diff --git a/xmm7360.c b/xmm7360.c
index ccd149d..acc7fea 100644
--- a/xmm7360.c
+++ b/xmm7360.c
@@ -1272,7 +1272,7 @@ static int xmm7360_tty_write(struct tty_struct *tty,
 	return written;
 }
 
-static int xmm7360_tty_write_room(struct tty_struct *tty)
+static unsigned int xmm7360_tty_write_room(struct tty_struct *tty)
 {
 	struct queue_pair *qp = tty->driver_data;
 	if (!xmm7360_qp_can_write(qp))