diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 7998ee66b317..b98384dbd9a7 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -115,6 +115,7 @@ void drm_vblank_cleanup(struct drm_device *dev)
 
 	dev->num_crtcs = 0;
 }
+EXPORT_SYMBOL(drm_vblank_cleanup);
 
 int drm_vblank_init(struct drm_device *dev, int num_crtcs)
 {
@@ -163,7 +164,6 @@ int drm_vblank_init(struct drm_device *dev, int num_crtcs)
 	}
 
 	dev->vblank_disable_allowed = 0;
-
 	return 0;
 
 err:
@@ -493,6 +493,9 @@ EXPORT_SYMBOL(drm_vblank_off);
  */
 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
 {
+	/* vblank is not initialized (IRQ not installed ?) */
+	if (!dev->num_crtcs)
+		return;
 	/*
 	 * To avoid all the problems that might happen if interrupts
 	 * were enabled/disabled around or between these calls, we just