xref: /linux/drivers/gpu/drm/drm_edid.c (revision f19900b2e608b604777a74d6d711bbf744657756)
1 /*
2  * Copyright (c) 2006 Luc Verhaegen (quirks list)
3  * Copyright (c) 2007-2008 Intel Corporation
4  *   Jesse Barnes <jesse.barnes@intel.com>
5  *
6  * DDC probing routines (drm_ddc_read & drm_do_probe_ddc_edid) originally from
7  * FB layer.
8  *   Copyright (C) 2006 Dennis Munsie <dmunsie@cecropia.com>
9  *
10  * Permission is hereby granted, free of charge, to any person obtaining a
11  * copy of this software and associated documentation files (the "Software"),
12  * to deal in the Software without restriction, including without limitation
13  * the rights to use, copy, modify, merge, publish, distribute, sub license,
14  * and/or sell copies of the Software, and to permit persons to whom the
15  * Software is furnished to do so, subject to the following conditions:
16  *
17  * The above copyright notice and this permission notice (including the
18  * next paragraph) shall be included in all copies or substantial portions
19  * of the Software.
20  *
21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
22  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
23  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
24  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
25  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
26  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
27  * DEALINGS IN THE SOFTWARE.
28  */
29 #include <linux/kernel.h>
30 #include <linux/i2c.h>
31 #include <linux/i2c-algo-bit.h>
32 #include "drmP.h"
33 #include "drm_edid.h"
34 
35 /*
36  * TODO:
37  *   - support EDID 1.4 (incl. CE blocks)
38  */
39 
40 /*
41  * EDID blocks out in the wild have a variety of bugs, try to collect
42  * them here (note that userspace may work around broken monitors first,
43  * but fixes should make their way here so that the kernel "just works"
44  * on as many displays as possible).
45  */
46 
47 /* First detailed mode wrong, use largest 60Hz mode */
48 #define EDID_QUIRK_PREFER_LARGE_60		(1 << 0)
49 /* Reported 135MHz pixel clock is too high, needs adjustment */
50 #define EDID_QUIRK_135_CLOCK_TOO_HIGH		(1 << 1)
51 /* Prefer the largest mode at 75 Hz */
52 #define EDID_QUIRK_PREFER_LARGE_75		(1 << 2)
53 /* Detail timing is in cm not mm */
54 #define EDID_QUIRK_DETAILED_IN_CM		(1 << 3)
55 /* Detailed timing descriptors have bogus size values, so just take the
56  * maximum size and use that.
57  */
58 #define EDID_QUIRK_DETAILED_USE_MAXIMUM_SIZE	(1 << 4)
59 /* Monitor forgot to set the first detailed is preferred bit. */
60 #define EDID_QUIRK_FIRST_DETAILED_PREFERRED	(1 << 5)
61 /* use +hsync +vsync for detailed mode */
62 #define EDID_QUIRK_DETAILED_SYNC_PP		(1 << 6)
63 
64 static struct edid_quirk {
65 	char *vendor;
66 	int product_id;
67 	u32 quirks;
68 } edid_quirk_list[] = {
69 	/* Acer AL1706 */
70 	{ "ACR", 44358, EDID_QUIRK_PREFER_LARGE_60 },
71 	/* Acer F51 */
72 	{ "API", 0x7602, EDID_QUIRK_PREFER_LARGE_60 },
73 	/* Unknown Acer */
74 	{ "ACR", 2423, EDID_QUIRK_FIRST_DETAILED_PREFERRED },
75 
76 	/* Belinea 10 15 55 */
77 	{ "MAX", 1516, EDID_QUIRK_PREFER_LARGE_60 },
78 	{ "MAX", 0x77e, EDID_QUIRK_PREFER_LARGE_60 },
79 
80 	/* Envision Peripherals, Inc. EN-7100e */
81 	{ "EPI", 59264, EDID_QUIRK_135_CLOCK_TOO_HIGH },
82 
83 	/* Funai Electronics PM36B */
84 	{ "FCM", 13600, EDID_QUIRK_PREFER_LARGE_75 |
85 	  EDID_QUIRK_DETAILED_IN_CM },
86 
87 	/* LG Philips LCD LP154W01-A5 */
88 	{ "LPL", 0, EDID_QUIRK_DETAILED_USE_MAXIMUM_SIZE },
89 	{ "LPL", 0x2a00, EDID_QUIRK_DETAILED_USE_MAXIMUM_SIZE },
90 
91 	/* Philips 107p5 CRT */
92 	{ "PHL", 57364, EDID_QUIRK_FIRST_DETAILED_PREFERRED },
93 
94 	/* Proview AY765C */
95 	{ "PTS", 765, EDID_QUIRK_FIRST_DETAILED_PREFERRED },
96 
97 	/* Samsung SyncMaster 205BW.  Note: irony */
98 	{ "SAM", 541, EDID_QUIRK_DETAILED_SYNC_PP },
99 	/* Samsung SyncMaster 22[5-6]BW */
100 	{ "SAM", 596, EDID_QUIRK_PREFER_LARGE_60 },
101 	{ "SAM", 638, EDID_QUIRK_PREFER_LARGE_60 },
102 };
103 
104 
105 /* Valid EDID header has these bytes */
106 static u8 edid_header[] = { 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00 };
107 
108 /**
109  * edid_is_valid - sanity check EDID data
110  * @edid: EDID data
111  *
112  * Sanity check the EDID block by looking at the header, the version number
113  * and the checksum.  Return 0 if the EDID doesn't check out, or 1 if it's
114  * valid.
115  */
116 static bool edid_is_valid(struct edid *edid)
117 {
118 	int i;
119 	u8 csum = 0;
120 	u8 *raw_edid = (u8 *)edid;
121 
122 	if (memcmp(edid->header, edid_header, sizeof(edid_header)))
123 		goto bad;
124 	if (edid->version != 1) {
125 		DRM_ERROR("EDID has major version %d, instead of 1\n", edid->version);
126 		goto bad;
127 	}
128 	if (edid->revision > 4)
129 		DRM_DEBUG("EDID minor > 4, assuming backward compatibility\n");
130 
131 	for (i = 0; i < EDID_LENGTH; i++)
132 		csum += raw_edid[i];
133 	if (csum) {
134 		DRM_ERROR("EDID checksum is invalid, remainder is %d\n", csum);
135 		goto bad;
136 	}
137 
138 	return 1;
139 
140 bad:
141 	if (raw_edid) {
142 		DRM_ERROR("Raw EDID:\n");
143 		print_hex_dump_bytes(KERN_ERR, DUMP_PREFIX_NONE, raw_edid, EDID_LENGTH);
144 		printk("\n");
145 	}
146 	return 0;
147 }
148 
149 /**
150  * edid_vendor - match a string against EDID's obfuscated vendor field
151  * @edid: EDID to match
152  * @vendor: vendor string
153  *
154  * Returns true if @vendor is in @edid, false otherwise
155  */
156 static bool edid_vendor(struct edid *edid, char *vendor)
157 {
158 	char edid_vendor[3];
159 
160 	edid_vendor[0] = ((edid->mfg_id[0] & 0x7c) >> 2) + '@';
161 	edid_vendor[1] = (((edid->mfg_id[0] & 0x3) << 3) |
162 			  ((edid->mfg_id[1] & 0xe0) >> 5)) + '@';
163 	edid_vendor[2] = (edid->mfg_id[1] & 0x1f) + '@';
164 
165 	return !strncmp(edid_vendor, vendor, 3);
166 }
167 
168 /**
169  * edid_get_quirks - return quirk flags for a given EDID
170  * @edid: EDID to process
171  *
172  * This tells subsequent routines what fixes they need to apply.
173  */
174 static u32 edid_get_quirks(struct edid *edid)
175 {
176 	struct edid_quirk *quirk;
177 	int i;
178 
179 	for (i = 0; i < ARRAY_SIZE(edid_quirk_list); i++) {
180 		quirk = &edid_quirk_list[i];
181 
182 		if (edid_vendor(edid, quirk->vendor) &&
183 		    (EDID_PRODUCT_ID(edid) == quirk->product_id))
184 			return quirk->quirks;
185 	}
186 
187 	return 0;
188 }
189 
190 #define MODE_SIZE(m) ((m)->hdisplay * (m)->vdisplay)
191 #define MODE_REFRESH_DIFF(m,r) (abs((m)->vrefresh - target_refresh))
192 
193 
194 /**
195  * edid_fixup_preferred - set preferred modes based on quirk list
196  * @connector: has mode list to fix up
197  * @quirks: quirks list
198  *
199  * Walk the mode list for @connector, clearing the preferred status
200  * on existing modes and setting it anew for the right mode ala @quirks.
201  */
202 static void edid_fixup_preferred(struct drm_connector *connector,
203 				 u32 quirks)
204 {
205 	struct drm_display_mode *t, *cur_mode, *preferred_mode;
206 	int target_refresh = 0;
207 
208 	if (list_empty(&connector->probed_modes))
209 		return;
210 
211 	if (quirks & EDID_QUIRK_PREFER_LARGE_60)
212 		target_refresh = 60;
213 	if (quirks & EDID_QUIRK_PREFER_LARGE_75)
214 		target_refresh = 75;
215 
216 	preferred_mode = list_first_entry(&connector->probed_modes,
217 					  struct drm_display_mode, head);
218 
219 	list_for_each_entry_safe(cur_mode, t, &connector->probed_modes, head) {
220 		cur_mode->type &= ~DRM_MODE_TYPE_PREFERRED;
221 
222 		if (cur_mode == preferred_mode)
223 			continue;
224 
225 		/* Largest mode is preferred */
226 		if (MODE_SIZE(cur_mode) > MODE_SIZE(preferred_mode))
227 			preferred_mode = cur_mode;
228 
229 		/* At a given size, try to get closest to target refresh */
230 		if ((MODE_SIZE(cur_mode) == MODE_SIZE(preferred_mode)) &&
231 		    MODE_REFRESH_DIFF(cur_mode, target_refresh) <
232 		    MODE_REFRESH_DIFF(preferred_mode, target_refresh)) {
233 			preferred_mode = cur_mode;
234 		}
235 	}
236 
237 	preferred_mode->type |= DRM_MODE_TYPE_PREFERRED;
238 }
239 
240 /**
241  * drm_mode_std - convert standard mode info (width, height, refresh) into mode
242  * @t: standard timing params
243  *
244  * Take the standard timing params (in this case width, aspect, and refresh)
245  * and convert them into a real mode using CVT.
246  *
247  * Punts for now, but should eventually use the FB layer's CVT based mode
248  * generation code.
249  */
250 struct drm_display_mode *drm_mode_std(struct drm_device *dev,
251 				      struct std_timing *t)
252 {
253 	struct drm_display_mode *mode;
254 	int hsize = t->hsize * 8 + 248, vsize;
255 
256 	mode = drm_mode_create(dev);
257 	if (!mode)
258 		return NULL;
259 
260 	if (t->aspect_ratio == 0)
261 		vsize = (hsize * 10) / 16;
262 	else if (t->aspect_ratio == 1)
263 		vsize = (hsize * 3) / 4;
264 	else if (t->aspect_ratio == 2)
265 		vsize = (hsize * 4) / 5;
266 	else
267 		vsize = (hsize * 9) / 16;
268 
269 	drm_mode_set_name(mode);
270 
271 	return mode;
272 }
273 
274 /**
275  * drm_mode_detailed - create a new mode from an EDID detailed timing section
276  * @dev: DRM device (needed to create new mode)
277  * @edid: EDID block
278  * @timing: EDID detailed timing info
279  * @quirks: quirks to apply
280  *
281  * An EDID detailed timing block contains enough info for us to create and
282  * return a new struct drm_display_mode.
283  */
284 static struct drm_display_mode *drm_mode_detailed(struct drm_device *dev,
285 						  struct edid *edid,
286 						  struct detailed_timing *timing,
287 						  u32 quirks)
288 {
289 	struct drm_display_mode *mode;
290 	struct detailed_pixel_timing *pt = &timing->data.pixel_data;
291 
292 	if (pt->stereo) {
293 		printk(KERN_WARNING "stereo mode not supported\n");
294 		return NULL;
295 	}
296 	if (!pt->separate_sync) {
297 		printk(KERN_WARNING "integrated sync not supported\n");
298 		return NULL;
299 	}
300 
301 	mode = drm_mode_create(dev);
302 	if (!mode)
303 		return NULL;
304 
305 	mode->type = DRM_MODE_TYPE_DRIVER;
306 
307 	if (quirks & EDID_QUIRK_135_CLOCK_TOO_HIGH)
308 		timing->pixel_clock = 1088;
309 
310 	mode->clock = timing->pixel_clock * 10;
311 
312 	mode->hdisplay = (pt->hactive_hi << 8) | pt->hactive_lo;
313 	mode->hsync_start = mode->hdisplay + ((pt->hsync_offset_hi << 8) |
314 					      pt->hsync_offset_lo);
315 	mode->hsync_end = mode->hsync_start +
316 		((pt->hsync_pulse_width_hi << 8) |
317 		 pt->hsync_pulse_width_lo);
318 	mode->htotal = mode->hdisplay + ((pt->hblank_hi << 8) | pt->hblank_lo);
319 
320 	mode->vdisplay = (pt->vactive_hi << 8) | pt->vactive_lo;
321 	mode->vsync_start = mode->vdisplay + ((pt->vsync_offset_hi << 4) |
322 					      pt->vsync_offset_lo);
323 	mode->vsync_end = mode->vsync_start +
324 		((pt->vsync_pulse_width_hi << 4) |
325 		 pt->vsync_pulse_width_lo);
326 	mode->vtotal = mode->vdisplay + ((pt->vblank_hi << 8) | pt->vblank_lo);
327 
328 	drm_mode_set_name(mode);
329 
330 	if (pt->interlaced)
331 		mode->flags |= DRM_MODE_FLAG_INTERLACE;
332 
333 	if (quirks & EDID_QUIRK_DETAILED_SYNC_PP) {
334 		pt->hsync_positive = 1;
335 		pt->vsync_positive = 1;
336 	}
337 
338 	mode->flags |= pt->hsync_positive ? DRM_MODE_FLAG_PHSYNC : DRM_MODE_FLAG_NHSYNC;
339 	mode->flags |= pt->vsync_positive ? DRM_MODE_FLAG_PVSYNC : DRM_MODE_FLAG_NVSYNC;
340 
341 	mode->width_mm = pt->width_mm_lo | (pt->width_mm_hi << 8);
342 	mode->height_mm = pt->height_mm_lo | (pt->height_mm_hi << 8);
343 
344 	if (quirks & EDID_QUIRK_DETAILED_IN_CM) {
345 		mode->width_mm *= 10;
346 		mode->height_mm *= 10;
347 	}
348 
349 	if (quirks & EDID_QUIRK_DETAILED_USE_MAXIMUM_SIZE) {
350 		mode->width_mm = edid->width_cm * 10;
351 		mode->height_mm = edid->height_cm * 10;
352 	}
353 
354 	return mode;
355 }
356 
357 /*
358  * Detailed mode info for the EDID "established modes" data to use.
359  */
360 static struct drm_display_mode edid_est_modes[] = {
361 	{ DRM_MODE("800x600", DRM_MODE_TYPE_DRIVER, 40000, 800, 840,
362 		   968, 1056, 0, 600, 601, 605, 628, 0,
363 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 800x600@60Hz */
364 	{ DRM_MODE("800x600", DRM_MODE_TYPE_DRIVER, 36000, 800, 824,
365 		   896, 1024, 0, 600, 601, 603,  625, 0,
366 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 800x600@56Hz */
367 	{ DRM_MODE("640x480", DRM_MODE_TYPE_DRIVER, 31500, 640, 656,
368 		   720, 840, 0, 480, 481, 484, 500, 0,
369 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 640x480@75Hz */
370 	{ DRM_MODE("640x480", DRM_MODE_TYPE_DRIVER, 31500, 640, 664,
371 		   704,  832, 0, 480, 489, 491, 520, 0,
372 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 640x480@72Hz */
373 	{ DRM_MODE("640x480", DRM_MODE_TYPE_DRIVER, 30240, 640, 704,
374 		   768,  864, 0, 480, 483, 486, 525, 0,
375 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 640x480@67Hz */
376 	{ DRM_MODE("640x480", DRM_MODE_TYPE_DRIVER, 25200, 640, 656,
377 		   752, 800, 0, 480, 490, 492, 525, 0,
378 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 640x480@60Hz */
379 	{ DRM_MODE("720x400", DRM_MODE_TYPE_DRIVER, 35500, 720, 738,
380 		   846, 900, 0, 400, 421, 423,  449, 0,
381 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 720x400@88Hz */
382 	{ DRM_MODE("720x400", DRM_MODE_TYPE_DRIVER, 28320, 720, 738,
383 		   846,  900, 0, 400, 412, 414, 449, 0,
384 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 720x400@70Hz */
385 	{ DRM_MODE("1280x1024", DRM_MODE_TYPE_DRIVER, 135000, 1280, 1296,
386 		   1440, 1688, 0, 1024, 1025, 1028, 1066, 0,
387 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 1280x1024@75Hz */
388 	{ DRM_MODE("1024x768", DRM_MODE_TYPE_DRIVER, 78800, 1024, 1040,
389 		   1136, 1312, 0,  768, 769, 772, 800, 0,
390 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 1024x768@75Hz */
391 	{ DRM_MODE("1024x768", DRM_MODE_TYPE_DRIVER, 75000, 1024, 1048,
392 		   1184, 1328, 0,  768, 771, 777, 806, 0,
393 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 1024x768@70Hz */
394 	{ DRM_MODE("1024x768", DRM_MODE_TYPE_DRIVER, 65000, 1024, 1048,
395 		   1184, 1344, 0,  768, 771, 777, 806, 0,
396 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 1024x768@60Hz */
397 	{ DRM_MODE("1024x768", DRM_MODE_TYPE_DRIVER,44900, 1024, 1032,
398 		   1208, 1264, 0, 768, 768, 776, 817, 0,
399 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC | DRM_MODE_FLAG_INTERLACE) }, /* 1024x768@43Hz */
400 	{ DRM_MODE("832x624", DRM_MODE_TYPE_DRIVER, 57284, 832, 864,
401 		   928, 1152, 0, 624, 625, 628, 667, 0,
402 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 832x624@75Hz */
403 	{ DRM_MODE("800x600", DRM_MODE_TYPE_DRIVER, 49500, 800, 816,
404 		   896, 1056, 0, 600, 601, 604,  625, 0,
405 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 800x600@75Hz */
406 	{ DRM_MODE("800x600", DRM_MODE_TYPE_DRIVER, 50000, 800, 856,
407 		   976, 1040, 0, 600, 637, 643, 666, 0,
408 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 800x600@72Hz */
409 	{ DRM_MODE("1152x864", DRM_MODE_TYPE_DRIVER, 108000, 1152, 1216,
410 		   1344, 1600, 0,  864, 865, 868, 900, 0,
411 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 1152x864@75Hz */
412 };
413 
414 #define EDID_EST_TIMINGS 16
415 #define EDID_STD_TIMINGS 8
416 #define EDID_DETAILED_TIMINGS 4
417 
418 /**
419  * add_established_modes - get est. modes from EDID and add them
420  * @edid: EDID block to scan
421  *
422  * Each EDID block contains a bitmap of the supported "established modes" list
423  * (defined above).  Tease them out and add them to the global modes list.
424  */
425 static int add_established_modes(struct drm_connector *connector, struct edid *edid)
426 {
427 	struct drm_device *dev = connector->dev;
428 	unsigned long est_bits = edid->established_timings.t1 |
429 		(edid->established_timings.t2 << 8) |
430 		((edid->established_timings.mfg_rsvd & 0x80) << 9);
431 	int i, modes = 0;
432 
433 	for (i = 0; i <= EDID_EST_TIMINGS; i++)
434 		if (est_bits & (1<<i)) {
435 			struct drm_display_mode *newmode;
436 			newmode = drm_mode_duplicate(dev, &edid_est_modes[i]);
437 			if (newmode) {
438 				drm_mode_probed_add(connector, newmode);
439 				modes++;
440 			}
441 		}
442 
443 	return modes;
444 }
445 
446 /**
447  * add_standard_modes - get std. modes from EDID and add them
448  * @edid: EDID block to scan
449  *
450  * Standard modes can be calculated using the CVT standard.  Grab them from
451  * @edid, calculate them, and add them to the list.
452  */
453 static int add_standard_modes(struct drm_connector *connector, struct edid *edid)
454 {
455 	struct drm_device *dev = connector->dev;
456 	int i, modes = 0;
457 
458 	for (i = 0; i < EDID_STD_TIMINGS; i++) {
459 		struct std_timing *t = &edid->standard_timings[i];
460 		struct drm_display_mode *newmode;
461 
462 		/* If std timings bytes are 1, 1 it's empty */
463 		if (t->hsize == 1 && (t->aspect_ratio | t->vfreq) == 1)
464 			continue;
465 
466 		newmode = drm_mode_std(dev, &edid->standard_timings[i]);
467 		if (newmode) {
468 			drm_mode_probed_add(connector, newmode);
469 			modes++;
470 		}
471 	}
472 
473 	return modes;
474 }
475 
476 /**
477  * add_detailed_modes - get detailed mode info from EDID data
478  * @connector: attached connector
479  * @edid: EDID block to scan
480  * @quirks: quirks to apply
481  *
482  * Some of the detailed timing sections may contain mode information.  Grab
483  * it and add it to the list.
484  */
485 static int add_detailed_info(struct drm_connector *connector,
486 			     struct edid *edid, u32 quirks)
487 {
488 	struct drm_device *dev = connector->dev;
489 	int i, j, modes = 0;
490 
491 	for (i = 0; i < EDID_DETAILED_TIMINGS; i++) {
492 		struct detailed_timing *timing = &edid->detailed_timings[i];
493 		struct detailed_non_pixel *data = &timing->data.other_data;
494 		struct drm_display_mode *newmode;
495 
496 		/* EDID up to and including 1.2 may put monitor info here */
497 		if (edid->version == 1 && edid->revision < 3)
498 			continue;
499 
500 		/* Detailed mode timing */
501 		if (timing->pixel_clock) {
502 			newmode = drm_mode_detailed(dev, edid, timing, quirks);
503 			if (!newmode)
504 				continue;
505 
506 			/* First detailed mode is preferred */
507 			if (i == 0 && edid->preferred_timing)
508 				newmode->type |= DRM_MODE_TYPE_PREFERRED;
509 			drm_mode_probed_add(connector, newmode);
510 
511 			modes++;
512 			continue;
513 		}
514 
515 		/* Other timing or info */
516 		switch (data->type) {
517 		case EDID_DETAIL_MONITOR_SERIAL:
518 			break;
519 		case EDID_DETAIL_MONITOR_STRING:
520 			break;
521 		case EDID_DETAIL_MONITOR_RANGE:
522 			/* Get monitor range data */
523 			break;
524 		case EDID_DETAIL_MONITOR_NAME:
525 			break;
526 		case EDID_DETAIL_MONITOR_CPDATA:
527 			break;
528 		case EDID_DETAIL_STD_MODES:
529 			/* Five modes per detailed section */
530 			for (j = 0; j < 5; i++) {
531 				struct std_timing *std;
532 				struct drm_display_mode *newmode;
533 
534 				std = &data->data.timings[j];
535 				newmode = drm_mode_std(dev, std);
536 				if (newmode) {
537 					drm_mode_probed_add(connector, newmode);
538 					modes++;
539 				}
540 			}
541 			break;
542 		default:
543 			break;
544 		}
545 	}
546 
547 	return modes;
548 }
549 
550 #define DDC_ADDR 0x50
551 /**
552  * Get EDID information via I2C.
553  *
554  * \param adapter : i2c device adaptor
555  * \param buf     : EDID data buffer to be filled
556  * \param len     : EDID data buffer length
557  * \return 0 on success or -1 on failure.
558  *
559  * Try to fetch EDID information by calling i2c driver function.
560  */
561 int drm_do_probe_ddc_edid(struct i2c_adapter *adapter,
562 			  unsigned char *buf, int len)
563 {
564 	unsigned char start = 0x0;
565 	struct i2c_msg msgs[] = {
566 		{
567 			.addr	= DDC_ADDR,
568 			.flags	= 0,
569 			.len	= 1,
570 			.buf	= &start,
571 		}, {
572 			.addr	= DDC_ADDR,
573 			.flags	= I2C_M_RD,
574 			.len	= len,
575 			.buf	= buf,
576 		}
577 	};
578 
579 	if (i2c_transfer(adapter, msgs, 2) == 2)
580 		return 0;
581 
582 	dev_info(&adapter->dev, "unable to read EDID block.\n");
583 	return -1;
584 }
585 EXPORT_SYMBOL(drm_do_probe_ddc_edid);
586 
587 /**
588  * Get EDID information.
589  *
590  * \param adapter : i2c device adaptor.
591  * \param buf     : EDID data buffer to be filled
592  * \param len     : EDID data buffer length
593  * \return 0 on success or -1 on failure.
594  *
595  * Initialize DDC, then fetch EDID information
596  * by calling drm_do_probe_ddc_edid function.
597  */
598 static int drm_ddc_read(struct i2c_adapter *adapter,
599 			unsigned char *buf, int len)
600 {
601 	struct i2c_algo_bit_data *algo_data = adapter->algo_data;
602 	int i, j;
603 	int ret = -1;
604 
605 	algo_data->setscl(algo_data->data, 1);
606 
607 	for (i = 0; i < 1; i++) {
608 		/* For some old monitors we need the
609 		 * following process to initialize/stop DDC
610 		 */
611 		algo_data->setsda(algo_data->data, 1);
612 		msleep(13);
613 
614 		algo_data->setscl(algo_data->data, 1);
615 		for (j = 0; j < 5; j++) {
616 			msleep(10);
617 			if (algo_data->getscl(algo_data->data))
618 				break;
619 		}
620 		if (j == 5)
621 			continue;
622 
623 		algo_data->setsda(algo_data->data, 0);
624 		msleep(15);
625 		algo_data->setscl(algo_data->data, 0);
626 		msleep(15);
627 		algo_data->setsda(algo_data->data, 1);
628 		msleep(15);
629 
630 		/* Do the real work */
631 		ret = drm_do_probe_ddc_edid(adapter, buf, len);
632 		algo_data->setsda(algo_data->data, 0);
633 		algo_data->setscl(algo_data->data, 0);
634 		msleep(15);
635 
636 		algo_data->setscl(algo_data->data, 1);
637 		for (j = 0; j < 10; j++) {
638 			msleep(10);
639 			if (algo_data->getscl(algo_data->data))
640 				break;
641 		}
642 
643 		algo_data->setsda(algo_data->data, 1);
644 		msleep(15);
645 		algo_data->setscl(algo_data->data, 0);
646 		algo_data->setsda(algo_data->data, 0);
647 		if (ret == 0)
648 			break;
649 	}
650 	/* Release the DDC lines when done or the Apple Cinema HD display
651 	 * will switch off
652 	 */
653 	algo_data->setsda(algo_data->data, 1);
654 	algo_data->setscl(algo_data->data, 1);
655 
656 	return ret;
657 }
658 
659 static int drm_ddc_read_edid(struct drm_connector *connector,
660 			     struct i2c_adapter *adapter,
661 			     char *buf, int len)
662 {
663 	int ret;
664 
665 	ret = drm_ddc_read(adapter, buf, len);
666 	if (ret != 0) {
667 		dev_info(&connector->dev->pdev->dev, "%s: no EDID data\n",
668 			 drm_get_connector_name(connector));
669 		goto end;
670 	}
671 	if (!edid_is_valid((struct edid *)buf)) {
672 		dev_warn(&connector->dev->pdev->dev, "%s: EDID invalid.\n",
673 			 drm_get_connector_name(connector));
674 		ret = -1;
675 	}
676 end:
677 	return ret;
678 }
679 
680 #define MAX_EDID_EXT_NUM 4
681 /**
682  * drm_get_edid - get EDID data, if available
683  * @connector: connector we're probing
684  * @adapter: i2c adapter to use for DDC
685  *
686  * Poke the given connector's i2c channel to grab EDID data if possible.
687  *
688  * Return edid data or NULL if we couldn't find any.
689  */
690 struct edid *drm_get_edid(struct drm_connector *connector,
691 			  struct i2c_adapter *adapter)
692 {
693 	int ret;
694 	struct edid *edid;
695 
696 	edid = kmalloc(EDID_LENGTH * (MAX_EDID_EXT_NUM + 1),
697 		       GFP_KERNEL);
698 	if (edid == NULL) {
699 		dev_warn(&connector->dev->pdev->dev,
700 			 "Failed to allocate EDID\n");
701 		goto end;
702 	}
703 
704 	/* Read first EDID block */
705 	ret = drm_ddc_read_edid(connector, adapter,
706 				(unsigned char *)edid, EDID_LENGTH);
707 	if (ret != 0)
708 		goto clean_up;
709 
710 	/* There are EDID extensions to be read */
711 	if (edid->extensions != 0) {
712 		int edid_ext_num = edid->extensions;
713 
714 		if (edid_ext_num > MAX_EDID_EXT_NUM) {
715 			dev_warn(&connector->dev->pdev->dev,
716 				 "The number of extension(%d) is "
717 				 "over max (%d), actually read number (%d)\n",
718 				 edid_ext_num, MAX_EDID_EXT_NUM,
719 				 MAX_EDID_EXT_NUM);
720 			/* Reset EDID extension number to be read */
721 			edid_ext_num = MAX_EDID_EXT_NUM;
722 		}
723 		/* Read EDID including extensions too */
724 		ret = drm_ddc_read_edid(connector, adapter, (char *)edid,
725 					EDID_LENGTH * (edid_ext_num + 1));
726 		if (ret != 0)
727 			goto clean_up;
728 
729 	}
730 
731 	connector->display_info.raw_edid = (char *)edid;
732 	goto end;
733 
734 clean_up:
735 	kfree(edid);
736 	edid = NULL;
737 end:
738 	return edid;
739 
740 }
741 EXPORT_SYMBOL(drm_get_edid);
742 
743 #define HDMI_IDENTIFIER 0x000C03
744 #define VENDOR_BLOCK    0x03
745 /**
746  * drm_detect_hdmi_monitor - detect whether monitor is hdmi.
747  * @edid: monitor EDID information
748  *
749  * Parse the CEA extension according to CEA-861-B.
750  * Return true if HDMI, false if not or unknown.
751  */
752 bool drm_detect_hdmi_monitor(struct edid *edid)
753 {
754 	char *edid_ext = NULL;
755 	int i, hdmi_id, edid_ext_num;
756 	int start_offset, end_offset;
757 	bool is_hdmi = false;
758 
759 	/* No EDID or EDID extensions */
760 	if (edid == NULL || edid->extensions == 0)
761 		goto end;
762 
763 	/* Chose real EDID extension number */
764 	edid_ext_num = edid->extensions > MAX_EDID_EXT_NUM ?
765 		       MAX_EDID_EXT_NUM : edid->extensions;
766 
767 	/* Find CEA extension */
768 	for (i = 0; i < edid_ext_num; i++) {
769 		edid_ext = (char *)edid + EDID_LENGTH * (i + 1);
770 		/* This block is CEA extension */
771 		if (edid_ext[0] == 0x02)
772 			break;
773 	}
774 
775 	if (i == edid_ext_num)
776 		goto end;
777 
778 	/* Data block offset in CEA extension block */
779 	start_offset = 4;
780 	end_offset = edid_ext[2];
781 
782 	/*
783 	 * Because HDMI identifier is in Vendor Specific Block,
784 	 * search it from all data blocks of CEA extension.
785 	 */
786 	for (i = start_offset; i < end_offset;
787 		/* Increased by data block len */
788 		i += ((edid_ext[i] & 0x1f) + 1)) {
789 		/* Find vendor specific block */
790 		if ((edid_ext[i] >> 5) == VENDOR_BLOCK) {
791 			hdmi_id = edid_ext[i + 1] | (edid_ext[i + 2] << 8) |
792 				  edid_ext[i + 3] << 16;
793 			/* Find HDMI identifier */
794 			if (hdmi_id == HDMI_IDENTIFIER)
795 				is_hdmi = true;
796 			break;
797 		}
798 	}
799 
800 end:
801 	return is_hdmi;
802 }
803 EXPORT_SYMBOL(drm_detect_hdmi_monitor);
804 
805 /**
806  * drm_add_edid_modes - add modes from EDID data, if available
807  * @connector: connector we're probing
808  * @edid: edid data
809  *
810  * Add the specified modes to the connector's mode list.
811  *
812  * Return number of modes added or 0 if we couldn't find any.
813  */
814 int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid)
815 {
816 	int num_modes = 0;
817 	u32 quirks;
818 
819 	if (edid == NULL) {
820 		return 0;
821 	}
822 	if (!edid_is_valid(edid)) {
823 		dev_warn(&connector->dev->pdev->dev, "%s: EDID invalid.\n",
824 			 drm_get_connector_name(connector));
825 		return 0;
826 	}
827 
828 	quirks = edid_get_quirks(edid);
829 
830 	num_modes += add_established_modes(connector, edid);
831 	num_modes += add_standard_modes(connector, edid);
832 	num_modes += add_detailed_info(connector, edid, quirks);
833 
834 	if (quirks & (EDID_QUIRK_PREFER_LARGE_60 | EDID_QUIRK_PREFER_LARGE_75))
835 		edid_fixup_preferred(connector, quirks);
836 
837 	connector->display_info.serration_vsync = edid->serration_vsync;
838 	connector->display_info.sync_on_green = edid->sync_on_green;
839 	connector->display_info.composite_sync = edid->composite_sync;
840 	connector->display_info.separate_syncs = edid->separate_syncs;
841 	connector->display_info.blank_to_black = edid->blank_to_black;
842 	connector->display_info.video_level = edid->video_level;
843 	connector->display_info.digital = edid->digital;
844 	connector->display_info.width_mm = edid->width_cm * 10;
845 	connector->display_info.height_mm = edid->height_cm * 10;
846 	connector->display_info.gamma = edid->gamma;
847 	connector->display_info.gtf_supported = edid->default_gtf;
848 	connector->display_info.standard_color = edid->standard_color;
849 	connector->display_info.display_type = edid->display_type;
850 	connector->display_info.active_off_supported = edid->pm_active_off;
851 	connector->display_info.suspend_supported = edid->pm_suspend;
852 	connector->display_info.standby_supported = edid->pm_standby;
853 	connector->display_info.gamma = edid->gamma;
854 
855 	return num_modes;
856 }
857 EXPORT_SYMBOL(drm_add_edid_modes);
858