	if (c->seen_non_detailed_descriptor && !in_extension)
 468  		c->has_valid_descriptor_ordering = 0;
 469  
 470  	/* Edid contains pixel clock in terms of 10KHz */
 471  	out->mode.pixel_clock = (x[0] + (x[1] << 8)) * 10;
 472  	/*
 473  	  LVDS supports following pixel clocks
 474  	  25000...112000 kHz: single channel
 475  	  80000...224000 kHz: dual channel
 476  	  There is some overlap in theoretically supported
 477  	  pixel clock between single-channel and dual-channel.
 478  	  In practice with current panels all panels
 479  	  <= 75200 kHz: single channel
 480  	  >= 97750 kHz: dual channel
 481  	  We have no samples between those values, so put a
 482  	  threshold at 95000 kHz. If we get anything over
 483  	  95000 kHz with single channel, we can make this
 484  	  more sophisticated but it's currently not needed.
 485  	 */
 486  	out->mode.lvds_dual_channel = (out->mode.pixel_clock >= 95000);
 487  	extra_info.x_mm = (x[12] + ((x[14] & 0xF0) << 4));
 488  	extra_info.y_mm = (x[13] + ((x[14] & 0x0F) << 8));
 489  	out->mode.ha = (x[2] + ((x[4] & 0xF0) << 4));
 490  	out->mode.hbl = (x[3] + ((x[4] & 0x0F) << 8));
 491  	out->mode.hso = (x[8] + ((x[11] & 0xC0) << 2));
 492  	out->mode.hspw = (x[9] + ((x[11] & 0x30) << 4));
 493  	out->mode.hborder = x[15];
 494  	out->mode.va = (x[5] + ((x[7] & 0xF0) << 4));
 495  	out->mode.vbl = (x[6] + ((x[7] & 0x0F) << 8));
 496  	out->mode.vso = ((x[10] >> 4) + ((x[11] & 0x0C) << 2));
 497  	out->mode.vspw = ((x[10] & 0x0F) + ((x[11] & 0x03) << 4));
 498  	out->mode.vborder = x[16];
 499  
 500  	/* We assume rgb888 (32 bits per pixel) framebuffers by default.
 501  	 * Chipsets that want something else will need to override this with
 502  	 * another call to edid_set_framebuffer_bits_per_pixel(). As a cheap
 503  	 * heuristic, assume that X86 systems require a 64-byte row alignment
 504  	 * (since that seems to be true for most Intel chipsets). */
 505  	if (ENV_X86)
 506  		edid_set_framebuffer_bits_per_pixel(out, 32, 64);
 507  	else
 508  		edid_set_framebuffer_bits_per_pixel(out, 32, 0);
 509  
 510  	switch ((x[17] & 0x18) >> 3) {
 511  	case 0x00:
 512  		extra_info.syncmethod = " analog composite";
 513  		break;
 514  	case 0x01:
 515  		extra_info.syncmethod = " bipolar analog composite";
 516  		break;
 517  	case 0x02:
 518  		extra_info.syncmethod = " digital composite";
 519  		break;
 520  	case 0x03:
 521  		extra_info.syncmethod = "";
 522  		break;
 523  	}
 524  	out->mode.pvsync = (x[17] & (1 << 2)) ? '+' : '-';
 525  	out->mode.phsync = (x[17] & (1 << 1)) ? '+' : '-';
 526  	switch (x[17] & 0x61) {
 527  	case 0x20:
 528  		extra_info.stereo = "field sequential L/R";
 529  		break;
 530  	case 0x40:
 531  		extra_info.stereo = "field sequential R/L";
 532  		break;
 533  	case 0x21:
 534  		extra_info.stereo = "interleaved right even";
 535  		break;
 536  	case 0x41:
 537  		extra_info.stereo = "interleaved left even";
 538  		break;
 539  	case 0x60:
 540  		extra_info.stereo = "four way interleaved";
 541  		break;
 542  	case 0x61:
 543  		extra_info.stereo = "side by side interleaved";
 544  		break;
 545  	default:
 546  		extra_info.stereo = "";
 547  		break;
 548  	}
 549  
 550  	printk(BIOS_SPEW,
 551  		"Detailed mode (IN HEX): Clock %d KHz, %x mm x %x mm\n"
 552  	       "               %04x %04x %04x %04x hborder %x\n"
 553  	       "               %04x %04x %04x %04x vborder %x\n"
 554  	       "               %chsync %cvsync%s%s%s\n",
 555  	       out->mode.pixel_clock,
 556  	       extra_info.x_mm,
 557  	       extra_info.y_mm,
 558  	       out->mode.ha, out->mode.ha + out->mode.hso,
 559  	       out->mode.ha + out->mode.hso + out->mode.hspw,
 560  	       out->mode.ha + out->mode.hbl, out->mode.hborder,
 561  	       out->mode.va, out->mode.va + out->mode.vso,
 562  	       out->mode.va + out->mode.vso + out->mode.vspw,
 563  	       out->mode.va + out->mode.vbl, out->mode.vborder,
 564  	       out->mode.phsync, out->mode.pvsync,
 565  	       extra_info.syncmethod, x[17] & 0x80 ? " interlaced" : "",
 566  	       extra_info.stereo);
 567  
 568  	if (!c->did_detailed_timing) {
 569  		printk(BIOS_SPEW, "Did detailed timing\n");
 570  		c->did_detailed_timing = 1;
 571  		*result_edid = *out;
 572  	}
 573  
 574  	return 1;
 575  }
 576  
 577  static int
 578  do_checksum(unsigned char *x)
 579  {
 580  	int valid = 0;
 581  	printk(BIOS_SPEW, "Checksum: 0x%hhx", x[0x7f]);
 582  	{
 583  		unsigned char sum = 0;
 584  		int i;
 585  		for (i = 0; i < 128; i++)
 586  			sum += x[i];
 587  		if (sum) {
 588  			printk(BIOS_SPEW, " (should be 0x%hhx)",
 589  				(unsigned char)(x[0x7f] - sum));
 590  		} else {
 591  			valid = 1;
 592  			printk(BIOS_SPEW, " (valid)");
 593  		}
 594  	}
 595  	printk(BIOS_SPEW, "\n");
 596  	return valid;
 597  }
 598  
 599  /* CEA extension */
 600  
 601  static const char *
 602  audio_format(unsigned char x)
 603  {
 604  	switch (x) {
 605  	case 0: return "RESERVED";
 606  	case 1: return "Linear PCM";
 607  	case 2: return "AC-3";
 608  	case 3: return "MPEG 1 (Layers 1 & 2)";
 609  	case 4: return "MPEG 1 Layer 3 (MP3)";
 610  	case 5: return "MPEG2 (multichannel)";
 611  	case 6: return "AAC";
 612  	case 7: return "DTS";
 613  	case 8: return "ATRAC";
 614  	case 9: return "One Bit Audio";
 615  	case 10: return "Dolby Digital+";
 616  	case 11: return "DTS-HD";
 617  	case 12: return "MAT (MLP)";
 618  	case 13: return "DST";
 619  	case 14: return "WMA Pro";
 620  	case 15: return "RESERVED";
 621  	}
 622  	return "BROKEN"; /* can't happen */
 623  }
 624  
 625  static void
 626  cea_audio_block(unsigned char *x)
 627  {
 628  	int i, format;
 629  	int length = x[0] & 0x1f;
 630  
 631  	if (length % 3) {
 632  		printk(BIOS_SPEW, "Broken CEA audio block length %d\n", length);
 633  		/* XXX non-conformant */
 634  		return;
 635  	}
 636  
 637  	for (i = 1; i < length; i += 3) {
 638  		format = (x[i] & 0x78) >> 3;
 639  		printk(BIOS_SPEW, "    %s, max channels %d\n",
 640  			audio_format(format), x[i] & 0x07);
 641  		printk(BIOS_SPEW,
 642  			"    Supported sample rates (kHz):%s%s%s%s%s%s%s\n",
 643  		       (x[i+1] & 0x40) ? " 192" : "",
 644  		       (x[i+1] & 0x20) ? " 176.4" : "",
 645  		       (x[i+1] & 0x10) ? " 96" : "",
 646  		       (x[i+1] & 0x08) ? " 88.2" : "",
 647  		       (x[i+1] & 0x04) ? " 48" : "",
 648  		       (x[i+1] & 0x02) ? " 44.1" : "",
 649  		       (x[i+1] & 0x01) ? " 32" : "");
 650  		if (format == 1) {
 651  			printk(BIOS_SPEW,
 652  				"    Supported sample sizes (bits):%s%s%s\n",
 653  			       (x[2] & 0x04) ? " 24" : "",
 654  			       (x[2] & 0x02) ? " 20" : "",
 655  			       (x[2] & 0x01) ? " 16" : "");
 656  		} else if (format <= 8) {
 657  			printk(BIOS_SPEW,
 658  				"    Maximum bit rate: %d kHz\n", x[2] * 8);
 659  		}
 660  	}
 661  }
 662  
 663  static void
 664  cea_video_block(unsigned char *x)
 665  {
 666  	int i;
 667  	int length = x[0] & 0x1f;
 668  
 669  	for (i = 1; i < length; i++)
 670  		printk(BIOS_SPEW, "    VIC %02d %s\n", x[i] & 0x7f,
 671  		       x[i] & 0x80 ? "(native)" : "");
 672  }
 673  
 674  static void
 675  cea_hdmi_block(struct edid *out, unsigned char *x)
 676  {
 677  	int length = x[0] & 0x1f;
 678  
 679  	out->hdmi_monitor_detected = 1;
 680  
 681  	printk(BIOS_SPEW, " (HDMI)\n");
 682  	printk(BIOS_SPEW,
 683  	       "    Source physical address %d.%d.%d.%d\n",
 684  	       x[4] >> 4, x[4] & 0x0f, x[5] >> 4, x[5] & 0x0f);
 685  
 686  	if (length > 5) {
 687  		if (x[6] & 0x80)
 688  			printk(BIOS_SPEW, "    Supports_AI\n");
 689  		if (x[6] & 0x40)
 690  			printk(BIOS_SPEW, "    DC_48bit\n");
 691  		if (x[6] & 0x20)
 692  			printk(BIOS_SPEW, "    DC_36bit\n");
 693  		if (x[6] & 0x10)
 694  			printk(BIOS_SPEW, "    DC_30bit\n");
 695  		if (x[6] & 0x08)
 696  			printk(BIOS_SPEW, "    DC_Y444\n");
 697  		/* two reserved */
 698  		if (x[6] & 0x01)
 699  			printk(BIOS_SPEW, "    DVI_Dual\n");
 700  	}
 701  
 702  	if (length > 6)
 703  		printk(BIOS_SPEW, "    Maximum TMDS clock: %dMHz\n", x[7] * 5);
 704  
 705  	/* XXX the walk here is really ugly, and needs to be length-checked */
 706  	if (length > 7) {
 707  		int b = 0;
 708  
 709  		if (x[8] & 0x80) {
 710  			printk(BIOS_SPEW, "    Video latency: %d\n", x[9 + b]);
 711  			printk(BIOS_SPEW, "    Audio latency: %d\n", x[10 + b]);
 712  			b += 2;
 713  		}
 714  
 715  		if (x[8] & 0x40) {
 716  			printk(BIOS_SPEW,
 717  				"    Interlaced video latency: %d\n", x[9 + b]);
 718  			printk(BIOS_SPEW,
 719  				"    Interlaced audio latency: %d\n",
 720  				x[10 + b]);
 721  			b += 2;
 722  		}
 723  
 724  		if (x[8] & 0x20) {
 725  			int mask = 0, formats = 0;
 726  			int len_xx, len_3d;
 727  			printk(BIOS_SPEW, "    Extended HDMI video details:\n");
 728  			if (x[9 + b] & 0x80)
 729  				printk(BIOS_SPEW, "      3D present\n");
 730  			if ((x[9 + b] & 0x60) == 0x20) {
 731  				printk(BIOS_SPEW,
 732  				  "      All advertised VICs are 3D-capable\n");
 733  				formats = 1;
 734  			}
 735  			if ((x[9 + b] & 0x60) == 0x40) {
 736  				printk(BIOS_SPEW,
 737  					"      3D-capable-VIC mask present\n");
 738  				formats = 1;
 739  				mask = 1;
 740  			}
 741  			switch (x[9 + b] & 0x18) {
 742  			case 0x00:
 743  				break;
 744  			case 0x08:
 745  				printk(BIOS_SPEW, "      Base EDID image size is aspect ratio\n");
 746  				break;
 747  			case 0x10:
 748  				printk(BIOS_SPEW, "      Base EDID image size is in units of 1cm\n");
 749  				break;
 750  			case 0x18:
 751  				printk(BIOS_SPEW, "      Base EDID image size is in units of 5cm\n");
 752  				break;
 753  			}
 754  			len_xx = (x[10 + b] & 0xe0) >> 5;
 755  			len_3d = (x[10 + b] & 0x1f) >> 0;
 756  			b += 2;
 757  
 758  			if (len_xx) {
 759  				printk(BIOS_SPEW, "      Skipping %d bytes that HDMI refuses to publicly"
 760  				       " document\n", len_xx);
 761  				b += len_xx;
 762  			}
 763  
 764  			if (len_3d) {
 765  				if (formats) {
 766  					if (x[9 + b] & 0x01)
 767  						printk(BIOS_SPEW, "      Side-by-side 3D supported\n");
 768  					if (x[10 + b] & 0x40)
 769  						printk(BIOS_SPEW, "      Top-and-bottom 3D supported\n");
 770  					if (x[10 + b] & 0x01)
 771  						printk(BIOS_SPEW, "      Frame-packing 3D supported\n");
 772  					b += 2;
 773  				}
 774  				if (mask) {
 775  					int i;
 776  					printk(BIOS_SPEW,
 777  						"      3D VIC indices:");
 778  					/* worst bit ordering ever */
 779  					for (i = 0; i < 8; i++)
 780  						if (x[10 + b] & (1 << i))
 781  							printk(BIOS_SPEW,
 782  								" %d", i);
 783  					for (i = 0; i < 8; i++)
 784  						if (x[9 + b] & (1 << i))
 785  							printk(BIOS_SPEW,
 786  								" %d", i + 8);
 787  					printk(BIOS_SPEW, "\n");
 788  					b += 2;
 789  				}
 790  
 791  				/*
 792  				 * XXX list of nibbles:
 793  				 * 2D_VIC_Order_X
 794  				 * 3D_Structure_X
 795  				 * (optionally: 3D_Detail_X and reserved)
 796  				 */
 797  			}
 798  		}
 799  		/* Tell static analysis we know index b is left unused. */
 800  		(void)b;
 801  	}
 802  }
 803  
 804  static void
 805  cea_block(struct edid *out, unsigned char *x)
 806  {
 807  	unsigned int oui;
 808  
 809  	switch ((x[0] & 0xe0) >> 5) {
 810  	case 0x01:
 811  		printk(BIOS_SPEW, "  Audio data block\n");
 812  		cea_audio_block(x);
 813  		break;
 814  	case 0x02:
 815  		printk(BIOS_SPEW, "  Video data block\n");
 816  		cea_video_block(x);
 817  		break;
 818  	case 0x03:
 819  		/* yes really, endianness lols */
 820  		oui = (x[3] << 16) + (x[2] << 8) + x[1];
 821  		printk(BIOS_SPEW, "  Vendor-specific data block, OUI %06x",
 822  			oui);
 823  		if (oui == 0x000c03)
 824  			cea_hdmi_block(out, x);
 825  		else
 826  			printk(BIOS_SPEW, "\n");
 827  		break;
 828  	case 0x04:
 829  		printk(BIOS_SPEW, "  Speaker allocation data block\n");
 830  		break;
 831  	case 0x05:
 832  		printk(BIOS_SPEW, "  VESA DTC data block\n");
 833  		break;
 834  	case 0x07:
 835  		printk(BIOS_SPEW, "  Extended tag: ");
 836  		switch (x[1]) {
 837  		case 0x00:
 838  			printk(BIOS_SPEW, "video capability data block\n");
 839  			break;
 840  		case 0x01:
 841  			printk(BIOS_SPEW, "vendor-specific video data block\n");
 842  			break;
 843  		case 0x02:
 844  			printk(BIOS_SPEW,
 845  			  "VESA video display device information data block\n");
 846  			break;
 847  		case 0x03:
 848  			printk(BIOS_SPEW, "VESA video data block\n");
 849  			break;
 850  		case 0x04:
 851  			printk(BIOS_SPEW, "HDMI video data block\n");
 852  			break;
 853  		case 0x05:
 854  			printk(BIOS_SPEW, "Colorimetry data block\n");
 855  			break;
 856  		case 0x10:
 857  			printk(BIOS_SPEW, "CEA miscellaneous audio fields\n");
 858  			break;
 859  		case 0x11:
 860  			printk(BIOS_SPEW, "Vendor-specific audio data block\n");
 861  			break;
 862  		case 0x12:
 863  			printk(BIOS_SPEW, "HDMI audio data block\n");
 864  			break;
 865  		default:
 866  			if (x[1] >= 6 && x[1] <= 15)
 867  				printk(BIOS_SPEW,
 868  					"Reserved video block (%02x)\n", x[1]);
 869  			else if (x[1] >= 19 && x[1] <= 31)
 870  				printk(BIOS_SPEW,
 871  					"Reserved audio block (%02x)\n", x[1]);
 872  			else
 873  				printk(BIOS_SPEW, "Unknown (%02x)\n", x[1]);
 874  			break;
 875  		}
 876  		break;
 877  	default:
 878  	{
 879  		int tag = (*x & 0xe0) >> 5;
 880  		int length = *x & 0x1f;
 881  		printk(BIOS_SPEW,
 882  			"  Unknown tag %d, length %d (raw %02x)\n",
 883  			tag, length, *x);
 884  		break;
 885  	}
 886  	}
 887  }
 888  
 889  static int
 890  parse_cea(struct edid *out, unsigned char *x, struct edid_context *c)
 891  {
 892  	int ret = 0;
 893  	int version = x[1];
 894  	int offset = x[2];
 895  	unsigned char *detailed;
 896  
 897  	if (version >= 1)
 898  		do {
 899  			if (version == 1 && x[3] != 0)
 900  				ret = 1;
 901  
 902  			if (offset < 4)
 903  				break;
 904  
 905  			if (version < 3)
 906  				printk(BIOS_SPEW,
 907  					"%d 8-byte timing descriptors\n",
 908  					(offset - 4) / 8);
 909  			else if (version == 3) {
 910  				int i;
 911  				printk(BIOS_SPEW,
 912  					"%d bytes of CEA data\n", offset - 4);
 913  				for (i = 4; i < offset; i += (x[i] & 0x1f) + 1)
 914  					cea_block(out, x + i);
 915  			}
 916  
 917  			if (version >= 2) {
 918  				if (x[3] & 0x80)
 919  					printk(BIOS_SPEW,
 920  					  "Underscans PC formats by default\n");
 921  				if (x[3] & 0x40)
 922  					printk(BIOS_SPEW,
 923  						"Basic audio support\n");
 924  				if (x[3] & 0x20)
 925  					printk(BIOS_SPEW,
 926  						"Supports YCbCr 4:4:4\n");
 927  				if (x[3] & 0x10)
 928  					printk(BIOS_SPEW,
 929  						"Supports YCbCr 4:2:2\n");
 930  				printk(BIOS_SPEW,
 931  					"%d native detailed modes\n",
 932  					x[3] & 0x0f);
 933  			}
 934  
 935  			for (detailed = x + offset; detailed + 18 < x + 127;
 936  				detailed += 18)
 937  				if (detailed[0])
 938  					detailed_block(out, detailed, 1, c);
 939  		} while (0);
 940  
 941  	c->has_valid_checksum &= do_checksum(x);
 942  	return ret;
 943  }
 944  
 945  /* generic extension code */
 946  
 947  static void
 948  extension_version(struct edid *out, unsigned char *x)
 949  {
 950  	printk(BIOS_SPEW, "Extension version: %d\n", x[1]);
 951  }
 952  
 953  static int
 954  parse_extension(struct edid *out, unsigned char *x, struct edid_context *c)
 955  {
 956  	int conformant_extension = 0;
 957  	printk(BIOS_SPEW, "\n");
 958  
 959  	switch (x[0]) {
 960  	case 0x02:
 961  		printk(BIOS_SPEW, "CEA extension block\n");
 962  		extension_version(out, x);
 963  		conformant_extension = parse_cea(out, x, c);
 964  		break;
 965  	case 0x10:
 966  		printk(BIOS_SPEW, "VTB extension block\n");
 967  		break;
 968  	case 0x40:
 969  		printk(BIOS_SPEW, "DI extension block\n");
 970  		break;
 971  	case 0x50:
 972  		printk(BIOS_SPEW, "LS extension block\n");
 973  		break;
 974  	case 0x60:
 975  		printk(BIOS_SPEW, "DPVL extension block\n");
 976  		break;
 977  	case 0xF0:
 978  		printk(BIOS_SPEW, "Block map\n");
 979  		break;
 980  	case 0xFF:
 981  		printk(BIOS_SPEW, "Manufacturer-specific extension block\n");
 982  		break;
 983  	default:
 984  		printk(BIOS_SPEW, "Unknown extension block\n");
 985  		break;
 986  	}
 987  
 988  	printk(BIOS_SPEW, "\n");
 989  
 990  	return conformant_extension;
 991  }
 992  
 993  static const struct {
 994  	int x, y, refresh;
 995  } established_timings[] = {
 996  	/* 0x23 bit 7 - 0 */
 997  	{720, 400, 70},
 998  	{720, 400, 88},
 999  	{640, 480, 60},
1000  	{640, 480, 67},
1001  	{640, 480, 72},
1002  	{640, 480, 75},
1003  	{800, 600, 56},
1004  	{800, 600, 60},
1005  	/* 0x24 bit 7 - 0 */
1006  	{800, 600, 72},
1007  	{800, 600, 75},
1008  	{832, 624, 75},
1009  	{1280, 768, 87},
1010  	{1024, 768, 60},
1011  	{1024, 768, 70},
1012  	{1024, 768, 75},
1013  	{1280, 1024, 75},
1014  	/* 0x25 bit 7*/
1015  	{1152, 870, 75},
1016  };
1017  
1018  static void print_subsection(const char *name, unsigned char *edid, int start,
1019  			     int end)
1020  {
1021  	int i;
1022  
1023  	printk(BIOS_SPEW, "%s:", name);
1024  	for (i = strlen(name); i < 15; i++)
1025  		printk(BIOS_SPEW, " ");
1026  	for (i = start; i <= end; i++)
1027  		printk(BIOS_SPEW, " %02x", edid[i]);
1028  	printk(BIOS_SPEW, "\n");
1029  }
1030  
1031  static void dump_breakdown(unsigned char *edid)
1032  {
1033  	printk(BIOS_SPEW, "Extracted contents:\n");
1034  	print_subsection("header", edid, 0, 7);
1035  	print_subsection("serial number", edid, 8, 17);
1036  	print_subsection("version", edid, 18, 19);
1037  	print_subsection("basic params", edid, 20, 24);
1038  	print_subsection("chroma info", edid, 25, 34);
1039  	print_subsection("established", edid, 35, 37);
1040  	print_subsection("standard", edid, 38, 53);
1041  	print_subsection("descriptor 1", edid, 54, 71);
1042  	print_subsection("descriptor 2", edid, 72, 89);
1043  	print_subsection("descriptor 3", edid, 90, 107);
1044  	print_subsection("descriptor 4", edid, 108, 125);
1045  	print_subsection("extensions", edid, 126, 126);
1046  	print_subsection("checksum", edid, 127, 127);
1047  	printk(BIOS_SPEW, "\n");
1048  }
1049  
1050  /*
1051   * Lookup table of some well-known modes that can be useful in case the
1052   * auto-detected mode is unsuitable.
1053   * ha = hdisplay;			va = vdisplay;
1054   * hbl = htotal - hdisplay;		vbl = vtotal - vdisplay;
1055   * hso = hsync_start - hdsiplay;	vso = vsync_start - vdisplay;
1056   * hspw = hsync_end - hsync_start;	vspw = vsync_end - vsync_start;
1057   */
1058  static struct edid_mode known_modes[NUM_KNOWN_MODES] = {
1059  	[EDID_MODE_640x480_60Hz] = {
1060  		.name = "640x480@60Hz", .pixel_clock = 25200, .refresh = 60,
1061  		.ha = 640, .hbl = 160, .hso = 16, .hspw = 96,
1062  		.va = 480, .vbl = 45, .vso = 10, .vspw = 2,
1063  		.phsync = '-', .pvsync = '-' },
1064  	[EDID_MODE_720x480_60Hz] = {
1065  		.name = "720x480@60Hz", .pixel_clock = 27000, .refresh = 60,
1066  		.ha = 720, .hbl = 138, .hso = 16, .hspw = 62,
1067  		.va = 480, .vbl = 45, .vso = 9, .vspw = 6,
1068  		.phsync = '-', .pvsync = '-' },
1069  	[EDID_MODE_1280x720_60Hz] = {
1070  		.name = "1280x720@60Hz", .pixel_clock = 74250, .refresh = 60,
1071  		.ha = 1280, .hbl = 370, .hso = 110, .hspw = 40,
1072  		.va = 720, .vbl = 30, .vso = 5, .vspw = 20,
1073  		.phsync = '+', .pvsync = '+' },
1074  	[EDID_MODE_1920x1080_60Hz] = {
1075  		.name = "1920x1080@60Hz", .pixel_clock = 148500, .refresh = 60,
1076  		.ha = 1920, .hbl = 280, .hso = 88, .hspw = 44,
1077  		.va = 1080, .vbl = 45, .vso = 4, .vspw = 5,
1078  		.phsync = '+', .pvsync = '+' },
1079  };
1080  
1081  int set_display_mode(struct edid *edid, enum edid_modes mode)
1082  {
1083  	if (mode == EDID_MODE_AUTO)
1084  		return 0;
1085  
1086  	if (edid->mode_is_supported[mode]) {
1087  		printk(BIOS_DEBUG, "Forcing mode %s\n", known_modes[mode].name);
1088  		edid->mode = known_modes[mode];
1089  		return 0;
1090  	}
1091  
1092  	printk(BIOS_ERR, "Requested display mode not supported.\n");
1093  	return -1;
1094  }
1095  
1096  /*
1097   * Given a raw edid block, decode it into a form
1098   * that other parts of coreboot can use -- mainly
1099   * graphics bringup functions. The raw block is
1100   * required to be 128 bytes long, per the standard,
1101   * but we have no way of checking this minimum length.
1102   * We accept what we are given.
1103   */
1104  int decode_edid(unsigned char *edid, int size, struct edid *out)
1105  {
1106  	int analog, i, j;
1107  	struct edid_context c = {
1108  	    .has_valid_cvt = 1,
1109  	    .has_valid_dummy_block = 1,
1110  	    .has_valid_descriptor_ordering = 1,
1111  	    .has_valid_detailed_blocks = 1,
1112  	    .has_valid_descriptor_pad = 1,
1113  	    .has_valid_range_descriptor = 1,
1114  	    .has_valid_max_dotclock = 1,
1115  	    .has_valid_string_termination = 1,
1116  	    .conformant = EDID_CONFORMANT,
1117  	};
1118  
1119  	if (!edid) {
1120  		printk(BIOS_ERR, "No EDID found\n");
1121  		return EDID_ABSENT;
1122  	}
1123  
1124  	dump_breakdown(edid);
1125  
1126  	if (memcmp(edid, "\x00\xFF\xFF\xFF\xFF\xFF\xFF\x00", 8)) {
1127  		printk(BIOS_ERR, "No header found\n");
1128  		return EDID_ABSENT;
1129  	}
1130  
1131  	memset(out, 0, sizeof(*out));
1132  
1133  	if (manufacturer_name(edid + 0x08, out->manufacturer_name))
1134  		c.manufacturer_name_well_formed = 1;
1135  
1136  	extra_info.model = (unsigned short)(edid[0x0A] + (edid[0x0B] << 8));
1137  	extra_info.serial = (unsigned int)(edid[0x0C] + (edid[0x0D] << 8)
1138  				     + (edid[0x0E] << 16) + (edid[0x0F] << 24));
1139  
1140  	printk(BIOS_SPEW, "Manufacturer: %s Model %x Serial Number %u\n",
1141  	       out->manufacturer_name,
1142  	       (unsigned short)(edid[0x0A] + (edid[0x0B] << 8)),
1143  	       (unsigned int)(edid[0x0C] + (edid[0x0D] << 8)
1144  			      + (edid[0x0E] << 16) + (edid[0x0F] << 24)));
1145  	/* XXX need manufacturer ID table */
1146  
1147  	if (edid[0x10] < 55 || edid[0x10] == 0xff) {
1148  		c.has_valid_week = 1;
1149  		if (edid[0x11] > 0x0f) {
1150  			if (edid[0x10] == 0xff) {
1151  				c.has_valid_year = 1;
1152  				printk(BIOS_SPEW,
1153  					"Made week %hhd of model year %hhd\n",
1154  					edid[0x10], edid[0x11]);
1155  				extra_info.week = edid[0x10];
1156  				extra_info.year = edid[0x11];
1157  			} else {
1158  				/* we know it's at least 2013, when this code
1159  				 * was written
1160  				 */
1161  				if (edid[0x11] + 90 <= 2013) {
1162  					c.has_valid_year = 1;
1163  					printk(BIOS_SPEW,
1164  						"Made week %hhd of %d\n",
1165  					       edid[0x10], edid[0x11] + 1990);
1166  					extra_info.week = edid[0x10];
1167  					extra_info.year = edid[0x11] + 1990;
1168  				}
1169  			}
1170  		}
1171  	}
1172  
1173  	printk(BIOS_SPEW, "EDID version: %hhd.%hhd\n", edid[0x12], edid[0x13]);
1174  	extra_info.version[0] = edid[0x12];
1175  	extra_info.version[1] = edid[0x13];
1176  
1177  	if (edid[0x12] == 1) {
1178  		if (edid[0x13] > 4) {
1179  			printk(BIOS_SPEW,
1180  				"Claims > 1.4, assuming 1.4 conformance\n");
1181  			edid[0x13] = 4;
1182  		}
1183  		switch (edid[0x13]) {
1184  		case 4:
1185  			c.claims_one_point_four = 1;
1186  			__fallthrough;
1187  		case 3:
1188  			c.claims_one_point_three = 1;
1189  			__fallthrough;
1190  		case 2:
1191  			c.claims_one_point_two = 1;
1192  			__fallthrough;
1193  		default:
1194  			c.claims_one_point_oh = 1;
1195  		}
1196  	}
1197  
1198  	/* display section */
1199  	if (edid[0x14] & 0x80) {
1200  		int conformance_mask;
1201  		analog = 0;
1202  		printk(BIOS_SPEW, "Digital display\n");
1203  		if (c.claims_one_point_four) {
1204  			conformance_mask = 0;
1205  			if ((edid[0x14] & 0x70) == 0x00)
1206  				printk(BIOS_SPEW, "Color depth is undefined\n");
1207  			else if ((edid[0x14] & 0x70) == 0x70)
1208  				c.nonconformant_digital_display = 1;
1209  			else
1210  				printk(BIOS_SPEW,
1211  					"%d bits per primary color channel\n",
1212  				       ((edid[0x14] & 0x70) >> 3) + 4);
1213  			out->panel_bits_per_color = ((edid[0x14] & 0x70) >> 3)
1214  				+ 4;
1215  			out->panel_bits_per_pixel = 3*out->panel_bits_per_color;
1216  
1217  			switch (edid[0x14] & 0x0f) {
1218  			case 0x00:
1219  				printk(BIOS_SPEW,
1220  					"Digital interface is not defined\n");
1221  				break;
1222  			case 0x01:
1223  				printk(BIOS_SPEW, "DVI interface\n");
1224  				break;
1225  			case 0x02:
1226  				printk(BIOS_SPEW, "HDMI-a interface\n");
1227  				break;
1228  			case 0x03:
1229  				printk(BIOS_SPEW, "HDMI-b interface\n");
1230  				break;
1231  			case 0x04:
1232  				printk(BIOS_SPEW, "MDDI interface\n");
1233  				break;
1234  			case 0x05:
1235  				printk(BIOS_SPEW, "DisplayPort interface\n");
1236  				break;
1237  			default:
1238  				c.nonconformant_digital_display = 1;
1239  				break;
1240  			}
1241  			extra_info.type = edid[0x14] & 0x0f;
1242  		} else if (c.claims_one_point_two) {
1243  			conformance_mask = 0x7E;
1244  			if (edid[0x14] & 0x01)
1245  				printk(BIOS_SPEW, "DFP 1.x compatible TMDS\n");
1246  		} else
1247  			conformance_mask = 0x7F;
1248  
1249  		if (!c.nonconformant_digital_display)
1250  			c.nonconformant_digital_display = edid[0x14]
1251  				& conformance_mask;
1252  		extra_info.nonconformant = c.nonconformant_digital_display;
1253  	} else {
1254  		analog = 1;
1255  		int voltage = (edid[0x14] & 0x60) >> 5;
1256  		int sync = (edid[0x14] & 0x0F);
1257  		extra_info.voltage = voltage;
1258  		extra_info.sync = sync;
1259  
1260  		printk(BIOS_SPEW, "Analog display, Input voltage level: %s V\n",
1261  		       voltage == 3 ? "0.7/0.7" :
1262  		       voltage == 2 ? "1.0/0.4" :
1263  		       voltage == 1 ? "0.714/0.286" :
1264  		       "0.7/0.3");
1265  
1266  		if (c.claims_one_point_four) {
1267  			if (edid[0x14] & 0x10)
1268  				printk(BIOS_SPEW,
1269  					"Blank-to-black setup/pedestal\n");
1270  			else
1271  				printk(BIOS_SPEW,
1272  					"Blank level equals black level\n");
1273  		} else if (edid[0x14] & 0x10) {
1274  			/*
1275  			 * XXX this is just the X text.  1.3 says "if set,
1276  			 * display expects a blank-to-black setup or pedestal
1277  			 * per appropriate Signal Level Standard".  Whatever
1278  			 * _that_ means.
1279  			 */
1280  			printk(BIOS_SPEW, "Configurable signal levels\n");
1281  		}
1282  
1283  		printk(BIOS_SPEW, "Sync: %s%s%s%s\n",
1284  			sync & 0x08 ? "Separate " : "",
1285  			sync & 0x04 ? "Composite " : "",
1286  			sync & 0x02 ? "SyncOnGreen " : "",
1287  			sync & 0x01 ? "Serration " : "");
1288  	}
1289  
1290  
1291  	if (edid[0x15] && edid[0x16]) {
1292  		printk(BIOS_SPEW, "Maximum image size: %d cm x %d cm\n",
1293  		       edid[0x15], edid[0x16]);
1294  	} else if (c.claims_one_point_four && (edid[0x15] || edid[0x16])) {
1295  		if (edid[0x15]) { /* edid[0x15] != 0 && edid[0x16] == 0 */
1296  			unsigned int ratio = 100000/(edid[0x15] + 99);
1297  			printk(BIOS_SPEW,
1298  				"Aspect ratio is %u.%03u (landscape)\n",
1299  				ratio / 1000, ratio % 1000);
1300  		} else { /* edid[0x15] == 0 && edid[0x16] != 0 */
1301  			unsigned int ratio = 100000/(edid[0x16] + 99);
1302  			printk(BIOS_SPEW,
1303  				"Aspect ratio is %u.%03u (portrait)\n",
1304  				ratio / 1000, ratio % 1000);
1305  		}
1306  	} else {
1307  		/* Either or both can be zero for 1.3 and before */
1308  		printk(BIOS_SPEW, "Image size is variable\n");
1309  	}
1310  
1311  	if (edid[0x17] == 0xff) {
1312  		if (c.claims_one_point_four)
1313  			printk(BIOS_SPEW,
1314  				"Gamma is defined in an extension block\n");
1315  		else
1316  			/* XXX Technically 1.3 doesn't say this... */
1317  			printk(BIOS_SPEW, "Gamma: 1.0\n");
1318  	} else
1319  		printk(BIOS_SPEW, "Gamma: %d%%\n", ((edid[0x17] + 100)));
1320  	printk(BIOS_SPEW, "Check DPMS levels\n");
1321  	if (edid[0x18] & 0xE0) {
1322  		printk(BIOS_SPEW, "DPMS levels:");
1323  		if (edid[0x18] & 0x80)
1324  			printk(BIOS_SPEW, " Standby");
1325  		if (edid[0x18] & 0x40)
1326  			printk(BIOS_SPEW, " Suspend");
1327  		if (edid[0x18] & 0x20)
1328  			printk(BIOS_SPEW, " Off");
1329  		printk(BIOS_SPEW, "\n");
1330  	}
1331  
1332  	/* FIXME: this is from 1.4 spec, check earlier */
1333  	if (analog) {
1334  		switch (edid[0x18] & 0x18) {
1335  		case 0x00:
1336  			printk(BIOS_SPEW, "Monochrome or grayscale display\n");
1337  			break;
1338  		case 0x08:
1339  			printk(BIOS_SPEW, "RGB color display\n");
1340  			break;
1341  		case 0x10:
1342  			printk(BIOS_SPEW, "Non-RGB color display\n");
1343  			break;
1344  		case 0x18:
1345  			printk(BIOS_SPEW, "Undefined display color type\n");
1346  			break;
1347  		}
1348  	} else {
1349  		printk(BIOS_SPEW, "Supported color formats: RGB 4:4:4");
1350  		if (edid[0x18] & 0x10)
1351  			printk(BIOS_SPEW, ", YCrCb 4:4:4");
1352  		if (edid[0x18] & 0x08)
1353  			printk(BIOS_SPEW, ", YCrCb 4:2:2");
1354  		printk(BIOS_SPEW, "\n");
1355  	}
1356  
1357  	if (edid[0x18] & 0x04)
1358  		printk(BIOS_SPEW,
1359  			"Default (sRGB) color space is primary color space\n");
1360  	if (edid[0x18] & 0x02) {
1361  		printk(BIOS_SPEW,
1362  			"First detailed timing is preferred timing\n");
1363  		c.has_preferred_timing = 1;
1364  	}
1365  	if (edid[0x18] & 0x01)
1366  		printk(BIOS_SPEW,
1367  			"Supports GTF timings within operating range\n");
1368  
1369  	/* XXX color section */
1370  
1371  	printk(BIOS_SPEW, "Established timings supported:\n");
1372  	/* it's not yet clear we want all this stuff in the edid struct.
1373  	 * Let's wait.
1374  	 */
1375  	for (i = 0; i < 17; i++) {
1376  		if (edid[0x23 + i / 8] & (1 << (7 - i % 8))) {
1377  			printk(BIOS_SPEW, "  %dx%d@%dHz\n",
1378  				established_timings[i].x,
1379  				established_timings[i].y,
1380  				established_timings[i].refresh);
1381  
1382  			for (j = 0; j < NUM_KNOWN_MODES; j++) {
1383  				if (known_modes[j].ha ==
1384  						established_timings[i].x
1385  					&& known_modes[j].va ==
1386  						established_timings[i].y
1387  					&& known_modes[j].refresh ==
1388  						established_timings[i].refresh)
1389  					out->mode_is_supported[j] = 1;
1390  			}
1391  		}
1392  	}
1393  
1394  	printk(BIOS_SPEW, "Standard timings supported:\n");
1395  	for (i = 0; i < 8; i++) {
1396  		uint8_t b1 = edid[0x26 + i * 2], b2 = edid[0x26 + i * 2 + 1];
1397  		unsigned int x, y = 0, refresh;
1398  
1399  		if (b1 == 0x01 && b2 == 0x01)
1400  			continue;
1401  
1402  		if (b1 == 0) {
1403  			printk(BIOS_SPEW,
1404  				"non-conformant standard timing (0 horiz)\n");
1405  			continue;
1406  		}
1407  		x = (b1 + 31) * 8;
1408  		switch ((b2 >> 6) & 0x3) {
1409  		case 0x00:
1410  			if (c.claims_one_point_three)
1411  				y = x * 10 / 16;
1412  			else
1413  				y = x;
1414  			break;
1415  		case 0x01:
1416  			y = x * 3 / 4;
1417  			break;
1418  		case 0x02:
1419  			y = x * 4 / 5;
1420  			break;
1421  		case 0x03:
1422  			y = x * 9 / 16;
1423  			break;
1424  		}
1425  		refresh = 60 + (b2 & 0x3f);
1426  
1427  		printk(BIOS_SPEW, "  %dx%d@%dHz\n", x, y, refresh);
1428  		for (j = 0; j < NUM_KNOWN_MODES; j++) {
1429  			if (known_modes[j].ha == x && known_modes[j].va == y &&
1430  					known_modes[j].refresh == refresh)
1431  				out->mode_is_supported[j] = 1;
1432  		}
1433  	}
1434  
1435  	/* detailed timings */
1436  	printk(BIOS_SPEW, "Detailed timings\n");
1437  	for (i = 0; i < 4; i++) {
1438  		c.has_valid_detailed_blocks &= detailed_block(
1439  				out, edid + 0x36 + i * 18, 0, &c);
1440  		if (i == 0 && c.has_preferred_timing
1441  			&& !c.did_detailed_timing) {
1442  			/* not really accurate... */
1443  			c.has_preferred_timing = 0;
1444  		}
1445  	}
1446  
1447  	/* check this, 1.4 verification guide says otherwise */
1448  	if (edid[0x7e]) {
1449  		printk(BIOS_SPEW, "Has %d extension blocks\n", edid[0x7e]);
1450  		/* 2 is impossible because of the block map */
1451  		if (edid[0x7e] != 2)
1452  			c.has_valid_extension_count = 1;
1453  	} else {
1454  		c.has_valid_extension_count = 1;
1455  	}
1456  
1457  	printk(BIOS_SPEW, "Checksum\n");
1458  	c.has_valid_checksum = do_checksum(edid);
1459  
1460  	/* EDID v2.0 has a larger blob (256 bytes) and may have some problem in
1461  	 * the extension parsing loop below.  Since v2.0 was quickly deprecated
1462  	 * by v1.3 and we are unlikely to use any EDID 2.0 panels, we ignore
1463  	 * that case now and can fix it when we need to use a real 2.0 panel.
1464  	 */
1465  	for (i = 128; i < size; i += 128)
1466  		c.nonconformant_extension +=
1467  				parse_extension(out, &edid[i], &c);
1468  
1469  	if (c.claims_one_point_four) {
1470  		if (c.nonconformant_digital_display ||
1471  		    !c.has_valid_string_termination ||
1472  		    !c.has_valid_descriptor_pad ||
1473  			!c.has_preferred_timing) {
1474  			c.conformant = EDID_NOT_CONFORMANT;
1475  			printk(BIOS_ERR,
1476  				"EDID block does NOT conform to EDID 1.4!\n");
1477  		}
1478  
1479  		if (c.nonconformant_digital_display)
1480  			printk(BIOS_ERR,
1481  			       "\tDigital display field contains garbage: %x\n",
1482  			       c.nonconformant_digital_display);
1483  		if (!c.has_valid_string_termination)
1484  			printk(BIOS_ERR,
1485  			   "\tDetailed block string not properly terminated\n");
1486  		if (!c.has_valid_descriptor_pad)
1487  			printk(BIOS_ERR,
1488  				"\tInvalid descriptor block padding\n");
1489  		if (!c.has_preferred_timing)
1490  			printk(BIOS_ERR, "\tMissing preferred timing\n");
1491  	} else if (c.claims_one_point_three) {
1492  		if (c.nonconformant_digital_display ||
1493  		    !c.has_valid_string_termination ||
1494  		    !c.has_valid_descriptor_pad ||
1495  		    !c.has_preferred_timing) {
1496  			c.conformant = EDID_NOT_CONFORMANT;
1497  		}
1498  		/**
1499  		 * According to E-EDID (EDIDv1.3), has_name_descriptor and
1500  		 * has_range_descriptor are both required. These fields are
1501  		 * optional in v1.4. However some v1.3 panels (Ex, B133XTN01.3)
1502  		 * don't have them. As a workaround, we only print warning
1503  		 * messages.
1504  		 */
1505  		if (c.conformant == EDID_NOT_CONFORMANT)
1506  			printk(BIOS_ERR,
1507  				"EDID block does NOT conform to EDID 1.3!\n");
1508  		else if (!c.has_name_descriptor || !c.has_range_descriptor)
1509  			printk(BIOS_WARNING, "EDID block does NOT "
1510  			       "fully conform to EDID 1.3.\n");
1511  
1512  		if (c.nonconformant_digital_display)
1513  			printk(BIOS_ERR,
1514  			       "\tDigital display field contains garbage: %x\n",
1515  			       c.nonconformant_digital_display);
1516  		if (!c.has_name_descriptor)
1517  			printk(BIOS_ERR, "\tMissing name descriptor\n");
1518  		if (!c.has_preferred_timing)
1519  			printk(BIOS_ERR, "\tMissing preferred timing\n");
1520  		if (!c.has_range_descriptor)
1521  			printk(BIOS_ERR, "\tMissing monitor ranges\n");
1522  		/* Might be more than just 1.3 */
1523  		if (!c.has_valid_descriptor_pad)
1524  			printk(BIOS_ERR,
1525  				"\tInvalid descriptor block padding\n");
1526  		if (!c.has_valid_string_termination) /* Likewise */
1527  			printk(BIOS_ERR,
1528  			   "\tDetailed block string not properly terminated\n");
1529  	} else if (c.claims_one_point_two) {
1530  		if (c.nonconformant_digital_display ||
1531  			!c.has_valid_string_termination) {
1532  			c.conformant = EDID_NOT_CONFORMANT;
1533  			printk(BIOS_ERR,
1534  				"EDID block does NOT conform to EDID 1.2!\n");
1535  		}
1536  		if (c.nonconformant_digital_display)
1537  			printk(BIOS_ERR,
1538  			       "\tDigital display field contains garbage: %x\n",
1539  			       c.nonconformant_digital_display);
1540  		if (!c.has_valid_string_termination)
1541  			printk(BIOS_ERR,
1542  			   "\tDetailed block string not properly terminated\n");
1543  	} else if (c.claims_one_point_oh) {
1544  		if (c.seen_non_detailed_descriptor) {
1545  			c.conformant = EDID_NOT_CONFORMANT;
1546  			printk(BIOS_ERR,
1547  				"EDID block does NOT conform to EDID 1.0!\n");
1548  		}
1549  		if (c.seen_non_detailed_descriptor)
1550  			printk(BIOS_ERR,
1551  				"\tHas descriptor blocks other than detailed timings\n");
1552  	}
1553  
1554  	if (c.nonconformant_extension ||
1555  	    !c.has_valid_checksum ||
1556  	    !c.has_valid_cvt ||
1557  	    !c.has_valid_year ||
1558  	    !c.has_valid_week ||
1559  	    !c.has_valid_detailed_blocks ||
1560  	    !c.has_valid_dummy_block ||
1561  	    !c.has_valid_extension_count ||
1562  	    !c.has_valid_descriptor_ordering ||
1563  	    !c.has_valid_range_descriptor ||
1564  	    !c.manufacturer_name_well_formed) {
1565  		c.conformant = EDID_NOT_CONFORMANT;
1566  		printk(BIOS_ERR, "EDID block does not conform at all!\n");
1567  		if (c.nonconformant_extension)
1568  			printk(BIOS_ERR,
1569  				"\tHas %d nonconformant extension block(s)\n",
1570  			       c.nonconformant_extension);
1571  		if (!c.has_valid_checksum)
1572  			printk(BIOS_ERR, "\tBlock has broken checksum\n");
1573  		if (!c.has_valid_cvt)
1574  			printk(BIOS_ERR, "\tBroken 3-byte CVT blocks\n");
1575  		if (!c.has_valid_year)
1576  			printk(BIOS_ERR, "\tBad year of manufacture\n");
1577  		if (!c.has_valid_week)
1578  			printk(BIOS_ERR, "\tBad week of manufacture\n");
1579  		if (!c.has_valid_detailed_blocks)
1580  			printk(BIOS_ERR,
1581  				"\tDetailed blocks filled with garbage\n");
1582  		if (!c.has_valid_dummy_block)
1583  			printk(BIOS_ERR, "\tDummy block filled with garbage\n");
1584  		if (!c.has_valid_extension_count)
1585  			printk(BIOS_ERR,
1586  				"\tImpossible extension block count\n");
1587  		if (!c.manufacturer_name_well_formed)
1588  			printk(BIOS_ERR,
1589  				"\tManufacturer name field contains garbage\n");
1590  		if (!c.has_valid_descriptor_ordering)
1591  			printk(BIOS_ERR,
1592  			     "\tInvalid detailed timing descriptor ordering\n");
1593  		if (!c.has_valid_range_descriptor)
1594  			printk(BIOS_ERR,
1595  				"\tRange descriptor contains garbage\n");
1596  		if (!c.has_valid_max_dotclock)
1597  			printk(BIOS_ERR,
1598  				"\tEDID 1.4 block does not set max dotclock\n");
1599  	}
1600  
1601  	if (c.warning_excessive_dotclock_correction)
1602  		printk(BIOS_ERR,
1603  		       "Warning: CVT block corrects dotclock by more than 9.75MHz\n");
1604  	if (c.warning_zero_preferred_refresh)
1605  		printk(BIOS_ERR,
1606  		       "Warning: CVT block does not set preferred refresh rate\n");
1607  	return c.conformant;
1608  }
1609  
1610  /*
1611   * Notes on panel extensions: (TODO, implement me in the code)
1612   *
1613   * EPI: http://www.epi-standard.org/fileadmin/spec/EPI_Specification1.0.pdf
1614   * at offset 0x6c (fourth detailed block): (all other bits reserved)
1615   * 0x6c: 00 00 00 0e 00
1616   * 0x71: bit 6-5: data color mapping (00 conventional/fpdi/vesa, 01 openldi)
1617   *       bit 4-3: pixels per clock (00 1, 01 2, 10 4, 11 reserved)
1618   *       bit 2-0: bits per pixel (000 18, 001 24, 010 30, else reserved)
1619   * 0x72: bit 5: FPSCLK polarity (0 normal 1 inverted)
1620   *       bit 4: DE polarity (0 high active 1 low active)
1621   *       bit 3-0: interface (0000 LVDS TFT
1622   *                           0001 mono STN 4/8bit
1623   *                           0010 color STN 8/16 bit
1624   *                           0011 18 bit tft
1625   *                           0100 24 bit tft
1626   *                           0101 tmds
1627   *                           else reserved)
1628   * 0x73: bit 1: horizontal display mode (0 normal 1 right/left reverse)
1629   *       bit 0: vertical display mode (0 normal 1 up/down reverse)
1630   * 0x74: bit 7-4: total poweroff seq delay (0000 vga controller default
1631   *                                          else time in 10ms (10ms to 150ms))
1632   *       bit 3-0: total poweron seq delay (as above)
1633   * 0x75: contrast power on/off seq delay, same as 0x74
1634   * 0x76: bit 7: backlight control enable (1 means this field is valid)
1635   *       bit 6: backlight enabled at boot (0 on 1 off)
1636   *       bit 5-0: backlight brightness control steps (0..63)
1637   * 0x77: bit 7: contrast control, same bit pattern as 0x76 except bit 6 resvd
1638   * 0x78 - 0x7c: reserved
1639   * 0x7d: bit 7-4: EPI descriptor major version (1)
1640   *       bit 3-0: EPI descriptor minor version (0)
1641   *
1642   * ----
1643   *
1644   * SPWG: http://www.spwg.org/spwg_spec_version3.8_3-14-2007.pdf
1645   *
1646   * Since these are "dummy" blocks, terminate with 0a 20 20 20 ... as usual
1647   *
1648   * detailed descriptor 3:
1649   * 0x5a - 0x5e: 00 00 00 fe 00
1650   * 0x5f - 0x63: PC maker part number
1651   * 0x64: LCD supplier revision #
1652   * 0x65 - 0x6b: manufacturer part number
1653   *
1654   * detailed descriptor 4:
1655   * 0x6c - 0x70: 00 00 00 fe 00
1656   * 0x71 - 0x78: smbus nits values (whut)
1657   * 0x79: number of lvds channels (1 or 2)
1658   * 0x7A: panel self test (1 if present)
1659   * and then dummy terminator
1660   *
1661   * SPWG also says something strange about the LSB of detailed descriptor 1:
1662   * "LSB is set to "1" if panel is DE-timing only. H/V can be ignored."
1663   */
1664  
1665  /* Set the framebuffer bits-per-pixel, recalculating all dependent values. */
1666  void edid_set_framebuffer_bits_per_pixel(struct edid *edid, int fb_bpp,
1667  					 int row_byte_alignment)
1668  {
1669  	/* Caller should pass a supported value, everything else is BUG(). */
1670  	assert(fb_bpp == 32 || fb_bpp == 24 || fb_bpp == 16);
1671  	row_byte_alignment = MAX(row_byte_alignment, 1);
1672  
1673  	edid->framebuffer_bits_per_pixel = fb_bpp;
1674  	edid->bytes_per_line = ALIGN_UP(edid->mode.ha *
1675  		DIV_ROUND_UP(fb_bpp, 8), row_byte_alignment);
1676  	edid->x_resolution = edid->bytes_per_line / (fb_bpp / 8);
1677  	edid->y_resolution = edid->mode.va;
1678  }