drm/edid: parse CEA blocks embedded in DisplayID (e28ad544) · Commits · 戴 / test

drivers/gpu/drm/drm_edid.c

+70 −11

Original line number	Diff line number	Diff line
		@@ -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.)
		@@ -3659,6 +3690,27 @@ cea_revision(const u8 *cea)
		static int
		cea_db_offsets(const u8 cea, int start, int *end)
		{
		/* 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];
		@@ -3666,6 +3718,10 @@ cea_db_offsets(const u8 cea, int start, int *end)
		*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;

include/drm/drm_displayid.h

+10 −0

Original line number	Diff line number	Diff line
		@@ -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

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