diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 2b8e22c..35d46f5 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -3216,6 +3216,7 @@ static u8 *drm_find_displayid_extension(const struct edid *edid,
 					int *length, int *idx)
 {
 	u8 *displayid = drm_find_edid_extension(edid, DISPLAYID_EXT);
+	struct displayid_hdr *base;
 	int ret;
 
 	if (!displayid)
@@ -3228,6 +3229,9 @@ static u8 *drm_find_displayid_extension(const struct edid *edid,
 	if (ret)
 		return NULL;
 
+	base = (struct displayid_hdr *)&displayid[*idx];
+	*length = *idx + sizeof(*base) + base->bytes;
+
 	return displayid;
 }