diff --git a/drivers/gpu/drm/sis/sis_drv.c b/drivers/gpu/drm/sis/sis_drv.c
index 4383b74a3aa4..756f787b7143 100644
--- a/drivers/gpu/drm/sis/sis_drv.c
+++ b/drivers/gpu/drm/sis/sis_drv.c
@@ -94,7 +94,7 @@ static int sis_driver_open(struct drm_device *dev, struct drm_file *file)
 	return 0;
 }
 
-void sis_driver_postclose(struct drm_device *dev, struct drm_file *file)
+static void sis_driver_postclose(struct drm_device *dev, struct drm_file *file)
 {
 	struct sis_file_private *file_priv = file->driver_priv;