* This routine notifies the tty driver that it should stop
* outputting characters to the tty device.
*
+ * Called with ->flow_lock held. Serialized with start() method.
+ *
* Optional:
*
* Note: Call stop_tty not this method.
* This routine notifies the tty driver that it resume sending
* characters to the tty device.
*
+ * Called with ->flow_lock held. Serialized with stop() method.
+ *
* Optional:
*
* Note: Call start_tty not this method.