1 // SPDX-License-Identifier: GPL-2.0+
3 * Copyright (c) 2012 The Chromium OS Authors.
6 * Petr Stetiar <ynezz@true.cz>
8 * Contains stolen code from ddcprobe project which is:
9 * Copyright (C) Nalin Dahyabhai <bigfun@pobox.com>
16 #include <linux/ctype.h>
17 #include <linux/string.h>
19 int edid_check_info(struct edid1_info
*edid_info
)
21 if ((edid_info
== NULL
) || (edid_info
->version
== 0))
24 if (memcmp(edid_info
->header
, "\x0\xff\xff\xff\xff\xff\xff\x0", 8))
27 if (edid_info
->version
== 0xff && edid_info
->revision
== 0xff)
33 int edid_check_checksum(u8
*edid_block
)
38 for (i
= 0; i
< 128; i
++)
39 checksum
+= edid_block
[i
];
41 return (checksum
== 0) ? 0 : -EINVAL
;
44 int edid_get_ranges(struct edid1_info
*edid
, unsigned int *hmin
,
45 unsigned int *hmax
, unsigned int *vmin
,
49 struct edid_monitor_descriptor
*monitor
;
51 *hmin
= *hmax
= *vmin
= *vmax
= 0;
52 if (edid_check_info(edid
))
55 for (i
= 0; i
< ARRAY_SIZE(edid
->monitor_details
.descriptor
); i
++) {
56 monitor
= &edid
->monitor_details
.descriptor
[i
];
57 if (monitor
->type
== EDID_MONITOR_DESCRIPTOR_RANGE
) {
58 *hmin
= monitor
->data
.range_data
.horizontal_min
;
59 *hmax
= monitor
->data
.range_data
.horizontal_max
;
60 *vmin
= monitor
->data
.range_data
.vertical_min
;
61 *vmax
= monitor
->data
.range_data
.vertical_max
;
68 /* Set all parts of a timing entry to the same value */
69 static void set_entry(struct timing_entry
*entry
, u32 value
)
77 * decode_timing() - Decoding an 18-byte detailed timing record
79 * @buf: Pointer to EDID detailed timing record
80 * @timing: Place to put timing
82 static void decode_timing(u8
*buf
, struct display_timing
*timing
)
85 unsigned int ha
, hbl
, hso
, hspw
, hborder
;
86 unsigned int va
, vbl
, vso
, vspw
, vborder
;
87 struct edid_detailed_timing
*t
= (struct edid_detailed_timing
*)buf
;
89 /* Edid contains pixel clock in terms of 10KHz */
90 set_entry(&timing
->pixelclock
, (buf
[0] + (buf
[1] << 8)) * 10000);
91 x_mm
= (buf
[12] + ((buf
[14] & 0xf0) << 4));
92 y_mm
= (buf
[13] + ((buf
[14] & 0x0f) << 8));
93 ha
= (buf
[2] + ((buf
[4] & 0xf0) << 4));
94 hbl
= (buf
[3] + ((buf
[4] & 0x0f) << 8));
95 hso
= (buf
[8] + ((buf
[11] & 0xc0) << 2));
96 hspw
= (buf
[9] + ((buf
[11] & 0x30) << 4));
98 va
= (buf
[5] + ((buf
[7] & 0xf0) << 4));
99 vbl
= (buf
[6] + ((buf
[7] & 0x0f) << 8));
100 vso
= ((buf
[10] >> 4) + ((buf
[11] & 0x0c) << 2));
101 vspw
= ((buf
[10] & 0x0f) + ((buf
[11] & 0x03) << 4));
104 set_entry(&timing
->hactive
, ha
);
105 set_entry(&timing
->hfront_porch
, hso
);
106 set_entry(&timing
->hback_porch
, hbl
- hso
- hspw
);
107 set_entry(&timing
->hsync_len
, hspw
);
109 set_entry(&timing
->vactive
, va
);
110 set_entry(&timing
->vfront_porch
, vso
);
111 set_entry(&timing
->vback_porch
, vbl
- vso
- vspw
);
112 set_entry(&timing
->vsync_len
, vspw
);
115 if (EDID_DETAILED_TIMING_FLAG_HSYNC_POLARITY(*t
))
116 timing
->flags
|= DISPLAY_FLAGS_HSYNC_HIGH
;
118 timing
->flags
|= DISPLAY_FLAGS_HSYNC_LOW
;
119 if (EDID_DETAILED_TIMING_FLAG_VSYNC_POLARITY(*t
))
120 timing
->flags
|= DISPLAY_FLAGS_VSYNC_HIGH
;
122 timing
->flags
|= DISPLAY_FLAGS_VSYNC_LOW
;
124 if (EDID_DETAILED_TIMING_FLAG_INTERLACED(*t
))
125 timing
->flags
= DISPLAY_FLAGS_INTERLACED
;
127 debug("Detailed mode clock %u Hz, %d mm x %d mm\n"
128 " %04x %04x %04x %04x hborder %x\n"
129 " %04x %04x %04x %04x vborder %x\n",
130 timing
->pixelclock
.typ
,
132 ha
, ha
+ hso
, ha
+ hso
+ hspw
,
134 va
, va
+ vso
, va
+ vso
+ vspw
,
139 * Check if HDMI vendor specific data block is present in CEA block
140 * @param info CEA extension block
141 * @return true if block is found
143 static bool cea_is_hdmi_vsdb_present(struct edid_cea861_info
*info
)
147 /* check for end of data block */
148 end
= info
->dtd_offset
;
150 end
= sizeof(info
->data
);
151 if (end
< 4 || end
> sizeof(info
->data
))
156 /* Look for vendor specific data block of appropriate size */
157 if ((EDID_CEA861_DB_TYPE(*info
, i
) == EDID_CEA861_DB_VENDOR
) &&
158 (EDID_CEA861_DB_LEN(*info
, i
) >= 5)) {
159 u8
*db
= &info
->data
[i
+ 1];
160 u32 oui
= db
[0] | (db
[1] << 8) | (db
[2] << 16);
162 if (oui
== HDMI_IEEE_OUI
)
165 i
+= EDID_CEA861_DB_LEN(*info
, i
) + 1;
171 int edid_get_timing_validate(u8
*buf
, int buf_size
,
172 struct display_timing
*timing
,
173 int *panel_bits_per_colourp
,
174 bool (*mode_valid
)(void *priv
,
175 const struct display_timing
*timing
),
176 void *mode_valid_priv
)
178 struct edid1_info
*edid
= (struct edid1_info
*)buf
;
182 if (buf_size
< sizeof(*edid
) || edid_check_info(edid
)) {
183 debug("%s: Invalid buffer\n", __func__
);
187 if (!EDID1_INFO_FEATURE_PREFERRED_TIMING_MODE(*edid
)) {
188 debug("%s: No preferred timing\n", __func__
);
192 /* Look for detailed timing */
194 for (i
= 0; i
< 4; i
++) {
195 struct edid_monitor_descriptor
*desc
;
197 desc
= &edid
->monitor_details
.descriptor
[i
];
198 if (desc
->zero_flag_1
!= 0) {
199 decode_timing((u8
*)desc
, timing
);
201 timing_done
= mode_valid(mode_valid_priv
,
213 if (!EDID1_INFO_VIDEO_INPUT_DIGITAL(*edid
)) {
214 debug("%s: Not a digital display\n", __func__
);
217 if (edid
->version
!= 1 || edid
->revision
< 4) {
218 debug("%s: EDID version %d.%d does not have required info\n",
219 __func__
, edid
->version
, edid
->revision
);
220 *panel_bits_per_colourp
= -1;
222 *panel_bits_per_colourp
=
223 ((edid
->video_input_definition
& 0x70) >> 3) + 4;
226 timing
->hdmi_monitor
= false;
227 if (edid
->extension_flag
&& (buf_size
>= EDID_EXT_SIZE
)) {
228 struct edid_cea861_info
*info
=
229 (struct edid_cea861_info
*)(buf
+ sizeof(*edid
));
231 if (info
->extension_tag
== EDID_CEA861_EXTENSION_TAG
)
232 timing
->hdmi_monitor
= cea_is_hdmi_vsdb_present(info
);
238 int edid_get_timing(u8
*buf
, int buf_size
, struct display_timing
*timing
,
239 int *panel_bits_per_colourp
)
241 return edid_get_timing_validate(buf
, buf_size
, timing
,
242 panel_bits_per_colourp
, NULL
, NULL
);
247 * Snip the tailing whitespace/return of a string.
249 * @param string The string to be snipped
250 * @return the snipped string
252 static char *snip(char *string
)
257 * This is always a 13 character buffer
258 * and it's not always terminated.
261 s
= &string
[strlen(string
) - 1];
263 while (s
>= string
&& (isspace(*s
) || *s
== '\n' || *s
== '\r' ||
271 * Print an EDID monitor descriptor block
273 * @param monitor The EDID monitor descriptor block
274 * @have_timing Modifies to 1 if the desciptor contains timing info
276 static void edid_print_dtd(struct edid_monitor_descriptor
*monitor
,
277 unsigned int *have_timing
)
279 unsigned char *bytes
= (unsigned char *)monitor
;
280 struct edid_detailed_timing
*timing
=
281 (struct edid_detailed_timing
*)monitor
;
283 if (bytes
[0] == 0 && bytes
[1] == 0) {
284 if (monitor
->type
== EDID_MONITOR_DESCRIPTOR_SERIAL
)
285 printf("Monitor serial number: %s\n",
286 snip(monitor
->data
.string
));
287 else if (monitor
->type
== EDID_MONITOR_DESCRIPTOR_ASCII
)
288 printf("Monitor ID: %s\n",
289 snip(monitor
->data
.string
));
290 else if (monitor
->type
== EDID_MONITOR_DESCRIPTOR_NAME
)
291 printf("Monitor name: %s\n",
292 snip(monitor
->data
.string
));
293 else if (monitor
->type
== EDID_MONITOR_DESCRIPTOR_RANGE
)
294 printf("Monitor range limits, horizontal sync: "
295 "%d-%d kHz, vertical refresh: "
296 "%d-%d Hz, max pixel clock: "
298 monitor
->data
.range_data
.horizontal_min
,
299 monitor
->data
.range_data
.horizontal_max
,
300 monitor
->data
.range_data
.vertical_min
,
301 monitor
->data
.range_data
.vertical_max
,
302 monitor
->data
.range_data
.pixel_clock_max
* 10);
304 uint32_t pixclock
, h_active
, h_blanking
, v_active
, v_blanking
;
305 uint32_t h_total
, v_total
, vfreq
;
307 pixclock
= EDID_DETAILED_TIMING_PIXEL_CLOCK(*timing
);
308 h_active
= EDID_DETAILED_TIMING_HORIZONTAL_ACTIVE(*timing
);
309 h_blanking
= EDID_DETAILED_TIMING_HORIZONTAL_BLANKING(*timing
);
310 v_active
= EDID_DETAILED_TIMING_VERTICAL_ACTIVE(*timing
);
311 v_blanking
= EDID_DETAILED_TIMING_VERTICAL_BLANKING(*timing
);
313 h_total
= h_active
+ h_blanking
;
314 v_total
= v_active
+ v_blanking
;
315 if (v_total
> 0 && h_total
> 0)
316 vfreq
= pixclock
/ (v_total
* h_total
);
318 vfreq
= 1; /* Error case */
319 printf("\t%dx%d\%c\t%d Hz (detailed)\n", h_active
,
320 v_active
, h_active
> 1000 ? ' ' : '\t', vfreq
);
326 * Get the manufacturer name from an EDID info.
328 * @param edid_info The EDID info to be printed
329 * @param name Returns the string of the manufacturer name
331 static void edid_get_manufacturer_name(struct edid1_info
*edid
, char *name
)
333 name
[0] = EDID1_INFO_MANUFACTURER_NAME_CHAR1(*edid
) + 'A' - 1;
334 name
[1] = EDID1_INFO_MANUFACTURER_NAME_CHAR2(*edid
) + 'A' - 1;
335 name
[2] = EDID1_INFO_MANUFACTURER_NAME_CHAR3(*edid
) + 'A' - 1;
339 void edid_print_info(struct edid1_info
*edid_info
)
342 char manufacturer
[4];
343 unsigned int have_timing
= 0;
344 uint32_t serial_number
;
346 if (edid_check_info(edid_info
)) {
347 printf("Not a valid EDID\n");
351 printf("EDID version: %d.%d\n",
352 edid_info
->version
, edid_info
->revision
);
354 printf("Product ID code: %04x\n", EDID1_INFO_PRODUCT_CODE(*edid_info
));
356 edid_get_manufacturer_name(edid_info
, manufacturer
);
357 printf("Manufacturer: %s\n", manufacturer
);
359 serial_number
= EDID1_INFO_SERIAL_NUMBER(*edid_info
);
360 if (serial_number
!= 0xffffffff) {
361 if (strcmp(manufacturer
, "MAG") == 0)
362 serial_number
-= 0x7000000;
363 if (strcmp(manufacturer
, "OQI") == 0)
364 serial_number
-= 456150000;
365 if (strcmp(manufacturer
, "VSC") == 0)
366 serial_number
-= 640000000;
368 printf("Serial number: %08x\n", serial_number
);
369 printf("Manufactured in week: %d year: %d\n",
370 edid_info
->week
, edid_info
->year
+ 1990);
372 printf("Video input definition: %svoltage level %d%s%s%s%s%s\n",
373 EDID1_INFO_VIDEO_INPUT_DIGITAL(*edid_info
) ?
374 "digital signal, " : "analog signal, ",
375 EDID1_INFO_VIDEO_INPUT_VOLTAGE_LEVEL(*edid_info
),
376 EDID1_INFO_VIDEO_INPUT_BLANK_TO_BLACK(*edid_info
) ?
377 ", blank to black" : "",
378 EDID1_INFO_VIDEO_INPUT_SEPARATE_SYNC(*edid_info
) ?
379 ", separate sync" : "",
380 EDID1_INFO_VIDEO_INPUT_COMPOSITE_SYNC(*edid_info
) ?
381 ", composite sync" : "",
382 EDID1_INFO_VIDEO_INPUT_SYNC_ON_GREEN(*edid_info
) ?
383 ", sync on green" : "",
384 EDID1_INFO_VIDEO_INPUT_SERRATION_V(*edid_info
) ?
385 ", serration v" : "");
387 printf("Monitor is %s\n",
388 EDID1_INFO_FEATURE_RGB(*edid_info
) ? "RGB" : "non-RGB");
390 printf("Maximum visible display size: %d cm x %d cm\n",
391 edid_info
->max_size_horizontal
,
392 edid_info
->max_size_vertical
);
394 printf("Power management features: %s%s, %s%s, %s%s\n",
395 EDID1_INFO_FEATURE_ACTIVE_OFF(*edid_info
) ?
396 "" : "no ", "active off",
397 EDID1_INFO_FEATURE_SUSPEND(*edid_info
) ? "" : "no ", "suspend",
398 EDID1_INFO_FEATURE_STANDBY(*edid_info
) ? "" : "no ", "standby");
400 printf("Estabilished timings:\n");
401 if (EDID1_INFO_ESTABLISHED_TIMING_720X400_70(*edid_info
))
402 printf("\t720x400\t\t70 Hz (VGA 640x400, IBM)\n");
403 if (EDID1_INFO_ESTABLISHED_TIMING_720X400_88(*edid_info
))
404 printf("\t720x400\t\t88 Hz (XGA2)\n");
405 if (EDID1_INFO_ESTABLISHED_TIMING_640X480_60(*edid_info
))
406 printf("\t640x480\t\t60 Hz (VGA)\n");
407 if (EDID1_INFO_ESTABLISHED_TIMING_640X480_67(*edid_info
))
408 printf("\t640x480\t\t67 Hz (Mac II, Apple)\n");
409 if (EDID1_INFO_ESTABLISHED_TIMING_640X480_72(*edid_info
))
410 printf("\t640x480\t\t72 Hz (VESA)\n");
411 if (EDID1_INFO_ESTABLISHED_TIMING_640X480_75(*edid_info
))
412 printf("\t640x480\t\t75 Hz (VESA)\n");
413 if (EDID1_INFO_ESTABLISHED_TIMING_800X600_56(*edid_info
))
414 printf("\t800x600\t\t56 Hz (VESA)\n");
415 if (EDID1_INFO_ESTABLISHED_TIMING_800X600_60(*edid_info
))
416 printf("\t800x600\t\t60 Hz (VESA)\n");
417 if (EDID1_INFO_ESTABLISHED_TIMING_800X600_72(*edid_info
))
418 printf("\t800x600\t\t72 Hz (VESA)\n");
419 if (EDID1_INFO_ESTABLISHED_TIMING_800X600_75(*edid_info
))
420 printf("\t800x600\t\t75 Hz (VESA)\n");
421 if (EDID1_INFO_ESTABLISHED_TIMING_832X624_75(*edid_info
))
422 printf("\t832x624\t\t75 Hz (Mac II)\n");
423 if (EDID1_INFO_ESTABLISHED_TIMING_1024X768_87I(*edid_info
))
424 printf("\t1024x768\t87 Hz Interlaced (8514A)\n");
425 if (EDID1_INFO_ESTABLISHED_TIMING_1024X768_60(*edid_info
))
426 printf("\t1024x768\t60 Hz (VESA)\n");
427 if (EDID1_INFO_ESTABLISHED_TIMING_1024X768_70(*edid_info
))
428 printf("\t1024x768\t70 Hz (VESA)\n");
429 if (EDID1_INFO_ESTABLISHED_TIMING_1024X768_75(*edid_info
))
430 printf("\t1024x768\t75 Hz (VESA)\n");
431 if (EDID1_INFO_ESTABLISHED_TIMING_1280X1024_75(*edid_info
))
432 printf("\t1280x1024\t75 (VESA)\n");
433 if (EDID1_INFO_ESTABLISHED_TIMING_1152X870_75(*edid_info
))
434 printf("\t1152x870\t75 (Mac II)\n");
436 /* Standard timings. */
437 printf("Standard timings:\n");
438 for (i
= 0; i
< ARRAY_SIZE(edid_info
->standard_timings
); i
++) {
439 unsigned int aspect
= 10000;
441 unsigned char xres
, vfreq
;
443 xres
= EDID1_INFO_STANDARD_TIMING_XRESOLUTION(*edid_info
, i
);
444 vfreq
= EDID1_INFO_STANDARD_TIMING_VFREQ(*edid_info
, i
);
445 if ((xres
!= vfreq
) ||
446 ((xres
!= 0) && (xres
!= 1)) ||
447 ((vfreq
!= 0) && (vfreq
!= 1))) {
448 switch (EDID1_INFO_STANDARD_TIMING_ASPECT(*edid_info
,
464 y
= x
* aspect
/ 10000;
465 printf("\t%dx%d%c\t%d Hz\n", x
, y
,
466 x
> 1000 ? ' ' : '\t', (vfreq
& 0x3f) + 60);
471 /* Detailed timing information. */
472 for (i
= 0; i
< ARRAY_SIZE(edid_info
->monitor_details
.descriptor
);
474 edid_print_dtd(&edid_info
->monitor_details
.descriptor
[i
],