2 * Copyright (c) 2012 The Chromium OS Authors.
5 * Petr Stetiar <ynezz@true.cz>
7 * SPDX-License-Identifier: GPL-2.0+
9 * Contains stolen code from ddcprobe project which is:
10 * Copyright (C) Nalin Dahyabhai <bigfun@pobox.com>
17 #include <linux/ctype.h>
18 #include <linux/string.h>
20 int edid_check_info(struct edid1_info *edid_info)
22 if ((edid_info == NULL) || (edid_info->version == 0))
25 if (memcmp(edid_info->header, "\x0\xff\xff\xff\xff\xff\xff\x0", 8))
28 if (edid_info->version == 0xff && edid_info->revision == 0xff)
34 int edid_check_checksum(u8 *edid_block)
39 for (i = 0; i < 128; i++)
40 checksum += edid_block[i];
42 return (checksum == 0) ? 0 : -EINVAL;
45 int edid_get_ranges(struct edid1_info *edid, unsigned int *hmin,
46 unsigned int *hmax, unsigned int *vmin,
50 struct edid_monitor_descriptor *monitor;
52 *hmin = *hmax = *vmin = *vmax = 0;
53 if (edid_check_info(edid))
56 for (i = 0; i < ARRAY_SIZE(edid->monitor_details.descriptor); i++) {
57 monitor = &edid->monitor_details.descriptor[i];
58 if (monitor->type == EDID_MONITOR_DESCRIPTOR_RANGE) {
59 *hmin = monitor->data.range_data.horizontal_min;
60 *hmax = monitor->data.range_data.horizontal_max;
61 *vmin = monitor->data.range_data.vertical_min;
62 *vmax = monitor->data.range_data.vertical_max;
69 /* Set all parts of a timing entry to the same value */
70 static void set_entry(struct timing_entry *entry, u32 value)
78 * decode_timing() - Decoding an 18-byte detailed timing record
80 * @buf: Pointer to EDID detailed timing record
81 * @timing: Place to put timing
83 static void decode_timing(u8 *buf, struct display_timing *timing)
86 unsigned int ha, hbl, hso, hspw, hborder;
87 unsigned int va, vbl, vso, vspw, vborder;
88 struct edid_detailed_timing *t = (struct edid_detailed_timing *)buf;
90 /* Edid contains pixel clock in terms of 10KHz */
91 set_entry(&timing->pixelclock, (buf[0] + (buf[1] << 8)) * 10000);
92 x_mm = (buf[12] + ((buf[14] & 0xf0) << 4));
93 y_mm = (buf[13] + ((buf[14] & 0x0f) << 8));
94 ha = (buf[2] + ((buf[4] & 0xf0) << 4));
95 hbl = (buf[3] + ((buf[4] & 0x0f) << 8));
96 hso = (buf[8] + ((buf[11] & 0xc0) << 2));
97 hspw = (buf[9] + ((buf[11] & 0x30) << 4));
99 va = (buf[5] + ((buf[7] & 0xf0) << 4));
100 vbl = (buf[6] + ((buf[7] & 0x0f) << 8));
101 vso = ((buf[10] >> 4) + ((buf[11] & 0x0c) << 2));
102 vspw = ((buf[10] & 0x0f) + ((buf[11] & 0x03) << 4));
105 set_entry(&timing->hactive, ha);
106 set_entry(&timing->hfront_porch, hso);
107 set_entry(&timing->hback_porch, hbl - hso - hspw);
108 set_entry(&timing->hsync_len, hspw);
110 set_entry(&timing->vactive, va);
111 set_entry(&timing->vfront_porch, vso);
112 set_entry(&timing->vback_porch, vbl - vso - vspw);
113 set_entry(&timing->vsync_len, vspw);
116 if (EDID_DETAILED_TIMING_FLAG_HSYNC_POLARITY(*t))
117 timing->flags |= DISPLAY_FLAGS_HSYNC_HIGH;
119 timing->flags |= DISPLAY_FLAGS_HSYNC_LOW;
120 if (EDID_DETAILED_TIMING_FLAG_VSYNC_POLARITY(*t))
121 timing->flags |= DISPLAY_FLAGS_VSYNC_HIGH;
123 timing->flags |= DISPLAY_FLAGS_VSYNC_LOW;
125 if (EDID_DETAILED_TIMING_FLAG_INTERLACED(*t))
126 timing->flags = DISPLAY_FLAGS_INTERLACED;
128 debug("Detailed mode clock %u Hz, %d mm x %d mm\n"
129 " %04x %04x %04x %04x hborder %x\n"
130 " %04x %04x %04x %04x vborder %x\n",
131 timing->pixelclock.typ,
133 ha, ha + hso, ha + hso + hspw,
135 va, va + vso, va + vso + vspw,
140 * Check if HDMI vendor specific data block is present in CEA block
141 * @param info CEA extension block
142 * @return true if block is found
144 static bool cea_is_hdmi_vsdb_present(struct edid_cea861_info *info)
148 /* check for end of data block */
149 end = info->dtd_offset;
151 end = sizeof(info->data);
152 if (end < 4 || end > sizeof(info->data))
157 /* Look for vendor specific data block of appropriate size */
158 if ((EDID_CEA861_DB_TYPE(*info, i) == EDID_CEA861_DB_VENDOR) &&
159 (EDID_CEA861_DB_LEN(*info, i) >= 5)) {
160 u8 *db = &info->data[i + 1];
161 u32 oui = db[0] | (db[1] << 8) | (db[2] << 16);
163 if (oui == HDMI_IEEE_OUI)
166 i += EDID_CEA861_DB_LEN(*info, i) + 1;
172 int edid_get_timing(u8 *buf, int buf_size, struct display_timing *timing,
173 int *panel_bits_per_colourp)
175 struct edid1_info *edid = (struct edid1_info *)buf;
179 if (buf_size < sizeof(*edid) || edid_check_info(edid)) {
180 debug("%s: Invalid buffer\n", __func__);
184 if (!EDID1_INFO_FEATURE_PREFERRED_TIMING_MODE(*edid)) {
185 debug("%s: No preferred timing\n", __func__);
189 /* Look for detailed timing */
191 for (i = 0; i < 4; i++) {
192 struct edid_monitor_descriptor *desc;
194 desc = &edid->monitor_details.descriptor[i];
195 if (desc->zero_flag_1 != 0) {
196 decode_timing((u8 *)desc, timing);
204 if (!EDID1_INFO_VIDEO_INPUT_DIGITAL(*edid)) {
205 debug("%s: Not a digital display\n", __func__);
208 if (edid->version != 1 || edid->revision < 4) {
209 debug("%s: EDID version %d.%d does not have required info\n",
210 __func__, edid->version, edid->revision);
211 *panel_bits_per_colourp = -1;
213 *panel_bits_per_colourp =
214 ((edid->video_input_definition & 0x70) >> 3) + 4;
217 timing->hdmi_monitor = false;
218 if (edid->extension_flag && (buf_size >= EDID_EXT_SIZE)) {
219 struct edid_cea861_info *info =
220 (struct edid_cea861_info *)(buf + sizeof(*edid));
222 if (info->extension_tag == EDID_CEA861_EXTENSION_TAG)
223 timing->hdmi_monitor = cea_is_hdmi_vsdb_present(info);
230 * Snip the tailing whitespace/return of a string.
232 * @param string The string to be snipped
233 * @return the snipped string
235 static char *snip(char *string)
240 * This is always a 13 character buffer
241 * and it's not always terminated.
244 s = &string[strlen(string) - 1];
246 while (s >= string && (isspace(*s) || *s == '\n' || *s == '\r' ||
254 * Print an EDID monitor descriptor block
256 * @param monitor The EDID monitor descriptor block
257 * @have_timing Modifies to 1 if the desciptor contains timing info
259 static void edid_print_dtd(struct edid_monitor_descriptor *monitor,
260 unsigned int *have_timing)
262 unsigned char *bytes = (unsigned char *)monitor;
263 struct edid_detailed_timing *timing =
264 (struct edid_detailed_timing *)monitor;
266 if (bytes[0] == 0 && bytes[1] == 0) {
267 if (monitor->type == EDID_MONITOR_DESCRIPTOR_SERIAL)
268 printf("Monitor serial number: %s\n",
269 snip(monitor->data.string));
270 else if (monitor->type == EDID_MONITOR_DESCRIPTOR_ASCII)
271 printf("Monitor ID: %s\n",
272 snip(monitor->data.string));
273 else if (monitor->type == EDID_MONITOR_DESCRIPTOR_NAME)
274 printf("Monitor name: %s\n",
275 snip(monitor->data.string));
276 else if (monitor->type == EDID_MONITOR_DESCRIPTOR_RANGE)
277 printf("Monitor range limits, horizontal sync: "
278 "%d-%d kHz, vertical refresh: "
279 "%d-%d Hz, max pixel clock: "
281 monitor->data.range_data.horizontal_min,
282 monitor->data.range_data.horizontal_max,
283 monitor->data.range_data.vertical_min,
284 monitor->data.range_data.vertical_max,
285 monitor->data.range_data.pixel_clock_max * 10);
287 uint32_t pixclock, h_active, h_blanking, v_active, v_blanking;
288 uint32_t h_total, v_total, vfreq;
290 pixclock = EDID_DETAILED_TIMING_PIXEL_CLOCK(*timing);
291 h_active = EDID_DETAILED_TIMING_HORIZONTAL_ACTIVE(*timing);
292 h_blanking = EDID_DETAILED_TIMING_HORIZONTAL_BLANKING(*timing);
293 v_active = EDID_DETAILED_TIMING_VERTICAL_ACTIVE(*timing);
294 v_blanking = EDID_DETAILED_TIMING_VERTICAL_BLANKING(*timing);
296 h_total = h_active + h_blanking;
297 v_total = v_active + v_blanking;
298 if (v_total > 0 && h_total > 0)
299 vfreq = pixclock / (v_total * h_total);
301 vfreq = 1; /* Error case */
302 printf("\t%dx%d\%c\t%d Hz (detailed)\n", h_active,
303 v_active, h_active > 1000 ? ' ' : '\t', vfreq);
309 * Get the manufacturer name from an EDID info.
311 * @param edid_info The EDID info to be printed
312 * @param name Returns the string of the manufacturer name
314 static void edid_get_manufacturer_name(struct edid1_info *edid, char *name)
316 name[0] = EDID1_INFO_MANUFACTURER_NAME_CHAR1(*edid) + 'A' - 1;
317 name[1] = EDID1_INFO_MANUFACTURER_NAME_CHAR2(*edid) + 'A' - 1;
318 name[2] = EDID1_INFO_MANUFACTURER_NAME_CHAR3(*edid) + 'A' - 1;
322 void edid_print_info(struct edid1_info *edid_info)
325 char manufacturer[4];
326 unsigned int have_timing = 0;
327 uint32_t serial_number;
329 if (edid_check_info(edid_info)) {
330 printf("Not a valid EDID\n");
334 printf("EDID version: %d.%d\n",
335 edid_info->version, edid_info->revision);
337 printf("Product ID code: %04x\n", EDID1_INFO_PRODUCT_CODE(*edid_info));
339 edid_get_manufacturer_name(edid_info, manufacturer);
340 printf("Manufacturer: %s\n", manufacturer);
342 serial_number = EDID1_INFO_SERIAL_NUMBER(*edid_info);
343 if (serial_number != 0xffffffff) {
344 if (strcmp(manufacturer, "MAG") == 0)
345 serial_number -= 0x7000000;
346 if (strcmp(manufacturer, "OQI") == 0)
347 serial_number -= 456150000;
348 if (strcmp(manufacturer, "VSC") == 0)
349 serial_number -= 640000000;
351 printf("Serial number: %08x\n", serial_number);
352 printf("Manufactured in week: %d year: %d\n",
353 edid_info->week, edid_info->year + 1990);
355 printf("Video input definition: %svoltage level %d%s%s%s%s%s\n",
356 EDID1_INFO_VIDEO_INPUT_DIGITAL(*edid_info) ?
357 "digital signal, " : "analog signal, ",
358 EDID1_INFO_VIDEO_INPUT_VOLTAGE_LEVEL(*edid_info),
359 EDID1_INFO_VIDEO_INPUT_BLANK_TO_BLACK(*edid_info) ?
360 ", blank to black" : "",
361 EDID1_INFO_VIDEO_INPUT_SEPARATE_SYNC(*edid_info) ?
362 ", separate sync" : "",
363 EDID1_INFO_VIDEO_INPUT_COMPOSITE_SYNC(*edid_info) ?
364 ", composite sync" : "",
365 EDID1_INFO_VIDEO_INPUT_SYNC_ON_GREEN(*edid_info) ?
366 ", sync on green" : "",
367 EDID1_INFO_VIDEO_INPUT_SERRATION_V(*edid_info) ?
368 ", serration v" : "");
370 printf("Monitor is %s\n",
371 EDID1_INFO_FEATURE_RGB(*edid_info) ? "RGB" : "non-RGB");
373 printf("Maximum visible display size: %d cm x %d cm\n",
374 edid_info->max_size_horizontal,
375 edid_info->max_size_vertical);
377 printf("Power management features: %s%s, %s%s, %s%s\n",
378 EDID1_INFO_FEATURE_ACTIVE_OFF(*edid_info) ?
379 "" : "no ", "active off",
380 EDID1_INFO_FEATURE_SUSPEND(*edid_info) ? "" : "no ", "suspend",
381 EDID1_INFO_FEATURE_STANDBY(*edid_info) ? "" : "no ", "standby");
383 printf("Estabilished timings:\n");
384 if (EDID1_INFO_ESTABLISHED_TIMING_720X400_70(*edid_info))
385 printf("\t720x400\t\t70 Hz (VGA 640x400, IBM)\n");
386 if (EDID1_INFO_ESTABLISHED_TIMING_720X400_88(*edid_info))
387 printf("\t720x400\t\t88 Hz (XGA2)\n");
388 if (EDID1_INFO_ESTABLISHED_TIMING_640X480_60(*edid_info))
389 printf("\t640x480\t\t60 Hz (VGA)\n");
390 if (EDID1_INFO_ESTABLISHED_TIMING_640X480_67(*edid_info))
391 printf("\t640x480\t\t67 Hz (Mac II, Apple)\n");
392 if (EDID1_INFO_ESTABLISHED_TIMING_640X480_72(*edid_info))
393 printf("\t640x480\t\t72 Hz (VESA)\n");
394 if (EDID1_INFO_ESTABLISHED_TIMING_640X480_75(*edid_info))
395 printf("\t640x480\t\t75 Hz (VESA)\n");
396 if (EDID1_INFO_ESTABLISHED_TIMING_800X600_56(*edid_info))
397 printf("\t800x600\t\t56 Hz (VESA)\n");
398 if (EDID1_INFO_ESTABLISHED_TIMING_800X600_60(*edid_info))
399 printf("\t800x600\t\t60 Hz (VESA)\n");
400 if (EDID1_INFO_ESTABLISHED_TIMING_800X600_72(*edid_info))
401 printf("\t800x600\t\t72 Hz (VESA)\n");
402 if (EDID1_INFO_ESTABLISHED_TIMING_800X600_75(*edid_info))
403 printf("\t800x600\t\t75 Hz (VESA)\n");
404 if (EDID1_INFO_ESTABLISHED_TIMING_832X624_75(*edid_info))
405 printf("\t832x624\t\t75 Hz (Mac II)\n");
406 if (EDID1_INFO_ESTABLISHED_TIMING_1024X768_87I(*edid_info))
407 printf("\t1024x768\t87 Hz Interlaced (8514A)\n");
408 if (EDID1_INFO_ESTABLISHED_TIMING_1024X768_60(*edid_info))
409 printf("\t1024x768\t60 Hz (VESA)\n");
410 if (EDID1_INFO_ESTABLISHED_TIMING_1024X768_70(*edid_info))
411 printf("\t1024x768\t70 Hz (VESA)\n");
412 if (EDID1_INFO_ESTABLISHED_TIMING_1024X768_75(*edid_info))
413 printf("\t1024x768\t75 Hz (VESA)\n");
414 if (EDID1_INFO_ESTABLISHED_TIMING_1280X1024_75(*edid_info))
415 printf("\t1280x1024\t75 (VESA)\n");
416 if (EDID1_INFO_ESTABLISHED_TIMING_1152X870_75(*edid_info))
417 printf("\t1152x870\t75 (Mac II)\n");
419 /* Standard timings. */
420 printf("Standard timings:\n");
421 for (i = 0; i < ARRAY_SIZE(edid_info->standard_timings); i++) {
422 unsigned int aspect = 10000;
424 unsigned char xres, vfreq;
426 xres = EDID1_INFO_STANDARD_TIMING_XRESOLUTION(*edid_info, i);
427 vfreq = EDID1_INFO_STANDARD_TIMING_VFREQ(*edid_info, i);
428 if ((xres != vfreq) ||
429 ((xres != 0) && (xres != 1)) ||
430 ((vfreq != 0) && (vfreq != 1))) {
431 switch (EDID1_INFO_STANDARD_TIMING_ASPECT(*edid_info,
447 y = x * aspect / 10000;
448 printf("\t%dx%d%c\t%d Hz\n", x, y,
449 x > 1000 ? ' ' : '\t', (vfreq & 0x3f) + 60);
454 /* Detailed timing information. */
455 for (i = 0; i < ARRAY_SIZE(edid_info->monitor_details.descriptor);
457 edid_print_dtd(&edid_info->monitor_details.descriptor[i],