diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index cac4229..d3a8ef4 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1325,6 +1325,8 @@ again:
 	}
 
 create_mode:
+	printk("RADEK drm_pick_cmdline_mode");
+	WARN_ON(list_empty(&fb_helper_conn->connector->modes));
 	mode = drm_mode_create_from_cmdline_mode(fb_helper_conn->connector->dev,
 						 cmdline_mode);
 	list_add(&mode->head, &fb_helper_conn->connector->modes);
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 6350387..c91acf1 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -89,6 +89,8 @@ static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
 	if (mode == NULL)
 		return 0;
 
+	printk("RADEK drm_helper_probe_add_cmdline_mode");
+	WARN_ON(list_empty(&connector->modes));
 	drm_mode_probed_add(connector, mode);
 	return 1;
 }