From 555127652646d63c517b515f7c3edc5ced5b5888 Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Wed, 7 Apr 2010 16:49:31 -0700
Subject: [PATCH] --- yaml --- r: 193993 b: refs/heads/master c:
 c93f09402106f22601838ee2bb0d02bae934b5e5 h: refs/heads/master i:   193991:
 65c7b417816efdf28dbcbdccf5fc10163e860b63 v: v3

---
 [refs]                               | 2 +-
 trunk/drivers/net/caif/caif_serial.c | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

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);