--- zzzz-none-000/linux-3.10.107/drivers/gpu/drm/ttm/ttm_lock.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/gpu/drm/ttm/ttm_lock.c	2021-02-04 17:41:59.000000000 +0000
@@ -180,20 +180,12 @@
 			spin_unlock(&lock->lock);
 		}
 	} else
-		wait_event(lock->queue, __ttm_read_lock(lock));
+		wait_event(lock->queue, __ttm_write_lock(lock));
 
 	return ret;
 }
 EXPORT_SYMBOL(ttm_write_lock);
 
-void ttm_write_lock_downgrade(struct ttm_lock *lock)
-{
-	spin_lock(&lock->lock);
-	lock->rw = 1;
-	wake_up_all(&lock->queue);
-	spin_unlock(&lock->lock);
-}
-
 static int __ttm_vt_unlock(struct ttm_lock *lock)
 {
 	int ret = 0;