xref: /netbsd-src/sys/dev/videomode/edid.c (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /* $NetBSD: edid.c,v 1.6 2009/11/14 09:19:41 tsutsui 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/cdefs.h>
35 __KERNEL_RCSID(0, "$NetBSD: edid.c,v 1.6 2009/11/14 09:19:41 tsutsui Exp $");
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/device.h>
40 #include <sys/kernel.h>
41 #include <sys/malloc.h>
42 #include <dev/videomode/videomode.h>
43 #include <dev/videomode/ediddevs.h>
44 #include <dev/videomode/edidreg.h>
45 #include <dev/videomode/edidvar.h>
46 #include <dev/videomode/vesagtf.h>
47 
48 #define	EDIDVERBOSE	1
49 #define	DIVIDE(x,y)	(((x) + ((y) / 2)) / (y))
50 
51 static const char *_edid_modes[] =  {
52 	"1280x1024x75",
53 	"1024x768x75",
54 	"1024x768x70",
55 	"1024x768x60",
56 	"1024x768x87i",
57 	"832x768x74",	/* rounding error, 74.55 Hz aka "832x624x75" */
58 	"800x600x75",
59 	"800x600x72",
60 	"800x600x60",
61 	"800x600x56",
62 	"640x480x75",
63 	"640x480x72",
64 	"640x480x67",
65 	"640x480x60",
66 	"720x400x85",	/* should this really be "720x400x88" ? */
67 	"720x400x70",	/* hmm... videmode.c doesn't have this one */
68 };
69 
70 #ifdef	EDIDVERBOSE
71 struct edid_vendor {
72 	const char	*vendor;
73 	const char	*name;
74 };
75 
76 struct edid_product {
77 	const char	*vendor;
78 	uint16_t	product;
79 	const char	*name;
80 };
81 
82 #include <dev/videomode/ediddevs_data.h>
83 #endif	/* EDIDVERBOSE */
84 
85 static const char *
86 edid_findvendor(const char *vendor)
87 {
88 #ifdef	EDIDVERBOSE
89 	int	n;
90 
91 	for (n = 0; n < edid_nvendors; n++)
92 		if (memcmp(edid_vendors[n].vendor, vendor, 3) == 0)
93 			return (edid_vendors[n].name);
94 #endif
95 	return NULL;
96 }
97 
98 static const char *
99 edid_findproduct(const char *vendor, uint16_t product)
100 {
101 #ifdef	EDIDVERBOSE
102 	int	n;
103 
104 	for (n = 0; n < edid_nproducts; n++)
105 		if ((edid_products[n].product == product) &&
106 		    (memcmp(edid_products[n].vendor, vendor, 3) == 0))
107 			return (edid_products[n].name);
108 #endif	/* EDIDVERBOSE */
109 	return NULL;
110 
111 }
112 
113 static void
114 edid_strchomp(char *ptr)
115 {
116 	for (;;) {
117 		switch (*ptr) {
118 		case 0:
119 			return;
120 		case '\r':
121 		case '\n':
122 			*ptr = 0;
123 			return;
124 		}
125 		ptr++;
126 	}
127 }
128 
129 int
130 edid_is_valid(uint8_t *d)
131 {
132 	int sum = 0, i;
133 	uint8_t sig[8] = EDID_SIGNATURE;
134 
135 	if (memcmp(d, sig, 8) != 0)
136 		return EINVAL;
137 
138 	for (i = 0; i < 128; i++)
139 		sum += d[i];
140 	if ((sum & 0xff) != 0)
141 		return EINVAL;
142 
143 	return 0;
144 }
145 
146 void
147 edid_print(struct edid_info *edid)
148 {
149 	int	i;
150 
151 	if (edid == NULL)
152 		return;
153 	printf("Vendor: [%s] %s\n", edid->edid_vendor, edid->edid_vendorname);
154 	printf("Product: [%04X] %s\n", edid->edid_product,
155 	    edid->edid_productname);
156 	printf("Serial number: %s\n", edid->edid_serial);
157 	printf("Manufactured %d Week %d\n",
158 	    edid->edid_year, edid->edid_week);
159 	printf("EDID Version %d.%d\n", edid->edid_version,
160 	    edid->edid_revision);
161 	printf("EDID Comment: %s\n", edid->edid_comment);
162 
163 	printf("Video Input: %x\n", edid->edid_video_input);
164 	if (edid->edid_video_input & EDID_VIDEO_INPUT_DIGITAL) {
165 		printf("\tDigital");
166 		if (edid->edid_video_input & EDID_VIDEO_INPUT_DFP1_COMPAT)
167 			printf(" (DFP 1.x compatible)");
168 		printf("\n");
169 	} else {
170 		printf("\tAnalog\n");
171 		switch (EDID_VIDEO_INPUT_LEVEL(edid->edid_video_input)) {
172 		case 0:
173 			printf("\t-0.7, 0.3V\n");
174 			break;
175 		case 1:
176 			printf("\t-0.714, 0.286V\n");
177 			break;
178 		case 2:
179 			printf("\t-1.0, 0.4V\n");
180 			break;
181 		case 3:
182 			printf("\t-0.7, 0.0V\n");
183 			break;
184 		}
185 		if (edid->edid_video_input & EDID_VIDEO_INPUT_BLANK_TO_BLACK)
186 			printf("\tBlank-to-black setup\n");
187 		if (edid->edid_video_input & EDID_VIDEO_INPUT_SEPARATE_SYNCS)
188 			printf("\tSeperate syncs\n");
189 		if (edid->edid_video_input & EDID_VIDEO_INPUT_COMPOSITE_SYNC)
190 			printf("\tComposite sync\n");
191 		if (edid->edid_video_input & EDID_VIDEO_INPUT_SYNC_ON_GRN)
192 			printf("\tSync on green\n");
193 		if (edid->edid_video_input & EDID_VIDEO_INPUT_SERRATION)
194 			printf("\tSerration vsync\n");
195 	}
196 
197 	printf("Gamma: %d.%02d\n",
198 	    edid->edid_gamma / 100, edid->edid_gamma % 100);
199 
200 	printf("Max Size: %d cm x %d cm\n",
201 	    edid->edid_max_hsize, edid->edid_max_vsize);
202 
203 	printf("Features: %x\n", edid->edid_features);
204 	if (edid->edid_features & EDID_FEATURES_STANDBY)
205 		printf("\tDPMS standby\n");
206 	if (edid->edid_features & EDID_FEATURES_SUSPEND)
207 		printf("\tDPMS suspend\n");
208 	if (edid->edid_features & EDID_FEATURES_ACTIVE_OFF)
209 		printf("\tDPMS active-off\n");
210 	switch (EDID_FEATURES_DISP_TYPE(edid->edid_features)) {
211 	case EDID_FEATURES_DISP_TYPE_MONO:
212 		printf("\tMonochrome\n");
213 		break;
214 	case EDID_FEATURES_DISP_TYPE_RGB:
215 		printf("\tRGB\n");
216 		break;
217 	case EDID_FEATURES_DISP_TYPE_NON_RGB:
218 		printf("\tMulticolor\n");
219 		break;
220 	case EDID_FEATURES_DISP_TYPE_UNDEFINED:
221 		printf("\tUndefined monitor type\n");
222 		break;
223 	}
224 	if (edid->edid_features & EDID_FEATURES_STD_COLOR)
225 		printf("\tStandard color space\n");
226 	if (edid->edid_features & EDID_FEATURES_PREFERRED_TIMING)
227 		printf("\tPreferred timing\n");
228 	if (edid->edid_features & EDID_FEATURES_DEFAULT_GTF)
229 		printf("\tDefault GTF supported\n");
230 
231 	printf("Chroma Info:\n");
232 	printf("\tRed X: 0.%03d\n", edid->edid_chroma.ec_redx);
233 	printf("\tRed Y: 0.%03d\n", edid->edid_chroma.ec_redy);
234 	printf("\tGrn X: 0.%03d\n", edid->edid_chroma.ec_greenx);
235 	printf("\tGrn Y: 0.%03d\n", edid->edid_chroma.ec_greeny);
236 	printf("\tBlu X: 0.%03d\n", edid->edid_chroma.ec_bluex);
237 	printf("\tBlu Y: 0.%03d\n", edid->edid_chroma.ec_bluey);
238 	printf("\tWht X: 0.%03d\n", edid->edid_chroma.ec_whitex);
239 	printf("\tWht Y: 0.%03d\n", edid->edid_chroma.ec_whitey);
240 
241 	if (edid->edid_have_range) {
242 		printf("Range:\n");
243 		printf("\tHorizontal: %d - %d kHz\n",
244 		    edid->edid_range.er_min_hfreq,
245 		    edid->edid_range.er_max_hfreq);
246 		printf("\tVertical: %d - %d Hz\n",
247 		    edid->edid_range.er_min_vfreq,
248 		    edid->edid_range.er_max_vfreq);
249 		printf("\tMax Dot Clock: %d MHz\n",
250 		    edid->edid_range.er_max_clock);
251 		if (edid->edid_range.er_have_gtf2) {
252 			printf("\tGTF2 hfreq: %d\n",
253 			    edid->edid_range.er_gtf2_hfreq);
254 			printf("\tGTF2 C: %d\n", edid->edid_range.er_gtf2_c);
255 			printf("\tGTF2 M: %d\n", edid->edid_range.er_gtf2_m);
256 			printf("\tGTF2 J: %d\n", edid->edid_range.er_gtf2_j);
257 			printf("\tGTF2 K: %d\n", edid->edid_range.er_gtf2_k);
258 		}
259 	}
260 	printf("Video modes:\n");
261 	for (i = 0; i < edid->edid_nmodes; i++) {
262 		printf("\t%dx%d @ %dHz\n",
263 		    edid->edid_modes[i].hdisplay,
264 		    edid->edid_modes[i].vdisplay,
265 		    DIVIDE(DIVIDE(edid->edid_modes[i].dot_clock * 1000,
266 			       edid->edid_modes[i].htotal),
267 			edid->edid_modes[i].vtotal));
268 	}
269 	if (edid->edid_preferred_mode)
270 		printf("Preferred mode: %dx%d @ %dHz\n",
271 		    edid->edid_preferred_mode->hdisplay,
272 		    edid->edid_preferred_mode->vdisplay,
273 		    DIVIDE(DIVIDE(edid->edid_preferred_mode->dot_clock * 1000,
274 			       edid->edid_preferred_mode->htotal),
275 			edid->edid_preferred_mode->vtotal));
276 }
277 
278 static const struct videomode *
279 edid_mode_lookup_list(const char *name)
280 {
281 	int	i;
282 
283 	for (i = 0; i < videomode_count; i++)
284 		if (strcmp(name, videomode_list[i].name) == 0)
285 			return &videomode_list[i];
286 	return NULL;
287 }
288 
289 static int
290 edid_std_timing(uint8_t *data, struct videomode *vmp)
291 {
292 	unsigned			x, y, f;
293 	const struct videomode		*lookup;
294 	char				name[80];
295 
296 	if ((data[0] == 1 && data[1] == 1) ||
297 	    (data[0] == 0 && data[1] == 0) ||
298 	    (data[0] == 0x20 && data[1] == 0x20))
299 		return 0;
300 
301 	x = EDID_STD_TIMING_HRES(data);
302 	switch (EDID_STD_TIMING_RATIO(data)) {
303 	case EDID_STD_TIMING_RATIO_16_10:
304 		y = x * 10 / 16;
305 		break;
306 	case EDID_STD_TIMING_RATIO_4_3:
307 		y = x * 3 / 4;
308 		break;
309 	case EDID_STD_TIMING_RATIO_5_4:
310 		y = x * 4 / 5;
311 		break;
312 	case EDID_STD_TIMING_RATIO_16_9:
313 	default:
314 		y = x * 9 / 16;
315 		break;
316 	}
317 	f = EDID_STD_TIMING_VFREQ(data);
318 
319 	/* first try to lookup the mode as a DMT timing */
320 	snprintf(name, sizeof (name), "%dx%dx%d", x, y, f);
321 	if ((lookup = edid_mode_lookup_list(name)) != NULL) {
322 		*vmp = *lookup;
323 	}
324 
325 	/* failing that, calculate it using gtf */
326 	else {
327 		/*
328 		 * Hmm. I'm not using alternate GTF timings, which
329 		 * could, in theory, be present.
330 		 */
331 		vesagtf_mode(x, y, f, vmp);
332 	}
333 	return 1;
334 }
335 
336 static int
337 edid_det_timing(uint8_t *data, struct videomode *vmp)
338 {
339 	unsigned	hactive, hblank, hsyncwid, hsyncoff;
340 	unsigned	vactive, vblank, vsyncwid, vsyncoff;
341 	uint8_t		flags;
342 
343 	flags = EDID_DET_TIMING_FLAGS(data);
344 
345 	/* we don't support stereo modes (for now) */
346 	if (flags & (EDID_DET_TIMING_FLAG_STEREO |
347 		EDID_DET_TIMING_FLAG_STEREO1))
348 		return 0;
349 
350 	vmp->dot_clock = EDID_DET_TIMING_DOT_CLOCK(data) / 1000;
351 
352 	hactive = EDID_DET_TIMING_HACTIVE(data);
353 	hblank = EDID_DET_TIMING_HBLANK(data);
354 	hsyncwid = EDID_DET_TIMING_HSYNC_WIDTH(data);
355 	hsyncoff = EDID_DET_TIMING_HSYNC_OFFSET(data);
356 
357 	vactive = EDID_DET_TIMING_VACTIVE(data);
358 	vblank = EDID_DET_TIMING_VBLANK(data);
359 	vsyncwid = EDID_DET_TIMING_VSYNC_WIDTH(data);
360 	vsyncoff = EDID_DET_TIMING_VSYNC_OFFSET(data);
361 
362 	/* XXX: I'm not doing anything with the borders, should I? */
363 
364 	vmp->hdisplay = hactive;
365 	vmp->htotal = hactive + hblank;
366 	vmp->hsync_start = hactive + hsyncoff;
367 	vmp->hsync_end = vmp->hsync_start + hsyncwid;
368 
369 	vmp->vdisplay = vactive;
370 	vmp->vtotal = vactive + vblank;
371 	vmp->vsync_start = vactive + vsyncoff;
372 	vmp->vsync_end = vmp->vsync_start + vsyncwid;
373 
374 	vmp->flags = 0;
375 
376 	if (flags & EDID_DET_TIMING_FLAG_INTERLACE)
377 		vmp->flags |= VID_INTERLACE;
378 	if (flags & EDID_DET_TIMING_FLAG_HSYNC_POSITIVE)
379 		vmp->flags |= VID_PHSYNC;
380 	else
381 		vmp->flags |= VID_NHSYNC;
382 
383 	if (flags & EDID_DET_TIMING_FLAG_VSYNC_POSITIVE)
384 		vmp->flags |= VID_PVSYNC;
385 	else
386 		vmp->flags |= VID_NVSYNC;
387 
388 	return 1;
389 }
390 
391 static void
392 edid_block(struct edid_info *edid, uint8_t *data)
393 {
394 	int			i;
395 	struct videomode	mode;
396 
397 	if (EDID_BLOCK_IS_DET_TIMING(data)) {
398 		if (edid_det_timing(data, &mode)) {
399 			edid->edid_modes[edid->edid_nmodes] = mode;
400 			if (edid->edid_preferred_mode == NULL) {
401 				edid->edid_preferred_mode =
402 				    &edid->edid_modes[edid->edid_nmodes];
403 			}
404 			edid->edid_nmodes++;
405 		}
406 		return;
407 	}
408 
409 	switch (EDID_BLOCK_TYPE(data)) {
410 	case EDID_DESC_BLOCK_TYPE_SERIAL:
411 		memcpy(edid->edid_serial,
412 		    data + EDID_DESC_ASCII_DATA_OFFSET,
413 		    EDID_DESC_ASCII_DATA_LEN);
414 		edid->edid_serial[sizeof (edid->edid_serial) - 1] = 0;
415 		break;
416 
417 	case EDID_DESC_BLOCK_TYPE_ASCII:
418 		memcpy(edid->edid_comment,
419 		    data + EDID_DESC_ASCII_DATA_OFFSET,
420 		    EDID_DESC_ASCII_DATA_LEN);
421 		edid->edid_comment[sizeof (edid->edid_comment) - 1] = 0;
422 		break;
423 
424 	case EDID_DESC_BLOCK_TYPE_RANGE:
425 		edid->edid_have_range = 1;
426 		edid->edid_range.er_min_vfreq =
427 		    EDID_DESC_RANGE_MIN_VFREQ(data);
428 		edid->edid_range.er_max_vfreq =
429 		    EDID_DESC_RANGE_MAX_VFREQ(data);
430 		edid->edid_range.er_min_hfreq =
431 		    EDID_DESC_RANGE_MIN_HFREQ(data);
432 		edid->edid_range.er_max_hfreq =
433 		    EDID_DESC_RANGE_MAX_HFREQ(data);
434 		edid->edid_range.er_max_clock =
435 		    EDID_DESC_RANGE_MAX_CLOCK(data);
436 		if (EDID_DESC_RANGE_HAVE_GTF2(data)) {
437 			edid->edid_range.er_have_gtf2 = 1;
438 			edid->edid_range.er_gtf2_hfreq =
439 			    EDID_DESC_RANGE_GTF2_HFREQ(data);
440 			edid->edid_range.er_gtf2_c =
441 			    EDID_DESC_RANGE_GTF2_C(data);
442 			edid->edid_range.er_gtf2_m =
443 			    EDID_DESC_RANGE_GTF2_M(data);
444 			edid->edid_range.er_gtf2_j =
445 			    EDID_DESC_RANGE_GTF2_J(data);
446 			edid->edid_range.er_gtf2_k =
447 			    EDID_DESC_RANGE_GTF2_K(data);
448 		}
449 		break;
450 
451 	case EDID_DESC_BLOCK_TYPE_NAME:
452 		/* copy the product name into place */
453 		memcpy(edid->edid_productname,
454 		    data + EDID_DESC_ASCII_DATA_OFFSET,
455 		    EDID_DESC_ASCII_DATA_LEN);
456 		break;
457 
458 	case EDID_DESC_BLOCK_TYPE_STD_TIMING:
459 		data += EDID_DESC_STD_TIMING_START;
460 		for (i = 0; i < EDID_DESC_STD_TIMING_COUNT; i++) {
461 			if (edid_std_timing(data, &mode)) {
462 				edid->edid_modes[edid->edid_nmodes] = mode;
463 				edid->edid_nmodes++;
464 			}
465 			data += 2;
466 		}
467 		break;
468 
469 	case EDID_DESC_BLOCK_TYPE_COLOR_POINT:
470 		/* XXX: not implemented yet */
471 		break;
472 	}
473 }
474 
475 /*
476  * Gets EDID version in BCD, e.g. EDID v1.3  returned as 0x0103
477  */
478 int
479 edid_parse(uint8_t *data, struct edid_info *edid)
480 {
481 	uint16_t		manfid, estmodes;
482 	const struct videomode	*vmp;
483 	int			i;
484 	const char		*name;
485 	int max_dotclock = 0;
486 	int mhz;
487 
488 	if (edid_is_valid(data) != 0)
489 		return -1;
490 
491 	/* get product identification */
492 	manfid = EDID_VENDOR_ID(data);
493 	edid->edid_vendor[0] = EDID_MANFID_0(manfid);
494 	edid->edid_vendor[1] = EDID_MANFID_1(manfid);
495 	edid->edid_vendor[2] = EDID_MANFID_2(manfid);
496 	edid->edid_vendor[3] = 0;	/* null terminate for convenience */
497 
498 	edid->edid_product = data[EDID_OFFSET_PRODUCT_ID] +
499 	    (data[EDID_OFFSET_PRODUCT_ID + 1] << 8);
500 
501 	name = edid_findvendor(edid->edid_vendor);
502 	if (name != NULL) {
503 		snprintf(edid->edid_vendorname,
504 		    sizeof (edid->edid_vendorname), "%s", name);
505 	}
506 	edid->edid_vendorname[sizeof (edid->edid_vendorname) - 1] = 0;
507 
508 	name = edid_findproduct(edid->edid_vendor, edid->edid_product);
509 	if (name != NULL) {
510 		snprintf(edid->edid_productname,
511 		    sizeof (edid->edid_productname), "%s", name);
512 	}
513 	edid->edid_productname[sizeof (edid->edid_productname) - 1] = 0;
514 
515 	snprintf(edid->edid_serial, sizeof (edid->edid_serial), "%08x",
516 	    EDID_SERIAL_NUMBER(data));
517 
518 	edid->edid_week = EDID_WEEK(data);
519 	edid->edid_year = EDID_YEAR(data);
520 
521 	/* get edid revision */
522 	edid->edid_version = EDID_VERSION(data);
523 	edid->edid_revision = EDID_REVISION(data);
524 
525 	edid->edid_video_input = EDID_VIDEO_INPUT(data);
526 	edid->edid_max_hsize = EDID_MAX_HSIZE(data);
527 	edid->edid_max_vsize = EDID_MAX_VSIZE(data);
528 
529 	edid->edid_gamma = EDID_GAMMA(data);
530 	edid->edid_features = EDID_FEATURES(data);
531 
532 	edid->edid_chroma.ec_redx = EDID_CHROMA_REDX(data);
533 	edid->edid_chroma.ec_redy = EDID_CHROMA_REDX(data);
534 	edid->edid_chroma.ec_greenx = EDID_CHROMA_GREENX(data);
535 	edid->edid_chroma.ec_greeny = EDID_CHROMA_GREENY(data);
536 	edid->edid_chroma.ec_bluex = EDID_CHROMA_BLUEX(data);
537 	edid->edid_chroma.ec_bluey = EDID_CHROMA_BLUEY(data);
538 	edid->edid_chroma.ec_whitex = EDID_CHROMA_WHITEX(data);
539 	edid->edid_chroma.ec_whitey = EDID_CHROMA_WHITEY(data);
540 
541 	/* lookup established modes */
542 	edid->edid_nmodes = 0;
543 	edid->edid_preferred_mode = NULL;
544 	estmodes = EDID_EST_TIMING(data);
545 	for (i = 0; i < 16; i++) {
546 		if (estmodes & (1 << i)) {
547 			vmp = edid_mode_lookup_list(_edid_modes[i]);
548 			if (vmp != NULL) {
549 				edid->edid_modes[edid->edid_nmodes] = *vmp;
550 				edid->edid_nmodes++;
551 			}
552 #ifdef DIAGNOSTIC
553 			  else
554 				printf("no data for est. mode %s\n",
555 				    _edid_modes[i]);
556 #endif
557 		}
558 	}
559 
560 	/* do standard timing section */
561 	for (i = 0; i < EDID_STD_TIMING_COUNT; i++) {
562 		struct videomode	mode;
563 		if (edid_std_timing(data + EDID_OFFSET_STD_TIMING + i * 2,
564 			&mode)) {
565 			edid->edid_modes[edid->edid_nmodes] = mode;
566 			edid->edid_nmodes++;
567 		}
568 	}
569 
570 	/* do detailed timings and descriptors */
571 	for (i = 0; i < EDID_BLOCK_COUNT; i++) {
572 		edid_block(edid, data + EDID_OFFSET_DESC_BLOCK +
573 		    i * EDID_BLOCK_SIZE);
574 	}
575 
576 	edid_strchomp(edid->edid_vendorname);
577 	edid_strchomp(edid->edid_productname);
578 	edid_strchomp(edid->edid_serial);
579 	edid_strchomp(edid->edid_comment);
580 
581 	/*
582 	 * XXX
583 	 * some monitors lie about their maximum supported dot clock
584 	 * by claiming to support modes which need a higher dot clock
585 	 * than the stated maximum.
586 	 * For sanity's sake we bump it to the highest dot clock we find
587 	 * in the list of supported modes
588 	 */
589 	for (i = 0; i < edid->edid_nmodes; i++)
590 		if (edid->edid_modes[i].dot_clock > max_dotclock)
591 			max_dotclock = edid->edid_modes[i].dot_clock;
592 
593 	aprint_verbose("max_dotclock according to supported modes: %d\n",
594 	    max_dotclock);
595 
596 	mhz = (max_dotclock + 999) / 1000;
597 
598 	if (edid->edid_have_range) {
599 
600 		if (mhz > edid->edid_range.er_max_clock)
601 			edid->edid_range.er_max_clock = mhz;
602 	} else
603 		edid->edid_range.er_max_clock = mhz;
604 
605 	return 0;
606 }
607 
608