diff --git a/async.c b/async.c
index 332d511..ecdaf15 100644
--- a/async.c
+++ b/async.c
@@ -120,7 +120,7 @@
     bh->deleted = 1;
 }
 
-void qemu_bh_update_timeout(int *timeout)
+void qemu_bh_update_timeout(uint32_t *timeout)
 {
     QEMUBH *bh;