xref: /openbsd/sys/dev/videomode/edid.c (revision 3bef86f7)
1 /* $NetBSD: edid.c,v 1.5 2007/03/07 19:56:40 macallan Exp $ */
2 
3 /*-
4  * Copyright (c) 2006 Itronix Inc.
5  * All rights reserved.
6  *
7  * Written by Garrett D'Amore for Itronix Inc.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. The name of Itronix Inc. may not be used to endorse
18  *    or promote products derived from this software without specific
19  *    prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY ITRONIX INC. ``AS IS'' AND ANY EXPRESS
22  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
23  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL ITRONIX INC. BE LIABLE FOR ANY
25  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
27  * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
30  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
31  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/device.h>
37 #include <sys/kernel.h>
38 #include <sys/malloc.h>
39 #include <dev/videomode/videomode.h>
40 #include <dev/videomode/ediddevs.h>
41 #include <dev/videomode/edidreg.h>
42 #include <dev/videomode/edidvar.h>
43 #include <dev/videomode/vesagtf.h>
44 
45 const char *edid_findvendor(const char *);
46 const char *edid_findproduct(const char *, uint16_t);
47 void edid_strchomp(char *);
48 const struct videomode *edid_mode_lookup_list(const char *);
49 int edid_std_timing(uint8_t *, struct videomode *);
50 int edid_det_timing(uint8_t *, struct videomode *);
51 void edid_block(struct edid_info *, uint8_t *);
52 
53 #define	EDIDVERBOSE	1
54 #define	DIVIDE(x,y)	(((x) + ((y) / 2)) / (y))
55 
56 static const char *_edid_modes[] =  {
57 	"1280x1024x75",
58 	"1024x768x75",
59 	"1024x768x70",
60 	"1024x768x60",
61 	"1024x768x87i",
62 	"832x768x74",	/* rounding error, 74.55 Hz aka "832x624x75" */
63 	"800x600x75",
64 	"800x600x72",
65 	"800x600x60",
66 	"800x600x56",
67 	"640x480x75",
68 	"640x480x72",
69 	"640x480x67",
70 	"640x480x60",
71 	"720x400x85",	/* should this really be "720x400x88" ? */
72 	"720x400x70",	/* hmm... videomode.c doesn't have this one */
73 };
74 
75 #ifdef	EDIDVERBOSE
76 struct edid_vendor {
77 	const char	*vendor;
78 	const char	*name;
79 };
80 
81 struct edid_product {
82 	const char	*vendor;
83 	uint16_t	product;
84 	const char	*name;
85 };
86 
87 #include <dev/videomode/ediddevs_data.h>
88 #endif	/* EDIDVERBOSE */
89 
90 const char *
91 edid_findvendor(const char *vendor)
92 {
93 #ifdef	EDIDVERBOSE
94 	int	n;
95 
96 	for (n = 0; n < edid_nvendors; n++)
97 		if (memcmp(edid_vendors[n].vendor, vendor, 3) == 0)
98 			return (edid_vendors[n].name);
99 #endif
100 	return NULL;
101 }
102 
103 const char *
104 edid_findproduct(const char *vendor, uint16_t product)
105 {
106 #ifdef	EDIDVERBOSE
107 	int	n;
108 
109 	for (n = 0; n < edid_nproducts; n++)
110 		if ((edid_products[n].product == product) &&
111 		    (memcmp(edid_products[n].vendor, vendor, 3) == 0))
112 			return (edid_products[n].name);
113 #endif	/* EDIDVERBOSE */
114 	return NULL;
115 
116 }
117 
118 void
119 edid_strchomp(char *ptr)
120 {
121 	for (;;) {
122 		switch (*ptr) {
123 		case 0:
124 			return;
125 		case '\r':
126 		case '\n':
127 			*ptr = 0;
128 			return;
129 		}
130 		ptr++;
131 	}
132 }
133 
134 int
135 edid_is_valid(uint8_t *d)
136 {
137 	int sum = 0, i;
138 	uint8_t sig[8] = EDID_SIGNATURE;
139 
140 	if (memcmp(d, sig, 8) != 0)
141 		return EINVAL;
142 
143 	for (i = 0; i < 128; i++)
144 		sum += d[i];
145 	if ((sum & 0xff) != 0)
146 		return EINVAL;
147 
148 	return 0;
149 }
150 
151 void
152 edid_print(struct edid_info *edid)
153 {
154 	int	i;
155 
156 	if (edid == NULL)
157 		return;
158 	printf("Vendor: [%s] %s\n", edid->edid_vendor, edid->edid_vendorname);
159 	printf("Product: [%04X] %s\n", edid->edid_product,
160 	    edid->edid_productname);
161 	printf("Serial number: %s\n", edid->edid_serial);
162 	printf("Manufactured %d Week %d\n",
163 	    edid->edid_year, edid->edid_week);
164 	printf("EDID Version %d.%d\n", edid->edid_version,
165 	    edid->edid_revision);
166 	printf("EDID Comment: %s\n", edid->edid_comment);
167 
168 	printf("Video Input: %x\n", edid->edid_video_input);
169 	if (edid->edid_video_input & EDID_VIDEO_INPUT_DIGITAL) {
170 		printf("\tDigital");
171 		if (edid->edid_video_input & EDID_VIDEO_INPUT_DFP1_COMPAT)
172 			printf(" (DFP 1.x compatible)");
173 		printf("\n");
174 	} else {
175 		printf("\tAnalog\n");
176 		switch (EDID_VIDEO_INPUT_LEVEL(edid->edid_video_input)) {
177 		case 0:
178 			printf("\t-0.7, 0.3V\n");
179 			break;
180 		case 1:
181 			printf("\t-0.714, 0.286V\n");
182 			break;
183 		case 2:
184 			printf("\t-1.0, 0.4V\n");
185 			break;
186 		case 3:
187 			printf("\t-0.7, 0.0V\n");
188 			break;
189 		}
190 		if (edid->edid_video_input & EDID_VIDEO_INPUT_BLANK_TO_BLACK)
191 			printf("\tBlank-to-black setup\n");
192 		if (edid->edid_video_input & EDID_VIDEO_INPUT_SEPARATE_SYNCS)
193 			printf("\tSeperate syncs\n");
194 		if (edid->edid_video_input & EDID_VIDEO_INPUT_COMPOSITE_SYNC)
195 			printf("\tComposite sync\n");
196 		if (edid->edid_video_input & EDID_VIDEO_INPUT_SYNC_ON_GRN)
197 			printf("\tSync on green\n");
198 		if (edid->edid_video_input & EDID_VIDEO_INPUT_SERRATION)
199 			printf("\tSerration vsync\n");
200 	}
201 
202 	printf("Gamma: %d.%02d\n",
203 	    edid->edid_gamma / 100, edid->edid_gamma % 100);
204 
205 	printf("Max Size: %d cm x %d cm\n",
206 	    edid->edid_max_hsize, edid->edid_max_vsize);
207 
208 	printf("Features: %x\n", edid->edid_features);
209 	if (edid->edid_features & EDID_FEATURES_STANDBY)
210 		printf("\tDPMS standby\n");
211 	if (edid->edid_features & EDID_FEATURES_SUSPEND)
212 		printf("\tDPMS suspend\n");
213 	if (edid->edid_features & EDID_FEATURES_ACTIVE_OFF)
214 		printf("\tDPMS active-off\n");
215 	switch (EDID_FEATURES_DISP_TYPE(edid->edid_features)) {
216 	case EDID_FEATURES_DISP_TYPE_MONO:
217 		printf("\tMonochrome\n");
218 		break;
219 	case EDID_FEATURES_DISP_TYPE_RGB:
220 		printf("\tRGB\n");
221 		break;
222 	case EDID_FEATURES_DISP_TYPE_NON_RGB:
223 		printf("\tMulticolor\n");
224 		break;
225 	case EDID_FEATURES_DISP_TYPE_UNDEFINED:
226 		printf("\tUndefined monitor type\n");
227 		break;
228 	}
229 	if (edid->edid_features & EDID_FEATURES_STD_COLOR)
230 		printf("\tStandard color space\n");
231 	if (edid->edid_features & EDID_FEATURES_PREFERRED_TIMING)
232 		printf("\tPreferred timing\n");
233 	if (edid->edid_features & EDID_FEATURES_DEFAULT_GTF)
234 		printf("\tDefault GTF supported\n");
235 
236 	printf("Chroma Info:\n");
237 	printf("\tRed X: 0.%03d\n", edid->edid_chroma.ec_redx);
238 	printf("\tRed Y: 0.%03d\n", edid->edid_chroma.ec_redy);
239 	printf("\tGrn X: 0.%03d\n", edid->edid_chroma.ec_greenx);
240 	printf("\tGrn Y: 0.%03d\n", edid->edid_chroma.ec_greeny);
241 	printf("\tBlu X: 0.%03d\n", edid->edid_chroma.ec_bluex);
242 	printf("\tBlu Y: 0.%03d\n", edid->edid_chroma.ec_bluey);
243 	printf("\tWht X: 0.%03d\n", edid->edid_chroma.ec_whitex);
244 	printf("\tWht Y: 0.%03d\n", edid->edid_chroma.ec_whitey);
245 
246 	if (edid->edid_have_range) {
247 		printf("Range:\n");
248 		printf("\tHorizontal: %d - %d kHz\n",
249 		    edid->edid_range.er_min_hfreq,
250 		    edid->edid_range.er_max_hfreq);
251 		printf("\tVertical: %d - %d Hz\n",
252 		    edid->edid_range.er_min_vfreq,
253 		    edid->edid_range.er_max_vfreq);
254 		printf("\tMax Dot Clock: %d MHz\n",
255 		    edid->edid_range.er_max_clock);
256 		if (edid->edid_range.er_have_gtf2) {
257 			printf("\tGTF2 hfreq: %d\n",
258 			    edid->edid_range.er_gtf2_hfreq);
259 			printf("\tGTF2 C: %d\n", edid->edid_range.er_gtf2_c);
260 			printf("\tGTF2 M: %d\n", edid->edid_range.er_gtf2_m);
261 			printf("\tGTF2 J: %d\n", edid->edid_range.er_gtf2_j);
262 			printf("\tGTF2 K: %d\n", edid->edid_range.er_gtf2_k);
263 		}
264 	}
265 	printf("Video modes:\n");
266 	for (i = 0; i < edid->edid_nmodes; i++) {
267 		printf("\t%dx%d @ %dHz\n",
268 		    edid->edid_modes[i].hdisplay,
269 		    edid->edid_modes[i].vdisplay,
270 		    DIVIDE(DIVIDE(edid->edid_modes[i].dot_clock * 1000,
271 			       edid->edid_modes[i].htotal),
272 			edid->edid_modes[i].vtotal));
273 	}
274 	if (edid->edid_preferred_mode)
275 		printf("Preferred mode: %dx%d @ %dHz\n",
276 		    edid->edid_preferred_mode->hdisplay,
277 		    edid->edid_preferred_mode->vdisplay,
278 		    DIVIDE(DIVIDE(edid->edid_preferred_mode->dot_clock * 1000,
279 			       edid->edid_preferred_mode->htotal),
280 			edid->edid_preferred_mode->vtotal));
281 }
282 
283 const struct videomode *
284 edid_mode_lookup_list(const char *name)
285 {
286 	int	i;
287 
288 	for (i = 0; i < videomode_count; i++)
289 		if (strcmp(name, videomode_list[i].name) == 0)
290 			return &videomode_list[i];
291 	return NULL;
292 }
293 
294 int
295 edid_std_timing(uint8_t *data, struct videomode *vmp)
296 {
297 	unsigned			x, y, f;
298 	const struct videomode		*lookup;
299 	char				name[80];
300 
301 	if ((data[0] == 1 && data[1] == 1) ||
302 	    (data[0] == 0 && data[1] == 0) ||
303 	    (data[0] == 0x20 && data[1] == 0x20))
304 		return 0;
305 
306 	x = EDID_STD_TIMING_HRES(data);
307 	switch (EDID_STD_TIMING_RATIO(data)) {
308 	case EDID_STD_TIMING_RATIO_16_10:
309 		y = x * 10 / 16;
310 		break;
311 	case EDID_STD_TIMING_RATIO_4_3:
312 		y = x * 3 / 4;
313 		break;
314 	case EDID_STD_TIMING_RATIO_5_4:
315 		y = x * 4 / 5;
316 		break;
317 	case EDID_STD_TIMING_RATIO_16_9:
318 	default:
319 		y = x * 9 / 16;
320 		break;
321 	}
322 	f = EDID_STD_TIMING_VFREQ(data);
323 
324 	/* first try to lookup the mode as a DMT timing */
325 	snprintf(name, sizeof (name), "%dx%dx%d", x, y, f);
326 	if ((lookup = edid_mode_lookup_list(name)) != NULL) {
327 		*vmp = *lookup;
328 	}
329 
330 	/* failing that, calculate it using gtf */
331 	else {
332 		/*
333 		 * Hmm. I'm not using alternate GTF timings, which
334 		 * could, in theory, be present.
335 		 */
336 		vesagtf_mode(x, y, f, vmp);
337 	}
338 	return 1;
339 }
340 
341 int
342 edid_det_timing(uint8_t *data, struct videomode *vmp)
343 {
344 	unsigned	hactive, hblank, hsyncwid, hsyncoff;
345 	unsigned	vactive, vblank, vsyncwid, vsyncoff;
346 	uint8_t		flags;
347 
348 	flags = EDID_DET_TIMING_FLAGS(data);
349 
350 	/* we don't support stereo modes (for now) */
351 	if (flags & (EDID_DET_TIMING_FLAG_STEREO |
352 		EDID_DET_TIMING_FLAG_STEREO1))
353 		return 0;
354 
355 	vmp->dot_clock = EDID_DET_TIMING_DOT_CLOCK(data) / 1000;
356 
357 	hactive = EDID_DET_TIMING_HACTIVE(data);
358 	hblank = EDID_DET_TIMING_HBLANK(data);
359 	hsyncwid = EDID_DET_TIMING_HSYNC_WIDTH(data);
360 	hsyncoff = EDID_DET_TIMING_HSYNC_OFFSET(data);
361 
362 	vactive = EDID_DET_TIMING_VACTIVE(data);
363 	vblank = EDID_DET_TIMING_VBLANK(data);
364 	vsyncwid = EDID_DET_TIMING_VSYNC_WIDTH(data);
365 	vsyncoff = EDID_DET_TIMING_VSYNC_OFFSET(data);
366 
367 	/* XXX: I'm not doing anything with the borders, should I? */
368 
369 	vmp->hdisplay = hactive;
370 	vmp->htotal = hactive + hblank;
371 	vmp->hsync_start = hactive + hsyncoff;
372 	vmp->hsync_end = vmp->hsync_start + hsyncwid;
373 
374 	vmp->vdisplay = vactive;
375 	vmp->vtotal = vactive + vblank;
376 	vmp->vsync_start = vactive + vsyncoff;
377 	vmp->vsync_end = vmp->vsync_start + vsyncwid;
378 
379 	vmp->flags = 0;
380 
381 	if (flags & EDID_DET_TIMING_FLAG_INTERLACE)
382 		vmp->flags |= VID_INTERLACE;
383 	if (flags & EDID_DET_TIMING_FLAG_HSYNC_POSITIVE)
384 		vmp->flags |= VID_PHSYNC;
385 	else
386 		vmp->flags |= VID_NHSYNC;
387 
388 	if (flags & EDID_DET_TIMING_FLAG_VSYNC_POSITIVE)
389 		vmp->flags |= VID_PVSYNC;
390 	else
391 		vmp->flags |= VID_NVSYNC;
392 
393 	return 1;
394 }
395 
396 void
397 edid_block(struct edid_info *edid, uint8_t *data)
398 {
399 	int			i;
400 	struct videomode	mode;
401 
402 	if (EDID_BLOCK_IS_DET_TIMING(data)) {
403 		if (edid_det_timing(data, &mode)) {
404 			edid->edid_modes[edid->edid_nmodes] = mode;
405 			if (edid->edid_preferred_mode == NULL) {
406 				edid->edid_preferred_mode =
407 				    &edid->edid_modes[edid->edid_nmodes];
408 			}
409 			edid->edid_nmodes++;
410 		}
411 		return;
412 	}
413 
414 	switch (EDID_BLOCK_TYPE(data)) {
415 	case EDID_DESC_BLOCK_TYPE_SERIAL:
416 		memcpy(edid->edid_serial,
417 		    data + EDID_DESC_ASCII_DATA_OFFSET,
418 		    EDID_DESC_ASCII_DATA_LEN);
419 		edid->edid_serial[sizeof (edid->edid_serial) - 1] = 0;
420 		break;
421 
422 	case EDID_DESC_BLOCK_TYPE_ASCII:
423 		memcpy(edid->edid_comment,
424 		    data + EDID_DESC_ASCII_DATA_OFFSET,
425 		    EDID_DESC_ASCII_DATA_LEN);
426 		edid->edid_comment[sizeof (edid->edid_comment) - 1] = 0;
427 		break;
428 
429 	case EDID_DESC_BLOCK_TYPE_RANGE:
430 		edid->edid_have_range = 1;
431 		edid->edid_range.er_min_vfreq =
432 		    EDID_DESC_RANGE_MIN_VFREQ(data);
433 		edid->edid_range.er_max_vfreq =
434 		    EDID_DESC_RANGE_MAX_VFREQ(data);
435 		edid->edid_range.er_min_hfreq =
436 		    EDID_DESC_RANGE_MIN_HFREQ(data);
437 		edid->edid_range.er_max_hfreq =
438 		    EDID_DESC_RANGE_MAX_HFREQ(data);
439 		edid->edid_range.er_max_clock =
440 		    EDID_DESC_RANGE_MAX_CLOCK(data);
441 		if (EDID_DESC_RANGE_HAVE_GTF2(data)) {
442 			edid->edid_range.er_have_gtf2 = 1;
443 			edid->edid_range.er_gtf2_hfreq =
444 			    EDID_DESC_RANGE_GTF2_HFREQ(data);
445 			edid->edid_range.er_gtf2_c =
446 			    EDID_DESC_RANGE_GTF2_C(data);
447 			edid->edid_range.er_gtf2_m =
448 			    EDID_DESC_RANGE_GTF2_M(data);
449 			edid->edid_range.er_gtf2_j =
450 			    EDID_DESC_RANGE_GTF2_J(data);
451 			edid->edid_range.er_gtf2_k =
452 			    EDID_DESC_RANGE_GTF2_K(data);
453 		}
454 		break;
455 
456 	case EDID_DESC_BLOCK_TYPE_NAME:
457 		/* copy the product name into place */
458 		memcpy(edid->edid_productname,
459 		    data + EDID_DESC_ASCII_DATA_OFFSET,
460 		    EDID_DESC_ASCII_DATA_LEN);
461 		break;
462 
463 	case EDID_DESC_BLOCK_TYPE_STD_TIMING:
464 		data += EDID_DESC_STD_TIMING_START;
465 		for (i = 0; i < EDID_DESC_STD_TIMING_COUNT; i++) {
466 			if (edid_std_timing(data, &mode)) {
467 				edid->edid_modes[edid->edid_nmodes] = mode;
468 				edid->edid_nmodes++;
469 			}
470 			data += 2;
471 		}
472 		break;
473 
474 	case EDID_DESC_BLOCK_TYPE_COLOR_POINT:
475 		/* XXX: not implemented yet */
476 		break;
477 	}
478 }
479 
480 /*
481  * Gets EDID version in BCD, e.g. EDID v1.3  returned as 0x0103
482  */
483 int
484 edid_parse(uint8_t *data, struct edid_info *edid)
485 {
486 	uint16_t		manfid, estmodes;
487 	const struct videomode	*vmp;
488 	int			i;
489 	const char		*name;
490 	int max_dotclock = 0;
491 	int mhz;
492 
493 	if (edid_is_valid(data) != 0)
494 		return -1;
495 
496 	/* get product identification */
497 	manfid = EDID_VENDOR_ID(data);
498 	edid->edid_vendor[0] = EDID_MANFID_0(manfid);
499 	edid->edid_vendor[1] = EDID_MANFID_1(manfid);
500 	edid->edid_vendor[2] = EDID_MANFID_2(manfid);
501 	edid->edid_vendor[3] = 0;	/* null terminate for convenience */
502 
503 	edid->edid_product = data[EDID_OFFSET_PRODUCT_ID] +
504 	    (data[EDID_OFFSET_PRODUCT_ID + 1] << 8);
505 
506 	name = edid_findvendor(edid->edid_vendor);
507 	if (name != NULL) {
508 		snprintf(edid->edid_vendorname,
509 		    sizeof (edid->edid_vendorname), "%s", name);
510 	}
511 	edid->edid_vendorname[sizeof (edid->edid_vendorname) - 1] = 0;
512 
513 	name = edid_findproduct(edid->edid_vendor, edid->edid_product);
514 	if (name != NULL) {
515 		snprintf(edid->edid_productname,
516 		    sizeof (edid->edid_productname), "%s", name);
517 	}
518 	edid->edid_productname[sizeof (edid->edid_productname) - 1] = 0;
519 
520 	snprintf(edid->edid_serial, sizeof (edid->edid_serial), "%08x",
521 	    EDID_SERIAL_NUMBER(data));
522 
523 	edid->edid_week = EDID_WEEK(data);
524 	edid->edid_year = EDID_YEAR(data);
525 
526 	/* get edid revision */
527 	edid->edid_version = EDID_VERSION(data);
528 	edid->edid_revision = EDID_REVISION(data);
529 
530 	edid->edid_video_input = EDID_VIDEO_INPUT(data);
531 	edid->edid_max_hsize = EDID_MAX_HSIZE(data);
532 	edid->edid_max_vsize = EDID_MAX_VSIZE(data);
533 
534 	edid->edid_gamma = EDID_GAMMA(data);
535 	edid->edid_features = EDID_FEATURES(data);
536 
537 	edid->edid_chroma.ec_redx = EDID_CHROMA_REDX(data);
538 	edid->edid_chroma.ec_redy = EDID_CHROMA_REDX(data);
539 	edid->edid_chroma.ec_greenx = EDID_CHROMA_GREENX(data);
540 	edid->edid_chroma.ec_greeny = EDID_CHROMA_GREENY(data);
541 	edid->edid_chroma.ec_bluex = EDID_CHROMA_BLUEX(data);
542 	edid->edid_chroma.ec_bluey = EDID_CHROMA_BLUEY(data);
543 	edid->edid_chroma.ec_whitex = EDID_CHROMA_WHITEX(data);
544 	edid->edid_chroma.ec_whitey = EDID_CHROMA_WHITEY(data);
545 
546 	/* lookup established modes */
547 	edid->edid_nmodes = 0;
548 	edid->edid_preferred_mode = NULL;
549 	estmodes = EDID_EST_TIMING(data);
550 	for (i = 0; i < 16; i++) {
551 		if (estmodes & (1 << i)) {
552 			vmp = edid_mode_lookup_list(_edid_modes[i]);
553 			if (vmp != NULL) {
554 				edid->edid_modes[edid->edid_nmodes] = *vmp;
555 				edid->edid_nmodes++;
556 			}
557 #ifdef DIAGNOSTIC
558 			  else
559 				printf("no data for est. mode %s\n",
560 				    _edid_modes[i]);
561 #endif
562 		}
563 	}
564 
565 	/* do standard timing section */
566 	for (i = 0; i < EDID_STD_TIMING_COUNT; i++) {
567 		struct videomode	mode;
568 		if (edid_std_timing(data + EDID_OFFSET_STD_TIMING + i * 2,
569 			&mode)) {
570 			edid->edid_modes[edid->edid_nmodes] = mode;
571 			edid->edid_nmodes++;
572 		}
573 	}
574 	/* do detailed timings and descriptors */
575 	for (i = 0; i < EDID_BLOCK_COUNT; i++) {
576 		edid_block(edid, data + EDID_OFFSET_DESC_BLOCK +
577 		    i * EDID_BLOCK_SIZE);
578 	}
579 
580 	edid_strchomp(edid->edid_vendorname);
581 	edid_strchomp(edid->edid_productname);
582 	edid_strchomp(edid->edid_serial);
583 	edid_strchomp(edid->edid_comment);
584 
585 	/*
586 	 * XXX
587 	 * some monitors lie about their maximum supported dot clock
588 	 * by claiming to support modes which need a higher dot clock
589 	 * than the stated maximum.
590 	 * For sanity's sake we bump it to the highest dot clock we find
591 	 * in the list of supported modes
592 	 */
593 	for (i = 0; i < edid->edid_nmodes; i++)
594 		if (edid->edid_modes[i].dot_clock > max_dotclock)
595 			max_dotclock = edid->edid_modes[i].dot_clock;
596 
597 	printf("max_dotclock according to supported modes: %d\n",
598 	    max_dotclock);
599 
600 	mhz = (max_dotclock + 999) / 1000;
601 
602 	if (edid->edid_have_range) {
603 
604 		if (mhz > edid->edid_range.er_max_clock)
605 			edid->edid_range.er_max_clock = mhz;
606 	} else
607 		edid->edid_range.er_max_clock = mhz;
608 
609 	return 0;
610 }
611 
612