diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index 09c1c4ff93ca..4c8acba733ec 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -967,11 +967,15 @@ static int drm_vblank_get(struct drm_device *dev, unsigned int pipe)
 	unsigned long irqflags;
 	int ret = 0;
 
-	if (!dev->num_crtcs)
+	if (!dev->num_crtcs) {
+		DRM_WARN_ONCE("dev->num_crtcs == 0\n");
 		return -EINVAL;
+	}
 
-	if (WARN_ON(pipe >= dev->num_crtcs))
+	if (WARN_ON(pipe >= dev->num_crtcs)) {
+		DRM_WARN_ONCE("pipe=%d >= dev->num_crtcs=%d\n", pipe, dev->num_crtcs);
 		return -EINVAL;
+	}
 
 	spin_lock_irqsave(&dev->vbl_lock, irqflags);
 	/* Going from 0->1 means we have to enable interrupts again */
@@ -980,6 +984,8 @@ static int drm_vblank_get(struct drm_device *dev, unsigned int pipe)
 	} else {
 		if (!vblank->enabled) {
 			atomic_dec(&vblank->refcount);
+			DRM_WARN_ONCE("vblank->refcount restored to %d due to !vblank->enabled\n",
+				      atomic_read(&vblank->refcount));
 			ret = -EINVAL;
 		}
 	}