Re: [PATCH] mt76: handle protocol error to proper deinit rx_tasklet

[Stanislaw Gruszka <sgruszka@redhat.com>]

On Sat, Nov 24, 2018 at 10:25:52AM +0100, Lorenzo Bianconi wrote:
> > During removal of usb dongle, noticed many unhandled rx urb
> > below. This this patch, make it possible and early completion
> > of the rx tasklet.
> >
> > mt76x2u 1-3.4.3.1.2:1.0: rx urb failed: -71
> > mt76x2u 1-3.4.3.1.2:1.0: rx urb failed: -71
> > mt76x2u 1-3.4.3.1.2:1.0: rx urb failed: -71
> > mt76x2u 1-3.4.3.1.2:1.0: rx urb failed: -71

If problem here is just printing errors, I think we are ok. If problem
is some hung or infinity loop, it should be fixed.

> Hi Eduardo,
> 
> I think EPROTO is a more general error (it is not strictly related to
> device removal)
> and it could happen even during normal operation. In this case I guess we should
> reinsert the urb to usb-core.

Some (out of tree) usb host drivers returns EPROTO all the time
in some error conditions. On rt2x00 resubmitting urb resulted in
infinity loop:
https://marc.info/?t=153375128700002&r=1&w=2

Fix I proposed for that was counting EPROTO errors and 
mark device as removed if 10 of them happened in row:
https://marc.info/?l=linux-wireless&m=153441755529960&w=2

Thanks
Stanislaw