Re: ath9k becon loss messages

From: Kalle Valo
Date: Mon Apr 06 2009 - 06:24:18 EST


Michael Buesch <mb@xxxxxxxxx> writes:

>> NetworkManager typically scans every 120 seconds and I can also trigger
>> the messages by a manual scan with iwlist. I did not dig any further but
>> the messages seem to appear right at the end of the scan. Tried with iwlagn
>> and both sw_scan and hw_scan.
>
> Yeah OK. While scanning it's expected to lose some frames.
>
> However, the driver should probably protect against this by using the
> scan notification callbacks. It could disable beacon-loss reporting
> while scanning.

That case is already covered. In sw_scan mac80211 will disable power
save and hence beacon filter is also disabled. With hw_scan the firmware
should be clever enough to not emit beacon loss events when scanning.

But ath9k nor iwlwifi don't support beacon filtering and this is a
problem in mac80211. We need to disable the beacon loss check in
mac80211, most probably by stopping the associated timer whenever
scanning.

--
Kalle Valo
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