1 files changed, 47 insertions, 21 deletions

diff --git a/common/edid.c b/common/edid.c
index 553ab8fd01..fa85bcd6a1 100644
--- a/common/edid.c
+++ b/common/edid.c
@@ -169,6 +169,29 @@ static bool cea_is_hdmi_vsdb_present(struct edid_cea861_info *info)
 	return false;
 }
 
+static bool edid_find_valid_timing(void *buf, int count,
+				   struct display_timing *timing,
+				   bool (*mode_valid)(void *priv,
+					const struct display_timing *timing),
+				   void *mode_valid_priv)
+{
+	struct edid_detailed_timing *t = buf;
+	bool found = false;
+	int i;
+
+	for (i = 0; i < count && !found; i++, t++)
+		if (EDID_DETAILED_TIMING_PIXEL_CLOCK(*t) != 0) {
+			decode_timing((u8 *)t, timing);
+			if (mode_valid)
+				found = mode_valid(mode_valid_priv,
+						   timing);
+			else
+				found = true;
+		}
+
+	return found;
+}
+
 int edid_get_timing_validate(u8 *buf, int buf_size,
 			     struct display_timing *timing,
 			     int *panel_bits_per_colourp,
@@ -177,44 +200,47 @@ int edid_get_timing_validate(u8 *buf, int buf_size,
 			     void *mode_valid_priv)
 {
 	struct edid1_info *edid = (struct edid1_info *)buf;
-	bool timing_done;
-	int i;
+	bool found;
 
 	if (buf_size < sizeof(*edid) || edid_check_info(edid)) {
 		debug("%s: Invalid buffer\n", __func__);
 		return -EINVAL;
 	}
 
+	if (!EDID1_INFO_VIDEO_INPUT_DIGITAL(*edid)) {
+		debug("%s: Not a digital display\n", __func__);
+		return -ENOSYS;
+	}
+
 	if (!EDID1_INFO_FEATURE_PREFERRED_TIMING_MODE(*edid)) {
 		debug("%s: No preferred timing\n", __func__);
 		return -ENOENT;
 	}
 
-	/* Look for detailed timing */
-	timing_done = false;
-	for (i = 0; i < 4; i++) {
-		struct edid_monitor_descriptor *desc;
+	/* Look for detailed timing in base EDID */
+	found = edid_find_valid_timing(edid->monitor_details.descriptor, 4,
+				       timing, mode_valid, mode_valid_priv);
 
-		desc = &edid->monitor_details.descriptor[i];
-		if (desc->zero_flag_1 != 0) {
-			decode_timing((u8 *)desc, timing);
-			if (mode_valid)
-				timing_done = mode_valid(mode_valid_priv,
-							 timing);
-			else
-				timing_done = true;
+	/* 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 (timing_done)
-				break;
+		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 (!timing_done)
+
+	if (!found)
 		return -EINVAL;
 
-	if (!EDID1_INFO_VIDEO_INPUT_DIGITAL(*edid)) {
-		debug("%s: Not a digital display\n", __func__);
-		return -ENOSYS;
-	}
 	if (edid->version != 1 || edid->revision < 4) {
 		debug("%s: EDID version %d.%d does not have required info\n",
 		      __func__, edid->version, edid->revision);