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Date: Wed, 23 May 2012 14:36:38 -0400
Message-ID: <CA+7oygeU+7LKp3q1_S1UUtjS8SFOthC_q54pQAGAhR1jBBzavw@mail.gmail.com> (sfid-20120523_203701_408983_CB87F86A)
Subject: Re: AR9280 reported signal strengths are flat (comparison with
 bcm4322 included)
From: George Nychis <gnychis@gmail.com>
To: Holger Schurig <holgerschurig@googlemail.com>
Cc: linux-wireless@vger.kernel.org
Content-Type: text/plain; charset=ISO-8859-1
Sender: linux-wireless-owner@vger.kernel.org

Might anyone else have some insight here? I've tried digging through
the code to see if AGC is not properly taken in to consideration
during the RSSI calculation, but I think this is done in the firmware
which is out of view of my eyes.

On Wed, May 16, 2012 at 11:36 PM, George Nychis <gnychis@gmail.com> wrote:
>
> Well, I believe that I forced ANI to be disabled and I still see this
> same behavior.
>
> To disable ANI on my AR9280, I added this to __ath9k_hw_init() in hw.c
> ?if (AR_SREV_9280(ah))
> ? ?ah->config.enable_ani = false;
>
> I believe this works because in ath9k_hw_post_init() I have checked
> that ah->config.enable_ani is set to false. ?Therefore,
> ath9k_hw_ani_setup() and ath9k_hw_ani_init() are never called.
>
> Unfortunately, I still see this same flat line trend without strong
> signal strengths near the device.
>
>
> On Wed, May 16, 2012 at 2:35 PM, George Nychis <gnychis@gmail.com> wrote:
> >
> > BTW- is ANI _not_ applied on broadcast traffic? ?I notice that
> > monitoring the signal strength of beacons does not show this behavior.
> > ?Maybe not applied for localization reasons?
> >
> > - George
> >
> >
> > On Wed, May 16, 2012 at 2:32 PM, George Nychis <gnychis@gmail.com>
> > wrote:
> > > Hi Holger,
> > >
> > > Thanks a bunch for your response! ?I had read about ANI before on the
> > > list, it would be interesting to know if this is the cause for this.
> > > It definitely seems plausible. I will dig around the ath9k code and
> > > see if I can narrow down this to the cause.
> > >
> > >
> > > On Wed, May 16, 2012 at 2:31 PM, George Nychis <gnychis@gmail.com>
> > > wrote:
> > >>
> > >> Hi Holger,
> > >>
> > >> Thanks a bunch for your response! ?I had read about ANI before on the
> > >> list, it would be interesting to know if this is the cause for this.
> > >> ?It
> > >> definitely seems plausible. I will dig around the ath9k code and see
> > >> if I
> > >> can narrow down this to the cause.
> > >>
> > >> - George
> > >>
> > >>
> > >> On Wed, May 16, 2012 at 2:08 AM, Holger Schurig
> > >> <holgerschurig@googlemail.com> wrote:
> > >>>
> > >>> This is probably due to ANI (adapative noise immunity). I think
> > >>> ath9k
> > >>> does too much here, in other words: it doesn't just kick in if there
> > >>> are too strong signals there. Instead it seems to always adjust the
> > >>> input attenuator, needed or not.
> > >>
> > >>