diff --git a/drivers/gpu/drm/sis/sis_mm.c b/drivers/gpu/drm/sis/sis_mm.c
index c4debfdc1aaad06c7a0025d5b401ae5faf8c1324..af22111397d8cad6822cfa1b659c291ec885fa45 100644
--- a/drivers/gpu/drm/sis/sis_mm.c
+++ b/drivers/gpu/drm/sis/sis_mm.c
@@ -57,7 +57,7 @@ static void *sis_sman_mm_allocate(void *private, unsigned long size,
 	if (req.size == 0)
 		return NULL;
 	else
-		return (void *)~req.offset;
+		return (void *)(unsigned long)~req.offset;
 }
 
 static void sis_sman_mm_free(void *private, void *ref)