[ath9k-devel] How to get CSI from Atheros Chipset

[Till Wollenberg <till.wollenberg@uni-rostock.de>]

Hi Adrian,

* On 24.08.2015 18:40 Adrian Chadd wrote:
> On 24 August 2015 at 08:14, Till Wollenberg <till.wollenberg@uni-rostock.de> wrote:
>> * On 23.08.2015 at 21:57 Adrian Chadd wrote:
>>> [Getting CSI]
>>> ok, I've found a few pieces about this. What exactly are people after?
>>
>> SNR per OFDM sub-carrier for a recevied frame would be *very* interesting to me.

> ok,
>
> So the legacy bits include |I| and |Q| but it's not per-frame, it's
> set-once-and-get-next-frame. You then read bins from the NIC itself in
> some shared memory inside said NIC. I'll go see if this works on the
> earlier chips and try to get this published, at least so there's
> something to start with.

Sounds interesting. So is this per-frame information if the internal registers 
are read out right after receiving a frame, or is it always an aggregate over 
several received frames?

> I think AR9380 and later support what you saw in that paper - where
> you request that you get CSI data as part of some receive frame. I
> /think/ it's part of the TxBF support. I'll have to double-check if
> that's okay to extract and publish.

I'm not the OP so I'm not quite sure what the paper is about. Nevertheless, I 
plan to use AR9590 and/or AR9390 cards so I guess that these meet the criterion 
of "AR9380 and later".

Best
Till.