Subject: [PATCH 002/002] USB: serial: sierra driver read path
bug fix
From: Elina Pasheva <epasheva@xxxxxxxxxxxxxxxxxx>
The following is summary of changes we have made to sierra.c driver in
[PATCH 002/002] dealing with read path bug fix:
- Fixed 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: Elina Pasheva <epasheva@xxxxxxxxxxxxxxxxxx>
---
drivers/usb/serial/sierra.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
--- a/drivers/usb/serial/sierra.c 2009-04-28 18:27:53.000000000 -0700
+++ b/drivers/usb/serial/sierra.c 2009-04-28 19:05:59.000000000 -0700
@@ -460,33 +460,39 @@ static void sierra_indat_callback(struct
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) {
- err = usb_submit_urb(urb, GFP_ATOMIC);
- if (err)
- dev_err(&port->dev, "resubmit read urb failed."
- "(%d)\n", err);
}
}
+
+ /* Resubmit urb so we continue receiving */
+ if (port->port.count && status != -ESHUTDOWN && status != -ENOENT) {
+ err = usb_submit_urb(urb, GFP_ATOMIC);
+ if (err)
+ dev_err(&port->dev, "resubmit read urb failed."
+ "(%d)\n", err);
+ }
+
return;
}
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