diff --git a/[refs] b/[refs]
index 4ac1924fb729..45e2d0e3d301 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 298b9e44be9592e94c0e69a5d3893cd11f5484fa
+refs/heads/master: c93f09402106f22601838ee2bb0d02bae934b5e5
diff --git a/trunk/drivers/net/caif/caif_serial.c b/trunk/drivers/net/caif/caif_serial.c
index 3502f607117f..c669ec37483b 100644
--- a/trunk/drivers/net/caif/caif_serial.c
+++ b/trunk/drivers/net/caif/caif_serial.c
@@ -312,6 +312,10 @@ static int ldisc_open(struct tty_struct *tty)
 	char name[64];
 	int result;
 
+	/* No write no play */
+	if (tty->ops->write == NULL)
+		return -EOPNOTSUPP;
+
 	sprintf(name, "cf%s", tty->name);
 	dev = alloc_netdev(sizeof(*ser), name, caifdev_setup);
 	ser = netdev_priv(dev);