James Cameron <qu...@laptop.org> writes:
> On Wed, Feb 14, 2018 at 04:26:42PM +0000, Jean Pierre TOSONI wrote:
>> ath9k returns a wrong RSSI value for frames received in a 30ms time
>> window after a channel change. The correct value is typically 10dB
>> below the returned value.
> How was your correct value determined?
>> This was found with a Atheros AR9300 Rev:3 chip (WLE350NX / JWX6083
>> cards), during offchannel scans.
>> Mark the signal value as invalid in this case.
> Why not adjust by 10dB?
> Speculating: in a typical card, RSSI is calculated by firmware from
> readings of ADCs attached to the receiver. Firmware may average
> several readings. Firmware may apply other offsets or calibrations,
> based on frequency and temperature. This sounds like a firmware
ath9k does not have firmware, only ath9k_htc has it.