Hard lockup during vif restart tests.

[Kalle Valo]

Michal Kazior <michal.kazior at tieto.com> writes:

>> Why do we reset the firmware/NIC when we admin down/up the
>> vif (when a single vif is active)?  Couldn't we just keep
>> the firmware active in this state and not risk lockup due
>> to reset?
>
> If you put down last interface mac80211 calls drv_stop(). There isn't
> any real need to keep the device up and running after that other than
> trying to workaround the reset issue. But then you need to deal with
> firmware quirks. I recall it could report Rx indications after all
> vdevs had been removed (and this is now also observable with 10.2
> during probing/bootup). It's just simpler to reboot firmware on
> drv_stop/start().

And there's the reliability issue. Being able to reset the firmware with
interface down/up sequency is pretty useful and AFAIK almost all
upstream drivers do that. And let's not forget power consumption either.

-- 
Kalle Valo