drm/amd/display: Add debug entry to destroy disconnected edp link

Add a flag to dc_debug_options to determine if a disconnected edp link
should be destroyed.
Signed-off-by: Lewis Huang <Lewis.Huang@amd.com>
Reviewed-by: Yongqiang Sun <yongqiang.sun@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc.c

@@ -180,13 +180,25 @@ static bool create_links(
 		link = link_create(&link_init_params);
 
 		if (link) {
-			if (dc->config.edp_not_connected &&
-					link->connector_signal == SIGNAL_TYPE_EDP) {
-				link_destroy(&link);
-			} else {
+			bool should_destory_link = false;
+
+			if (link->connector_signal == SIGNAL_TYPE_EDP) {
+				if (dc->config.edp_not_connected)
+					should_destory_link = true;
+				else if (dc->debug.remove_disconnect_edp) {
+					enum dc_connection_type type;
+					dc_link_detect_sink(link, &type);
+					if (type == dc_connection_none)
+						should_destory_link = true;
+				}
+			}
+
+			if (!should_destory_link) {
 				dc->links[dc->link_count] = link;
 				link->dc = dc;
 				++dc->link_count;
+			} else {
+				link_destroy(&link);
 			}
 		}
 	}

drivers/gpu/drm/amd/display/dc/dc.h

@@ -378,6 +378,7 @@ struct dc_debug_options {
 	bool scl_reset_length10;
 	bool hdmi20_disable;
 	bool skip_detection_link_training;
+	bool remove_disconnect_edp;
 	unsigned int force_odm_combine; //bit vector based on otg inst
 	unsigned int force_fclk_khz;
 	bool disable_tri_buf;