Am Dienstag, 17. November 2009 19:35:07 schrieb Eric W. Biederman:
> Boiled down. ftdi_chars_in_buffer is essentially
> priv->tx_outstanding_bytes. tx_outstanding_bytes is incremented when an
> urb request is sent and tx_outstanding_bytes is decremented when an urb
> request completes.
>
> It turns out I have a moderately noisy usb line, and so I occasionally
> get messages like:
>
> ehci_hcd 0000:00:0a.1: detected XactErr len 0/7 retry 31
>
> Which as best as I can tell result in the urb getting abandoned and
> neither completed nor canceled (because we have hit the maximum
> retry count and they still don't succeed).
The URB should be finished with an error code in urb->status.
ftdi_write_bulk_callback() does decrement the counter even in
the error case.
> Which appears to result in tx_outstanding_bytes getting stuck at
> some positive number.
Do you see this message
if (status) {
dbg("nonzero write bulk status received: %d", status);
return;
}
if you enable debugging output?
Regards
Oliver
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
