diff --git a/drivers/gpu/drm/drm_displayid.c b/drivers/gpu/drm/drm_displayid.c
index 32da557b960f..dc649a9efaa2 100644
--- a/drivers/gpu/drm/drm_displayid.c
+++ b/drivers/gpu/drm/drm_displayid.c
@@ -37,7 +37,10 @@ static const u8 *drm_find_displayid_extension(const struct edid *edid,
 					      int *length, int *idx,
 					      int *ext_index)
 {
-	const u8 *displayid = drm_find_edid_extension(edid, DISPLAYID_EXT, ext_index);
+	const u8 *displayid = drm_find_edid_extension(edid,
+						      DISPLAYID_EXT,
+						      ext_index,
+						      edid->extensions);
 	const struct displayid_header *base;
 	int ret;
 
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 890038758660..40c192587f0a 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -3360,23 +3360,23 @@ add_detailed_modes(struct drm_connector *connector, struct edid *edid,
  * Search EDID for CEA extension block.
  */
 const u8 *drm_find_edid_extension(const struct edid *edid,
-				  int ext_id, int *ext_index)
+				  int ext_id, int *ext_index, int ext_blk_num)
 {
 	const u8 *edid_ext = NULL;
 	int i;
 
 	/* No EDID or EDID extensions */
-	if (edid == NULL || edid->extensions == 0)
+	if (edid == NULL || edid->extensions == 0 || *ext_index >= ext_blk_num)
 		return NULL;
 
 	/* Find CEA extension */
-	for (i = *ext_index; i < edid->extensions; i++) {
+	for (i = *ext_index; i < ext_blk_num; i++) {
 		edid_ext = (const u8 *)edid + EDID_LENGTH * (i + 1);
 		if (edid_ext[0] == ext_id)
 			break;
 	}
 
-	if (i >= edid->extensions)
+	if (i >= ext_blk_num)
 		return NULL;
 
 	*ext_index = i + 1;
@@ -3384,14 +3384,15 @@ const u8 *drm_find_edid_extension(const struct edid *edid,
 	return edid_ext;
 }
 
-static const u8 *drm_find_cea_extension(const struct edid *edid, int *ext_index)
+static const u8 *drm_find_cea_extension(const struct edid *edid,
+					int *ext_index, int ext_blk_num)
 {
 	const struct displayid_block *block;
 	struct displayid_iter iter;
 	const u8 *cea;
 
 	/* Look for a CEA extension block from ext_index */
-	cea = drm_find_edid_extension(edid, CEA_EXT, ext_index);
+	cea = drm_find_edid_extension(edid, CEA_EXT, ext_index, ext_blk_num);
 	if (cea)
 		return cea;
 
@@ -3675,7 +3676,7 @@ add_alternate_cea_modes(struct drm_connector *connector, struct edid *edid)
 	int modes = 0, ext_index = 0;
 
 	/* Don't add CEA modes if the CEA extension block is missing */
-	if (!drm_find_cea_extension(edid, &ext_index))
+	if (!drm_find_cea_extension(edid, &ext_index, edid->extensions))
 		return 0;
 
 	/*
@@ -4327,7 +4328,7 @@ size_t drm_edid_read_hf_eeodb_blk_count(const struct edid *edid)
 	int i, start, end, ext_index = 0;
 
 	if (edid->extensions) {
-		cea = drm_find_cea_extension(edid, &ext_index);
+		cea = drm_find_cea_extension(edid, &ext_index, edid->extensions);
 
 		if (cea && !cea_db_offsets(cea, &start, &end))
 			for_each_cea_db(cea, i, start, end)
@@ -4384,13 +4385,17 @@ add_cea_modes(struct drm_connector *connector, struct edid *edid)
 {
 	int modes = 0, ext_index = 0;
 	const u8 *cur_cea = NULL;
+	int ext_blk_num = drm_edid_read_hf_eeodb_blk_count(edid);
+
+	if (!ext_blk_num)
+		ext_blk_num = edid->extensions;
 
 	for (;;) {
 		const u8 *cea, *db, *hdmi = NULL, *video = NULL;
 		u8 dbl, hdmi_len = 0, video_len = 0;
 		int i, start, end;
 
-		cea = drm_find_cea_extension(edid, &ext_index);
+		cea = drm_find_cea_extension(edid, &ext_index, ext_blk_num);
 		if (!cea || cea == cur_cea)
 			break;
 		cur_cea = cea;
@@ -4640,7 +4645,7 @@ static void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid)
 	if (!edid)
 		return;
 
-	cea = drm_find_cea_extension(edid, &ext_index);
+	cea = drm_find_cea_extension(edid, &ext_index, edid->extensions);
 	if (!cea) {
 		DRM_DEBUG_KMS("ELD: no CEA Extension found\n");
 		return;
@@ -4728,7 +4733,7 @@ int drm_edid_to_sad(struct edid *edid, struct cea_sad **sads)
 	int i, start, end, dbl;
 	const u8 *cea;
 
-	cea = drm_find_cea_extension(edid, &ext_index);
+	cea = drm_find_cea_extension(edid, &ext_index, edid->extensions);
 	if (!cea) {
 		DRM_DEBUG_KMS("SAD: no CEA Extension found\n");
 		return 0;
@@ -4790,7 +4795,7 @@ int drm_edid_to_speaker_allocation(struct edid *edid, u8 **sadb)
 	int i, start, end, dbl;
 	const u8 *cea;
 
-	cea = drm_find_cea_extension(edid, &ext_index);
+	cea = drm_find_cea_extension(edid, &ext_index, edid->extensions);
 	if (!cea) {
 		DRM_DEBUG_KMS("SAD: no CEA Extension found\n");
 		return 0;
@@ -4885,7 +4890,7 @@ bool drm_detect_hdmi_monitor(struct edid *edid)
 	int i;
 	int start_offset, end_offset, ext_index = 0;
 
-	edid_ext = drm_find_cea_extension(edid, &ext_index);
+	edid_ext = drm_find_cea_extension(edid, &ext_index, edid->extensions);
 	if (!edid_ext)
 		return false;
 
@@ -4924,7 +4929,7 @@ bool drm_detect_monitor_audio(struct edid *edid)
 	bool has_audio = false;
 	int start_offset, end_offset, ext_index = 0;
 
-	edid_ext = drm_find_cea_extension(edid, &ext_index);
+	edid_ext = drm_find_cea_extension(edid, &ext_index, edid->extensions);
 	if (!edid_ext)
 		goto end;
 
@@ -5248,7 +5253,7 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
 	const u8 *edid_ext;
 	int i, start, end, ext_index = 0;
 
-	edid_ext = drm_find_cea_extension(edid, &ext_index);
+	edid_ext = drm_find_cea_extension(edid, &ext_index, edid->extensions);
 	if (!edid_ext)
 		return;
 
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index 5549da7bd7be..5555b27e92f9 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -591,7 +591,7 @@ struct drm_display_mode *
 drm_display_mode_from_cea_vic(struct drm_device *dev,
 			      u8 video_code);
 const u8 *drm_find_edid_extension(const struct edid *edid,
-				  int ext_id, int *ext_index);
+				  int ext_id, int *ext_index, int ext_blk_num);
 size_t drm_edid_read_hf_eeodb_blk_count(const struct edid *edid);
 
 #endif /* __DRM_EDID_H__ */
