Commit 4ba0f53c authored by Jani Nikula's avatar Jani Nikula
Browse files

drm/edid: add edid_block_tag() helper to get the EDID extension tag 



The extension tag at offset 0 is not present in struct edid, add a
helper for it to reduce the need to use u8 *.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/3f27c67db63c186a48e83fdee2d1ac8a17714e78.1648752228.git.jani.nikula@intel.com
parent 70e49ebe

drivers/gpu/drm/drm_edid.c

+10 −3
Original line number Diff line number Diff line
@@ -1618,6 +1618,13 @@ static int edid_block_get_checksum(const void *_block) 
	return block->checksum;

}



static int edid_block_tag(const void *_block)

{

	const u8 *block = _block;



	return block[0];

}



static bool drm_edid_is_zero(const u8 *in_edid, int length)

{

	if (memchr_inv(in_edid, 0, length))
@@ -1710,7 +1717,7 @@ bool drm_edid_block_valid(u8 *raw_edid, int block, bool print_bad_edid, 
			*edid_corrupt = true;



		/* allow CEA to slide through, switches mangle this */

		if (raw_edid[0] == CEA_EXT) {

		if (edid_block_tag(raw_edid) == CEA_EXT) {

			DRM_DEBUG("EDID checksum is invalid, remainder is %d\n", csum);

			DRM_DEBUG("Assuming a KVM switch modified the CEA block but left the original checksum\n");

		} else {
@@ -1722,7 +1729,7 @@ bool drm_edid_block_valid(u8 *raw_edid, int block, bool print_bad_edid, 
	}



	/* per-block-type checks */

	switch (raw_edid[0]) {

	switch (edid_block_tag(raw_edid)) {

	case 0: /* base */

		if (edid->version != 1) {

			DRM_NOTE("EDID has major version %d, instead of 1\n", edid->version);
@@ -3366,7 +3373,7 @@ const u8 *drm_find_edid_extension(const struct edid *edid, 
	/* Find CEA extension */

	for (i = *ext_index; i < edid->extensions; i++) {

		edid_ext = (const u8 *)edid + EDID_LENGTH * (i + 1);

		if (edid_ext[0] == ext_id)

		if (edid_block_tag(edid_ext) == ext_id)

			break;

	}