[ath9k-devel] Spectral Scan in ath9k

[Claudio <rossi.claudio.82@gmail.com>]

Alex Hacker <hacker <at> epn.ru> writes:

> 
> On Thu, May 31, 2012 at 12:19:08PM -0700, Adrian Chadd wrote:
> > Argh, there's more to it.. 
> > 
> > For AR9160 and later, you can enable the FFT bit in one of the radar
> > registers and you'll get some FFT reports for longer radar pulses.
> > It's enabled by default in the code that we've committed to ath9k and
> > FreeBSD HAL.
> > 
> > Spectral scan mode is related but different (and not in AR9160.)
> > 
> > So for longer pulses, you'll get RADAR payload (phyerr code = 5) which
> > may just have the pri/ext pulse duration and some config info, or it
> > may have a series of FFT reports first. That's just for radar stuff
> > though, it's not spectral scan.
> > 
> > That's why he mentioned code = 5 or code = 38.
> > 
> > 
> > Adrian
> 
> Hi Adrian.
> Yes, I'm thinking same way. You right, some additional information 
required.
> But for guys who have an interest and time to do some reverse engineering 
we
> give a starting point. :) Just another more clear hint for them. Look into
> published DFS code (it's low level part) and HW radar filter parameters in
> AR_PHY_RADAR_* registers.
> 
> Best regards to you,
> Alex.
> 

Hi all,
 first of all thank you for the code you have developed.
I have tried to use it but at each time outputs a different number of FFT 
samples.

I am using FFT_eval (https://github.com/simonwunderlich/FFT_eval) and the 
following commands:


echo chanscan > /sys/kernel/debug/ieee80211/phy0/ath9k/spectral_scan_ctl
iw dev wlan0 scan
cat /sys/kernel/debug/ieee80211/phy0/ath9k/spectral_scan0 > /tmp/fft_resusts
./fft_eval /tmp/fft_results 

On average I get 200-400 samples but sometimes I got even 7k samples, which 
is very good.

I was wondering what causes such variability on how (if possible) perform 
the spectral scan obtaining a high and constant sample set.

I am not touching the other parameters and I am using compat-drivers-3.9-
rc4-2-s

Thank you

Claudio