common: edid: Search for valid timing in extension block

One of my monitors have only 4k@60 timing in base EDID block which is out of range for devices with HDMI 1.4. It turns out that it has additional detailed timings in CTA-861 Extension Block and two of them are appropriate for HDMI 1.4. Add additional search for valid detailed timing in extension block. Signed-off-by: Jernej Skrabec <[email protected]> Acked-by: Andre Przywara <[email protected]> Signed-off-by: Andre Przywara <[email protected]>
hramrach · Apr 24, 2021 · a327fee · a327fee
1 parent 3daea86
commit a327fee
Showing 1 changed file with 18 additions and 0 deletions.
diff --git a/common/edid.c b/common/edid.c
@@ -220,6 +220,24 @@ int edid_get_timing_validate(u8 *buf, int buf_size,
 	/* Look for detailed timing in base EDID */
 	found = edid_find_valid_timing(edid->monitor_details.descriptor, 4,
 				       timing, mode_valid, mode_valid_priv);
+
+	/* Look for detailed timing in CTA-861 Extension Block */
+	if (!found && edid->extension_flag && buf_size >= EDID_EXT_SIZE) {
+		struct edid_cea861_info *info =
+			(struct edid_cea861_info *)(buf + sizeof(*edid));
+
+		if (info->extension_tag == EDID_CEA861_EXTENSION_TAG) {
+			int count = EDID_CEA861_DTD_COUNT(*info);
+			int offset = info->dtd_offset;
+			int size = count * sizeof(struct edid_detailed_timing);
+
+			if (offset >= 4 && offset + size < EDID_SIZE)
+				found = edid_find_valid_timing(
+					(u8 *)info + offset, count, timing,
+					mode_valid, mode_valid_priv);
+		}
+	}
+
 	if (!found)
 		return -EINVAL;