Merge tag 'mfd-3.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-2.6

[cascardo/linux.git] / drivers / usb / serial / usb-serial.c

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 0a17f59..a19ed74 100644 (file)
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -694,10 +694,20 @@ static int serial_carrier_raised(struct tty_port *port)
 static void serial_dtr_rts(struct tty_port *port, int on)
 {
        struct usb_serial_port *p = container_of(port, struct usb_serial_port, port);
-       struct usb_serial_driver *drv = p->serial->type;
+       struct usb_serial *serial = p->serial;
+       struct usb_serial_driver *drv = serial->type;
 
-       if (drv->dtr_rts)
+       if (!drv->dtr_rts)
+               return;
+       /*
+        * Work-around bug in the tty-layer which can result in dtr_rts
+        * being called after a disconnect (and tty_unregister_device
+        * has returned). Remove once bug has been squashed.
+        */
+       mutex_lock(&serial->disc_mutex);
+       if (!serial->disconnected)
                drv->dtr_rts(p, on);
+       mutex_unlock(&serial->disc_mutex);
 }
 
 static const struct tty_port_operations serial_port_ops = {