USB: serial: ti_usb_3410_5052: Avoid goto in bulk in callback

[Ladislav Michl <ladis@linux-mips.org>]

On Mon, Dec 11, 2017 at 12:52:46PM +0100, Johan Hovold wrote:
> On Mon, Dec 11, 2017 at 12:32:49PM +0100, Ladislav Michl wrote:
> > On Mon, Dec 11, 2017 at 11:10:35AM +0100, Johan Hovold wrote:
[snip]
> > > I'm afraid I don't consider this an improvement. I prefer using gotos
> > > for error paths, while keeping the success path out of the status
> > > switch.
> > > 
> > > Furthermore, this isn't functionally equivalent as we'd not longer log
> > > an error for -EPIPE.
> > 
> > Yes, you are right... Now, shouldn't we react somehow to stalled endpoint?
> > Tty side seems to be unaware of it.
> 
> Recovering from a stalled endpoint is a bit involved, so for now we
> typically just log an error an bail out (forcing the user to reopen the
> port). This seems to work well enough as this condition should be rare.

I just do not see this in code. I would expect pending tty I/O operation
would fail once USB device errors out with -EPIPE, so tty side consumer gets
notified about error. Either it is not there or I did not look hard enough :)

> > > In fact, that -EPIPE is already on my TODO list as we really should not
> > > be resubmitting URBs for a stalled endpoint in the first place. That in
> > > turn should allow for some clean up of this callback.
> > 
> > Out of curiosity, how would be stalled endpoint reported?
> 
> Simply logging that the urb has been stopped along with the URB status
> (-EPIPE) should be enough.

See above.

> Johan

Best regards,
	ladis
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