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Commit b0cda8c5 authored by Elina Pasheva's avatar Elina Pasheva Committed by Greg Kroah-Hartman
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USB: serial: sierra driver read path bug fix 



This patch fixes a problem in function sierra_indat_callback() which
would stop receiving traffic from a modem if a number of URB failures
occur.  Failed URBs are not resubmitted for the next read and there is
only a limited number of URBs allocated for the IN path. After this
number of failures, the receive path stops working on a particular
interface.

Signed-off-by: default avatarElina Pasheva <epasheva@sierrawireless.com>
parent 40d2ff32

drivers/usb/serial/sierra.c

+17 −11
Original line number Diff line number Diff line
@@ -509,24 +509,30 @@ static void sierra_indat_callback(struct urb *urb) 
	unsigned char *data = urb->transfer_buffer;

	int status = urb->status;



	dbg("%s: %p", __func__, urb);



	endpoint = usb_pipeendpoint(urb->pipe);

	port = urb->context;



	dev_dbg(&port->dev, "%s: %p\n", __func__, urb);



	if (status) {

		dev_dbg(&port->dev, "%s: nonzero status: %d on"

			" endpoint %02x\n", __func__, status, endpoint);

	} else {

		if (urb->actual_length) {

			tty = tty_port_tty_get(&port->port);



			tty_buffer_request_room(tty, urb->actual_length);

			tty_insert_flip_string(tty, data, urb->actual_length);

			tty_flip_buffer_push(tty);



			tty_kref_put(tty);

		} else

			usb_serial_debug_data(debug, &port->dev, __func__,

				urb->actual_length, data);

		} else {

			dev_dbg(&port->dev, "%s: empty read urb"

				" received\n", __func__);

		}

	}



	/* Resubmit urb so we continue receiving */

	if (port->port.count && status != -ESHUTDOWN && status != -EPERM) {
@@ -535,7 +541,7 @@ static void sierra_indat_callback(struct urb *urb) 
			dev_err(&port->dev, "resubmit read urb failed."

				"(%d)\n", err);

	}

	}



	return;

}