--- a/sys/dev/drm/drm_memory.c
+++ b/sys/dev/drm/drm_memory.c
@@ -75,8 +75,7 @@ EXPORT_SYMBOL(drm_legacy_ioremap_wc);
 void drm_legacy_ioremapfree(struct drm_local_map *map, struct drm_device *dev)
 {
 	if (!map->handle || !map->size)
 		return;
 
-	pmap_unmapdev((vm_offset_t) map->handle, map->size);
+	iounmap(map->handle);
 }
 EXPORT_SYMBOL(drm_legacy_ioremapfree);