diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 57daed0b0b36..9e65b4a1c71d 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -852,7 +852,8 @@ static u8 get_pipes_downstream_of_mst_port(struct intel_atomic_state *state,
 		if (&connector->mst.dp->mst.mgr != mst_mgr)
 			continue;
 
-		if (connector->mst.port != parent_port &&
+		if (parent_port &&
+		    connector->mst.port != parent_port &&
 		    !drm_dp_mst_port_downstream_of_parent(mst_mgr,
 							  connector->mst.port,
 							  parent_port))