AR9280 and noisy environments, please test

[Berislav Purgar]

On Thu, Nov 3, 2011 at 4:17 AM, Adrian Chadd <adrian.chadd at gmail.com> wrote:

> Hi all,
>
> I've added some local hacks to my if_ath_tx branch which hopefully
> will help us nail down what's going on with AR9280 and noisy
> environments.
>
> The theory: AR9220/AR9280 noise floor sampling is not picking up the
> bursty traffic that's going on in the air. so it's reporting a low NF
> but as the air spends most of its time with _some_ signal above what
> it thinks the NF is, it constantly thinks the channel isn't clear to
> TX. I saw this with AR9160 last year but it turned out to be issues
> with the AP power supply enclosure generating 2.4ghz spurs. I doubt
> we're seeing this here. :)
>
> The changes:
>
> * I've updated the ANI code a bit more, so it does some more "stuff"
> in hostap mode;
> * I've disabled OFDM weak detection by default in hostap mode, but I
> haven't (yet) disabled CCK weak threshold setting;
> * I've added some very rudimentary support to log how busy the channel
> is, so we can see what the difference is between different 11n NICs;
> * I've added a knob to allow the noise floor threshold (and thus the
> CCA threshold) to be manually set, rather than relying on sampling by
> the baseband.
>
> What I'd like you guys to try:
>
> * update if_ath_tx!
> * run the ar9280 in hostap or STA mode, it doesn't matter what, but
> enable NF and ANI debugging:
>  # sysctl dev.ath.X.hal.debug=0x28
> * let it run for a couple of minutes, so it gets a couple of NF
> calibrations (which occur every 30 seconds) and then report that to
> me.
>
> What you'll likely see is:
>
> * ANI goes bezerk with OFDM/CCK errors, and tries bumping up some
> things (spur immunity, firstep);
> * the NF values calibrated are either crazy looking (higher than -80),
> or chain 0 / chain 1 values are wildly mismatching;
>
> Then, try changing the longcal value from 30 to 1, and email me two or
> so minutes of logging output.
>
> Finally, set the CCA threshold to something manual, and rerun tests
> for a couple minutes:
>
> # sysctl dev.ath.X.config.cca=-85
>
> Thanks,
>
>
> Adrian
>

and results after executing sysctl dev.ath.1.hal.cca=-85

Beri
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