diff options
| -rw-r--r-- | drivers/gpu/drm/drm_edid.c | 81 | ||||
| -rw-r--r-- | include/drm/drm_displayid.h | 10 |
2 files changed, 80 insertions, 11 deletions
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 9d8f2b952004..df635afe41b7 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -1342,6 +1342,7 @@ MODULE_PARM_DESC(edid_fixup, static void drm_get_displayid(struct drm_connector *connector, struct edid *edid); +static int validate_displayid(u8 *displayid, int length, int idx); static int drm_edid_block_checksum(const u8 *raw_edid) { @@ -2926,16 +2927,46 @@ static u8 *drm_find_edid_extension(const struct edid *edid, int ext_id) return edid_ext; } -static u8 *drm_find_cea_extension(const struct edid *edid) -{ - return drm_find_edid_extension(edid, CEA_EXT); -} static u8 *drm_find_displayid_extension(const struct edid *edid) { return drm_find_edid_extension(edid, DISPLAYID_EXT); } +static u8 *drm_find_cea_extension(const struct edid *edid) +{ + int ret; + int idx = 1; + int length = EDID_LENGTH; + struct displayid_block *block; + u8 *cea; + u8 *displayid; + + /* Look for a top level CEA extension block */ + cea = drm_find_edid_extension(edid, CEA_EXT); + if (cea) + return cea; + + /* CEA blocks can also be found embedded in a DisplayID block */ + displayid = drm_find_displayid_extension(edid); + if (!displayid) + return NULL; + + ret = validate_displayid(displayid, length, idx); + if (ret) + return NULL; + + idx += sizeof(struct displayid_hdr); + for_each_displayid_db(displayid, block, idx, length) { + if (block->tag == DATA_BLOCK_CTA) { + cea = (u8 *)block; + break; + } + } + + return cea; +} + /* * Calculate the alternate clock for the CEA mode * (60Hz vs. 59.94Hz etc.) @@ -3659,13 +3690,38 @@ cea_revision(const u8 *cea) static int cea_db_offsets(const u8 *cea, int *start, int *end) { - /* Data block offset in CEA extension block */ - *start = 4; - *end = cea[2]; - if (*end == 0) - *end = 127; - if (*end < 4 || *end > 127) - return -ERANGE; + /* DisplayID CTA extension blocks and top-level CEA EDID + * block header definitions differ in the following bytes: + * 1) Byte 2 of the header specifies length differently, + * 2) Byte 3 is only present in the CEA top level block. + * + * The different definitions for byte 2 follow. + * + * DisplayID CTA extension block defines byte 2 as: + * Number of payload bytes + * + * CEA EDID block defines byte 2 as: + * Byte number (decimal) within this block where the 18-byte + * DTDs begin. If no non-DTD data is present in this extension + * block, the value should be set to 04h (the byte after next). + * If set to 00h, there are no DTDs present in this block and + * no non-DTD data. + */ + if (cea[0] == DATA_BLOCK_CTA) { + *start = 3; + *end = *start + cea[2]; + } else if (cea[0] == CEA_EXT) { + /* Data block offset in CEA extension block */ + *start = 4; + *end = cea[2]; + if (*end == 0) + *end = 127; + if (*end < 4 || *end > 127) + return -ERANGE; + } else { + return -ENOTSUPP; + } + return 0; } @@ -5406,6 +5462,9 @@ static int drm_parse_display_id(struct drm_connector *connector, case DATA_BLOCK_TYPE_1_DETAILED_TIMING: /* handled in mode gathering code. */ break; + case DATA_BLOCK_CTA: + /* handled in the cea parser code. */ + break; default: DRM_DEBUG_KMS("found DisplayID tag 0x%x, unhandled\n", block->tag); break; diff --git a/include/drm/drm_displayid.h b/include/drm/drm_displayid.h index c0d4df6a606f..9d3b745c3107 100644 --- a/include/drm/drm_displayid.h +++ b/include/drm/drm_displayid.h @@ -40,6 +40,7 @@ #define DATA_BLOCK_DISPLAY_INTERFACE 0x0f #define DATA_BLOCK_STEREO_DISPLAY_INTERFACE 0x10 #define DATA_BLOCK_TILED_DISPLAY 0x12 +#define DATA_BLOCK_CTA 0x81 #define DATA_BLOCK_VENDOR_SPECIFIC 0x7f @@ -90,4 +91,13 @@ struct displayid_detailed_timing_block { struct displayid_block base; struct displayid_detailed_timings_1 timings[0]; }; + +#define for_each_displayid_db(displayid, block, idx, length) \ + for ((block) = (struct displayid_block *)&(displayid)[idx]; \ + (idx) + sizeof(struct displayid_block) <= (length) && \ + (idx) + sizeof(struct displayid_block) + (block)->num_bytes <= (length) && \ + (block)->num_bytes > 0; \ + (idx) += (block)->num_bytes + sizeof(struct displayid_block), \ + (block) = (struct displayid_block *)&(displayid)[idx]) + #endif |