[ath9k-devel] [PATCH 5/5] ath9k: Fix TX IQ calibration for SoC chips

[Wojciech Dubowik <Wojciech.Dubowik@neratec.com>]

On 01/16/2014 12:19 PM, Sujith Manoharan wrote:
> Sujith Manoharan wrote:
>> We could fix this by checking if we are initializing the history for the operating
>> channel and waiting for NF-cal completion, but I am not sure if this needs
>> to be done. The window is really small and subsequent NF calibrations using
>> the ANI routine work properly.
> Also, this is a bad idea in general since NF calibration has to
> wait for the medium to become idle - problematic when there is heavy
> interference or general WLAN usage.
>
> Sujith
I guess I won't be able to reproduce bad scan results with wireless 
testing since I have
changed scan reporting to pure rssi in my openwrt compat.
In normal case you get a sum of rssi and noise floor and it will be 
correct i.e. when
NF is shifted by 14db so will be rssi.
So it's just my use case.

Anyway I have just solved the issue by applying calibrated noise floor 
values from eeprom
instead of nominal in nf_get functions and nf histogram. Now the rssi 
seems stable in my test
environment. I have just started testing but it looks promising.

I don't know whether it's worth changing it upstream since most of 
available ar9003 cards
I have seen are not noise floor calibrated. A bit bad becasue it could 
be used for spectral
scan as well to improve accuracy.

Wojtek