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
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