int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
size_t size);
/* May be used by hardware driver to gain control over HDLC device */
-void detach_hdlc_protocol(struct net_device *dev);
+int detach_hdlc_protocol(struct net_device *dev);
static __inline__ __be16 hdlc_type_trans(struct sk_buff *skb,
struct net_device *dev)