USB: serial: add modem-status-change wait queue

Add modem-status-change wait queue to struct usb_serial_port that subdrivers can use to implement TIOCMIWAIT. Currently subdrivers use a private wait queue which may have been released when waking up after device disconnected. Note that we're adding a new wait queue rather than reusing the tty-port one as we do not want to get woken up at hangup (yet). Cc: stable <[email protected]> Signed-off-by: Johan Hovold <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
rtvt123 · Mar 21, 2013 · e5b33dc · e5b33dc
1 parent d797105
commit e5b33dc
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
@@ -66,6 +66,7 @@
  *	port.
  * @flags: usb serial port flags
  * @write_wait: a wait_queue_head_t used by the port.
+ * @delta_msr_wait: modem-status-change wait queue
  * @work: work queue entry for the line discipline waking up.
  * @throttled: nonzero if the read urb is inactive to throttle the device
  * @throttle_req: nonzero if the tty wants to throttle us
@@ -112,6 +113,7 @@ struct usb_serial_port {
 
 	unsigned long		flags;
 	wait_queue_head_t	write_wait;
+	wait_queue_head_t	delta_msr_wait;
 	struct work_struct	work;
 	char			throttled;
 	char			throttle_req;