Re: [PATCH 11/13] wcn36xx: Do not suspend if scan in progress

[Kalle Valo <kvalo@codeaurora.org>]

Bryan O'Donoghue <bryan.odonoghue@linaro.org> writes:

> On 11/01/2021 11:31, Kalle Valo wrote:
>> Bryan O'Donoghue <bryan.odonoghue@linaro.org> writes:
>>
>>> If a scan is in progress do not attempt to enter into suspend. Allow the
>>> scan process to quiesce before proceeding.
>>>
>>> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
>>
>> Why? I would have considered the opposite and if we go to suspend we
>> cancel the scan. No strong feelings, just don't see the need for scan
>> results during suspend. But of course I might be missing something...
>
> We need to be switched to the AP's channel when calling the suspend
> routine. During a s/w scan we switch off channel to scan for 100s of
> milliseconds.
>
> If the suspend() routine is called while that is true, we suspend on
> the wrong channel.
>
> So we would need to switch to the right channel explicitly in suspend
> but, at the moment wcn36xx_config() for switching channels and I
> thought it best to leave the channel switching logic in the one place.
>
> I'm not opposed in principle to
>
> - Entering suspend
> - Switching to the last known active channel
> - Suspending

Should this be fixed in mac80211? Otherwise every driver using software
scan needs to have a workaround for this, right?

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