[PATCH v2 01/12] USB: serial: digi_acceleport: fix broken rx after throttle

[Johan Hovold <johan@kernel.org>]

If the port is closed while throttled, the read urb is never resubmitted
and the port will not receive any further data until the device is
reconnected (or the driver is rebound).

Clear the throttle flags and submit the urb if needed when opening the
port.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/digi_acceleport.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/usb/serial/digi_acceleport.c b/drivers/usb/serial/digi_acceleport.c
index 6899aebfd6ae..097769525ca4 100644
--- a/drivers/usb/serial/digi_acceleport.c
+++ b/drivers/usb/serial/digi_acceleport.c
@@ -1069,6 +1069,7 @@ static int digi_open(struct tty_struct *tty, struct usb_serial_port *port)
 	unsigned char buf[32];
 	struct digi_port *priv = usb_get_serial_port_data(port);
 	struct ktermios not_termios;
+	int throttled;
 
 	/* be sure the device is started up */
 	if (digi_startup_device(port->serial) != 0)
@@ -1096,6 +1097,21 @@ static int digi_open(struct tty_struct *tty, struct usb_serial_port *port)
 		not_termios.c_iflag = ~tty->termios.c_iflag;
 		digi_set_termios(tty, port, &not_termios);
 	}
+
+	spin_lock_irq(&priv->dp_port_lock);
+	throttled = priv->dp_throttle_restart;
+	priv->dp_throttled = 0;
+	priv->dp_throttle_restart = 0;
+	spin_unlock_irq(&priv->dp_port_lock);
+
+	if (throttled) {
+		ret = usb_submit_urb(port->read_urb, GFP_KERNEL);
+		if (ret) {
+			dev_err(&port->dev, "failed to submit read urb: %d\n", ret);
+			return ret;
+		}
+	}
+
 	return 0;
 }
 
-- 
2.53.0