v4.13 on nokia n900: oops during tethering

[Pavel Machek]

Hi!

> > During tethering, I got oops in ssi_stop_tx(), followed by failure of
> > GPRS. I used GPRS tethering a lot with some older kernel, and it was
> > stable for hours.
> > 
> > It seems v4.12 has the same problem. In v4.15 usb networking does not
> > work at all, so I can't test... v4.10 seems to have similar problem. (Testing is
> > slighlty tricky, as my internet connection is ... tethering using
> > N900.)
> 
> Based on a quick look ssi_stop_tx() is called too many times (i.e. once
> more than ssi_start_tx()). This would appear to be an interal problem
> with the SSI codebase (or whatever lies there; I don't know the current
> codebase).

If you had ideas for debugging patch or maybe a workaround, that would
be nice...

> Did this work in the past? When? There appear to have been changes in IRQ
> handling some time in 2016...

I could not find working version. It looks like it really depends on
workload... tethering over USB triggers it quickly, but apparently
only if I generate "right" ammount of network load.

There were also some power management changes....

GPRS traffic generated from N900 does not seem to trigger the problem,
or not easily.

Best regards,
									Pavel
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