xref: /linux/drivers/gpu/drm/drm_edid.c (revision 5da50258584469ddfee6545feb4eb2252a8d7e7b)
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 	unsigned aspect_ratio = (t->vfreq_aspect & EDID_TIMING_ASPECT_MASK)
256 		>> EDID_TIMING_ASPECT_SHIFT;
257 
258 	mode = drm_mode_create(dev);
259 	if (!mode)
260 		return NULL;
261 
262 	if (aspect_ratio == 0)
263 		vsize = (hsize * 10) / 16;
264 	else if (aspect_ratio == 1)
265 		vsize = (hsize * 3) / 4;
266 	else if (aspect_ratio == 2)
267 		vsize = (hsize * 4) / 5;
268 	else
269 		vsize = (hsize * 9) / 16;
270 
271 	drm_mode_set_name(mode);
272 
273 	return mode;
274 }
275 
276 /**
277  * drm_mode_detailed - create a new mode from an EDID detailed timing section
278  * @dev: DRM device (needed to create new mode)
279  * @edid: EDID block
280  * @timing: EDID detailed timing info
281  * @quirks: quirks to apply
282  *
283  * An EDID detailed timing block contains enough info for us to create and
284  * return a new struct drm_display_mode.
285  */
286 static struct drm_display_mode *drm_mode_detailed(struct drm_device *dev,
287 						  struct edid *edid,
288 						  struct detailed_timing *timing,
289 						  u32 quirks)
290 {
291 	struct drm_display_mode *mode;
292 	struct detailed_pixel_timing *pt = &timing->data.pixel_data;
293 	unsigned hactive = (pt->hactive_hblank_hi & 0xf0) << 4 | pt->hactive_lo;
294 	unsigned vactive = (pt->vactive_vblank_hi & 0xf0) << 4 | pt->vactive_lo;
295 	unsigned hblank = (pt->hactive_hblank_hi & 0xf) << 8 | pt->hblank_lo;
296 	unsigned vblank = (pt->vactive_vblank_hi & 0xf) << 8 | pt->vblank_lo;
297 	unsigned hsync_offset = (pt->hsync_vsync_offset_pulse_width_hi & 0xc0) << 2 | pt->hsync_offset_lo;
298 	unsigned hsync_pulse_width = (pt->hsync_vsync_offset_pulse_width_hi & 0x30) << 4 | pt->hsync_pulse_width_lo;
299 	unsigned vsync_offset = (pt->hsync_vsync_offset_pulse_width_hi & 0xc) >> 2 | pt->vsync_offset_pulse_width_lo >> 4;
300 	unsigned vsync_pulse_width = (pt->hsync_vsync_offset_pulse_width_hi & 0x3) << 4 | (pt->vsync_offset_pulse_width_lo & 0xf);
301 
302 	/* ignore tiny modes */
303 	if (hactive < 64 || vactive < 64)
304 		return NULL;
305 
306 	if (pt->misc & DRM_EDID_PT_STEREO) {
307 		printk(KERN_WARNING "stereo mode not supported\n");
308 		return NULL;
309 	}
310 	if (!(pt->misc & DRM_EDID_PT_SEPARATE_SYNC)) {
311 		printk(KERN_WARNING "integrated sync not supported\n");
312 		return NULL;
313 	}
314 
315 	mode = drm_mode_create(dev);
316 	if (!mode)
317 		return NULL;
318 
319 	mode->type = DRM_MODE_TYPE_DRIVER;
320 
321 	if (quirks & EDID_QUIRK_135_CLOCK_TOO_HIGH)
322 		timing->pixel_clock = cpu_to_le16(1088);
323 
324 	mode->clock = le16_to_cpu(timing->pixel_clock) * 10;
325 
326 	mode->hdisplay = hactive;
327 	mode->hsync_start = mode->hdisplay + hsync_offset;
328 	mode->hsync_end = mode->hsync_start + hsync_pulse_width;
329 	mode->htotal = mode->hdisplay + hblank;
330 
331 	mode->vdisplay = vactive;
332 	mode->vsync_start = mode->vdisplay + vsync_offset;
333 	mode->vsync_end = mode->vsync_start + vsync_pulse_width;
334 	mode->vtotal = mode->vdisplay + vblank;
335 
336 	drm_mode_set_name(mode);
337 
338 	if (pt->misc & DRM_EDID_PT_INTERLACED)
339 		mode->flags |= DRM_MODE_FLAG_INTERLACE;
340 
341 	if (quirks & EDID_QUIRK_DETAILED_SYNC_PP) {
342 		pt->misc |= DRM_EDID_PT_HSYNC_POSITIVE | DRM_EDID_PT_VSYNC_POSITIVE;
343 	}
344 
345 	mode->flags |= (pt->misc & DRM_EDID_PT_HSYNC_POSITIVE) ?
346 		DRM_MODE_FLAG_PHSYNC : DRM_MODE_FLAG_NHSYNC;
347 	mode->flags |= (pt->misc & DRM_EDID_PT_VSYNC_POSITIVE) ?
348 		DRM_MODE_FLAG_PVSYNC : DRM_MODE_FLAG_NVSYNC;
349 
350 	mode->width_mm = pt->width_mm_lo | (pt->width_height_mm_hi & 0xf0) << 4;
351 	mode->height_mm = pt->height_mm_lo | (pt->width_height_mm_hi & 0xf) << 8;
352 
353 	if (quirks & EDID_QUIRK_DETAILED_IN_CM) {
354 		mode->width_mm *= 10;
355 		mode->height_mm *= 10;
356 	}
357 
358 	if (quirks & EDID_QUIRK_DETAILED_USE_MAXIMUM_SIZE) {
359 		mode->width_mm = edid->width_cm * 10;
360 		mode->height_mm = edid->height_cm * 10;
361 	}
362 
363 	return mode;
364 }
365 
366 /*
367  * Detailed mode info for the EDID "established modes" data to use.
368  */
369 static struct drm_display_mode edid_est_modes[] = {
370 	{ DRM_MODE("800x600", DRM_MODE_TYPE_DRIVER, 40000, 800, 840,
371 		   968, 1056, 0, 600, 601, 605, 628, 0,
372 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 800x600@60Hz */
373 	{ DRM_MODE("800x600", DRM_MODE_TYPE_DRIVER, 36000, 800, 824,
374 		   896, 1024, 0, 600, 601, 603,  625, 0,
375 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 800x600@56Hz */
376 	{ DRM_MODE("640x480", DRM_MODE_TYPE_DRIVER, 31500, 640, 656,
377 		   720, 840, 0, 480, 481, 484, 500, 0,
378 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 640x480@75Hz */
379 	{ DRM_MODE("640x480", DRM_MODE_TYPE_DRIVER, 31500, 640, 664,
380 		   704,  832, 0, 480, 489, 491, 520, 0,
381 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 640x480@72Hz */
382 	{ DRM_MODE("640x480", DRM_MODE_TYPE_DRIVER, 30240, 640, 704,
383 		   768,  864, 0, 480, 483, 486, 525, 0,
384 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 640x480@67Hz */
385 	{ DRM_MODE("640x480", DRM_MODE_TYPE_DRIVER, 25200, 640, 656,
386 		   752, 800, 0, 480, 490, 492, 525, 0,
387 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 640x480@60Hz */
388 	{ DRM_MODE("720x400", DRM_MODE_TYPE_DRIVER, 35500, 720, 738,
389 		   846, 900, 0, 400, 421, 423,  449, 0,
390 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 720x400@88Hz */
391 	{ DRM_MODE("720x400", DRM_MODE_TYPE_DRIVER, 28320, 720, 738,
392 		   846,  900, 0, 400, 412, 414, 449, 0,
393 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 720x400@70Hz */
394 	{ DRM_MODE("1280x1024", DRM_MODE_TYPE_DRIVER, 135000, 1280, 1296,
395 		   1440, 1688, 0, 1024, 1025, 1028, 1066, 0,
396 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 1280x1024@75Hz */
397 	{ DRM_MODE("1024x768", DRM_MODE_TYPE_DRIVER, 78800, 1024, 1040,
398 		   1136, 1312, 0,  768, 769, 772, 800, 0,
399 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 1024x768@75Hz */
400 	{ DRM_MODE("1024x768", DRM_MODE_TYPE_DRIVER, 75000, 1024, 1048,
401 		   1184, 1328, 0,  768, 771, 777, 806, 0,
402 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 1024x768@70Hz */
403 	{ DRM_MODE("1024x768", DRM_MODE_TYPE_DRIVER, 65000, 1024, 1048,
404 		   1184, 1344, 0,  768, 771, 777, 806, 0,
405 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 1024x768@60Hz */
406 	{ DRM_MODE("1024x768", DRM_MODE_TYPE_DRIVER,44900, 1024, 1032,
407 		   1208, 1264, 0, 768, 768, 776, 817, 0,
408 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC | DRM_MODE_FLAG_INTERLACE) }, /* 1024x768@43Hz */
409 	{ DRM_MODE("832x624", DRM_MODE_TYPE_DRIVER, 57284, 832, 864,
410 		   928, 1152, 0, 624, 625, 628, 667, 0,
411 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 832x624@75Hz */
412 	{ DRM_MODE("800x600", DRM_MODE_TYPE_DRIVER, 49500, 800, 816,
413 		   896, 1056, 0, 600, 601, 604,  625, 0,
414 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 800x600@75Hz */
415 	{ DRM_MODE("800x600", DRM_MODE_TYPE_DRIVER, 50000, 800, 856,
416 		   976, 1040, 0, 600, 637, 643, 666, 0,
417 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 800x600@72Hz */
418 	{ DRM_MODE("1152x864", DRM_MODE_TYPE_DRIVER, 108000, 1152, 1216,
419 		   1344, 1600, 0,  864, 865, 868, 900, 0,
420 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 1152x864@75Hz */
421 };
422 
423 #define EDID_EST_TIMINGS 16
424 #define EDID_STD_TIMINGS 8
425 #define EDID_DETAILED_TIMINGS 4
426 
427 /**
428  * add_established_modes - get est. modes from EDID and add them
429  * @edid: EDID block to scan
430  *
431  * Each EDID block contains a bitmap of the supported "established modes" list
432  * (defined above).  Tease them out and add them to the global modes list.
433  */
434 static int add_established_modes(struct drm_connector *connector, struct edid *edid)
435 {
436 	struct drm_device *dev = connector->dev;
437 	unsigned long est_bits = edid->established_timings.t1 |
438 		(edid->established_timings.t2 << 8) |
439 		((edid->established_timings.mfg_rsvd & 0x80) << 9);
440 	int i, modes = 0;
441 
442 	for (i = 0; i <= EDID_EST_TIMINGS; i++)
443 		if (est_bits & (1<<i)) {
444 			struct drm_display_mode *newmode;
445 			newmode = drm_mode_duplicate(dev, &edid_est_modes[i]);
446 			if (newmode) {
447 				drm_mode_probed_add(connector, newmode);
448 				modes++;
449 			}
450 		}
451 
452 	return modes;
453 }
454 
455 /**
456  * add_standard_modes - get std. modes from EDID and add them
457  * @edid: EDID block to scan
458  *
459  * Standard modes can be calculated using the CVT standard.  Grab them from
460  * @edid, calculate them, and add them to the list.
461  */
462 static int add_standard_modes(struct drm_connector *connector, struct edid *edid)
463 {
464 	struct drm_device *dev = connector->dev;
465 	int i, modes = 0;
466 
467 	for (i = 0; i < EDID_STD_TIMINGS; i++) {
468 		struct std_timing *t = &edid->standard_timings[i];
469 		struct drm_display_mode *newmode;
470 
471 		/* If std timings bytes are 1, 1 it's empty */
472 		if (t->hsize == 1 && t->vfreq_aspect == 1)
473 			continue;
474 
475 		newmode = drm_mode_std(dev, &edid->standard_timings[i]);
476 		if (newmode) {
477 			drm_mode_probed_add(connector, newmode);
478 			modes++;
479 		}
480 	}
481 
482 	return modes;
483 }
484 
485 /**
486  * add_detailed_modes - get detailed mode info from EDID data
487  * @connector: attached connector
488  * @edid: EDID block to scan
489  * @quirks: quirks to apply
490  *
491  * Some of the detailed timing sections may contain mode information.  Grab
492  * it and add it to the list.
493  */
494 static int add_detailed_info(struct drm_connector *connector,
495 			     struct edid *edid, u32 quirks)
496 {
497 	struct drm_device *dev = connector->dev;
498 	int i, j, modes = 0;
499 
500 	for (i = 0; i < EDID_DETAILED_TIMINGS; i++) {
501 		struct detailed_timing *timing = &edid->detailed_timings[i];
502 		struct detailed_non_pixel *data = &timing->data.other_data;
503 		struct drm_display_mode *newmode;
504 
505 		/* EDID up to and including 1.2 may put monitor info here */
506 		if (edid->version == 1 && edid->revision < 3)
507 			continue;
508 
509 		/* Detailed mode timing */
510 		if (timing->pixel_clock) {
511 			newmode = drm_mode_detailed(dev, edid, timing, quirks);
512 			if (!newmode)
513 				continue;
514 
515 			/* First detailed mode is preferred */
516 			if (i == 0 && (edid->features & DRM_EDID_FEATURE_PREFERRED_TIMING))
517 				newmode->type |= DRM_MODE_TYPE_PREFERRED;
518 			drm_mode_probed_add(connector, newmode);
519 
520 			modes++;
521 			continue;
522 		}
523 
524 		/* Other timing or info */
525 		switch (data->type) {
526 		case EDID_DETAIL_MONITOR_SERIAL:
527 			break;
528 		case EDID_DETAIL_MONITOR_STRING:
529 			break;
530 		case EDID_DETAIL_MONITOR_RANGE:
531 			/* Get monitor range data */
532 			break;
533 		case EDID_DETAIL_MONITOR_NAME:
534 			break;
535 		case EDID_DETAIL_MONITOR_CPDATA:
536 			break;
537 		case EDID_DETAIL_STD_MODES:
538 			/* Five modes per detailed section */
539 			for (j = 0; j < 5; i++) {
540 				struct std_timing *std;
541 				struct drm_display_mode *newmode;
542 
543 				std = &data->data.timings[j];
544 				newmode = drm_mode_std(dev, std);
545 				if (newmode) {
546 					drm_mode_probed_add(connector, newmode);
547 					modes++;
548 				}
549 			}
550 			break;
551 		default:
552 			break;
553 		}
554 	}
555 
556 	return modes;
557 }
558 
559 #define DDC_ADDR 0x50
560 /**
561  * Get EDID information via I2C.
562  *
563  * \param adapter : i2c device adaptor
564  * \param buf     : EDID data buffer to be filled
565  * \param len     : EDID data buffer length
566  * \return 0 on success or -1 on failure.
567  *
568  * Try to fetch EDID information by calling i2c driver function.
569  */
570 int drm_do_probe_ddc_edid(struct i2c_adapter *adapter,
571 			  unsigned char *buf, int len)
572 {
573 	unsigned char start = 0x0;
574 	struct i2c_msg msgs[] = {
575 		{
576 			.addr	= DDC_ADDR,
577 			.flags	= 0,
578 			.len	= 1,
579 			.buf	= &start,
580 		}, {
581 			.addr	= DDC_ADDR,
582 			.flags	= I2C_M_RD,
583 			.len	= len,
584 			.buf	= buf,
585 		}
586 	};
587 
588 	if (i2c_transfer(adapter, msgs, 2) == 2)
589 		return 0;
590 
591 	dev_info(&adapter->dev, "unable to read EDID block.\n");
592 	return -1;
593 }
594 EXPORT_SYMBOL(drm_do_probe_ddc_edid);
595 
596 static int drm_ddc_read_edid(struct drm_connector *connector,
597 			     struct i2c_adapter *adapter,
598 			     char *buf, int len)
599 {
600 	int ret;
601 
602 	ret = drm_do_probe_ddc_edid(adapter, buf, len);
603 	if (ret != 0) {
604 		dev_info(&connector->dev->pdev->dev, "%s: no EDID data\n",
605 			 drm_get_connector_name(connector));
606 		goto end;
607 	}
608 	if (!edid_is_valid((struct edid *)buf)) {
609 		dev_warn(&connector->dev->pdev->dev, "%s: EDID invalid.\n",
610 			 drm_get_connector_name(connector));
611 		ret = -1;
612 	}
613 end:
614 	return ret;
615 }
616 
617 #define MAX_EDID_EXT_NUM 4
618 /**
619  * drm_get_edid - get EDID data, if available
620  * @connector: connector we're probing
621  * @adapter: i2c adapter to use for DDC
622  *
623  * Poke the given connector's i2c channel to grab EDID data if possible.
624  *
625  * Return edid data or NULL if we couldn't find any.
626  */
627 struct edid *drm_get_edid(struct drm_connector *connector,
628 			  struct i2c_adapter *adapter)
629 {
630 	int ret;
631 	struct edid *edid;
632 
633 	edid = kmalloc(EDID_LENGTH * (MAX_EDID_EXT_NUM + 1),
634 		       GFP_KERNEL);
635 	if (edid == NULL) {
636 		dev_warn(&connector->dev->pdev->dev,
637 			 "Failed to allocate EDID\n");
638 		goto end;
639 	}
640 
641 	/* Read first EDID block */
642 	ret = drm_ddc_read_edid(connector, adapter,
643 				(unsigned char *)edid, EDID_LENGTH);
644 	if (ret != 0)
645 		goto clean_up;
646 
647 	/* There are EDID extensions to be read */
648 	if (edid->extensions != 0) {
649 		int edid_ext_num = edid->extensions;
650 
651 		if (edid_ext_num > MAX_EDID_EXT_NUM) {
652 			dev_warn(&connector->dev->pdev->dev,
653 				 "The number of extension(%d) is "
654 				 "over max (%d), actually read number (%d)\n",
655 				 edid_ext_num, MAX_EDID_EXT_NUM,
656 				 MAX_EDID_EXT_NUM);
657 			/* Reset EDID extension number to be read */
658 			edid_ext_num = MAX_EDID_EXT_NUM;
659 		}
660 		/* Read EDID including extensions too */
661 		ret = drm_ddc_read_edid(connector, adapter, (char *)edid,
662 					EDID_LENGTH * (edid_ext_num + 1));
663 		if (ret != 0)
664 			goto clean_up;
665 
666 	}
667 
668 	connector->display_info.raw_edid = (char *)edid;
669 	goto end;
670 
671 clean_up:
672 	kfree(edid);
673 	edid = NULL;
674 end:
675 	return edid;
676 
677 }
678 EXPORT_SYMBOL(drm_get_edid);
679 
680 #define HDMI_IDENTIFIER 0x000C03
681 #define VENDOR_BLOCK    0x03
682 /**
683  * drm_detect_hdmi_monitor - detect whether monitor is hdmi.
684  * @edid: monitor EDID information
685  *
686  * Parse the CEA extension according to CEA-861-B.
687  * Return true if HDMI, false if not or unknown.
688  */
689 bool drm_detect_hdmi_monitor(struct edid *edid)
690 {
691 	char *edid_ext = NULL;
692 	int i, hdmi_id, edid_ext_num;
693 	int start_offset, end_offset;
694 	bool is_hdmi = false;
695 
696 	/* No EDID or EDID extensions */
697 	if (edid == NULL || edid->extensions == 0)
698 		goto end;
699 
700 	/* Chose real EDID extension number */
701 	edid_ext_num = edid->extensions > MAX_EDID_EXT_NUM ?
702 		       MAX_EDID_EXT_NUM : edid->extensions;
703 
704 	/* Find CEA extension */
705 	for (i = 0; i < edid_ext_num; i++) {
706 		edid_ext = (char *)edid + EDID_LENGTH * (i + 1);
707 		/* This block is CEA extension */
708 		if (edid_ext[0] == 0x02)
709 			break;
710 	}
711 
712 	if (i == edid_ext_num)
713 		goto end;
714 
715 	/* Data block offset in CEA extension block */
716 	start_offset = 4;
717 	end_offset = edid_ext[2];
718 
719 	/*
720 	 * Because HDMI identifier is in Vendor Specific Block,
721 	 * search it from all data blocks of CEA extension.
722 	 */
723 	for (i = start_offset; i < end_offset;
724 		/* Increased by data block len */
725 		i += ((edid_ext[i] & 0x1f) + 1)) {
726 		/* Find vendor specific block */
727 		if ((edid_ext[i] >> 5) == VENDOR_BLOCK) {
728 			hdmi_id = edid_ext[i + 1] | (edid_ext[i + 2] << 8) |
729 				  edid_ext[i + 3] << 16;
730 			/* Find HDMI identifier */
731 			if (hdmi_id == HDMI_IDENTIFIER)
732 				is_hdmi = true;
733 			break;
734 		}
735 	}
736 
737 end:
738 	return is_hdmi;
739 }
740 EXPORT_SYMBOL(drm_detect_hdmi_monitor);
741 
742 /**
743  * drm_add_edid_modes - add modes from EDID data, if available
744  * @connector: connector we're probing
745  * @edid: edid data
746  *
747  * Add the specified modes to the connector's mode list.
748  *
749  * Return number of modes added or 0 if we couldn't find any.
750  */
751 int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid)
752 {
753 	int num_modes = 0;
754 	u32 quirks;
755 
756 	if (edid == NULL) {
757 		return 0;
758 	}
759 	if (!edid_is_valid(edid)) {
760 		dev_warn(&connector->dev->pdev->dev, "%s: EDID invalid.\n",
761 			 drm_get_connector_name(connector));
762 		return 0;
763 	}
764 
765 	quirks = edid_get_quirks(edid);
766 
767 	num_modes += add_established_modes(connector, edid);
768 	num_modes += add_standard_modes(connector, edid);
769 	num_modes += add_detailed_info(connector, edid, quirks);
770 
771 	if (quirks & (EDID_QUIRK_PREFER_LARGE_60 | EDID_QUIRK_PREFER_LARGE_75))
772 		edid_fixup_preferred(connector, quirks);
773 
774 	connector->display_info.serration_vsync = (edid->input & DRM_EDID_INPUT_SERRATION_VSYNC) ? 1 : 0;
775 	connector->display_info.sync_on_green = (edid->input & DRM_EDID_INPUT_SYNC_ON_GREEN) ? 1 : 0;
776 	connector->display_info.composite_sync = (edid->input & DRM_EDID_INPUT_COMPOSITE_SYNC) ? 1 : 0;
777 	connector->display_info.separate_syncs = (edid->input & DRM_EDID_INPUT_SEPARATE_SYNCS) ? 1 : 0;
778 	connector->display_info.blank_to_black = (edid->input & DRM_EDID_INPUT_BLANK_TO_BLACK) ? 1 : 0;
779 	connector->display_info.video_level = (edid->input & DRM_EDID_INPUT_VIDEO_LEVEL) >> 5;
780 	connector->display_info.digital = (edid->input & DRM_EDID_INPUT_DIGITAL) ? 1 : 0;
781 	connector->display_info.width_mm = edid->width_cm * 10;
782 	connector->display_info.height_mm = edid->height_cm * 10;
783 	connector->display_info.gamma = edid->gamma;
784 	connector->display_info.gtf_supported = (edid->features & DRM_EDID_FEATURE_DEFAULT_GTF) ? 1 : 0;
785 	connector->display_info.standard_color = (edid->features & DRM_EDID_FEATURE_STANDARD_COLOR) ? 1 : 0;
786 	connector->display_info.display_type = (edid->features & DRM_EDID_FEATURE_DISPLAY_TYPE) >> 3;
787 	connector->display_info.active_off_supported = (edid->features & DRM_EDID_FEATURE_PM_ACTIVE_OFF) ? 1 : 0;
788 	connector->display_info.suspend_supported = (edid->features & DRM_EDID_FEATURE_PM_SUSPEND) ? 1 : 0;
789 	connector->display_info.standby_supported = (edid->features & DRM_EDID_FEATURE_PM_STANDBY) ? 1 : 0;
790 	connector->display_info.gamma = edid->gamma;
791 
792 	return num_modes;
793 }
794 EXPORT_SYMBOL(drm_add_edid_modes);
795