Re: Question about TX power

[Sebastian Gottschall <s.gottschall@dd-wrt.com>]

Am 09.05.2025 um 13:59 schrieb Alexander Wilhelm:
> Am Fri, May 09, 2025 at 12:54:47PM +0200 schrieb Sebastian Gottschall:
>> Am 09.05.2025 um 10:43 schrieb Alexander Wilhelm:
>>> Hello devs,
>>>
>>> I'd like to understand how TX power setting works on ath11k devices. For example
>>> when I'm using channel 36 for ETSI based regulatory domain, I can set up to 23
>>> dBm. But then I get only 20 dBm as a result. On different channels and/or
>>> regulatory domains I get different reductions. I tried to follow the source
>>> code. As far as I understood is that 'ath11k_mac_txpower_recalc' sets the
>>> correct values and 'ath11k_mac_op_get_txpower' return the different one.
>>>
>>> My question is where this reduction offset is encoded. Is it in the module's
>>> firmware or is it part of the boardfile? Thank you in advance.
>>>
>>>
>>> Best regards
>>> Alexander Wilhelm
>> the boardfile contains chipset specific calibration data which also defines
>> the hardware power limits (more specific data also included in the on board
>> calibration flash of the device or if its a router, in flash memory of the
>> router itself. in addition it includes a regulatory database which is used
>> by the firmware for managing the total power. you have also to consider that
>> the 23dbm are specified without antenna gain.
>> so if the antenna gain is 3 dbm, you get 20 dbm in total. this antenna gain
>> may again be specified in the boardfile.
>> so you will not find your answers in any sourcecode. its all encoded in
>> binary data.
>>
>> Sebastian
>>
> Alright, thank you Sebastian. Since I'm not using any calibration data on my
> router/AP device, all data come from the boardfile. I've also understood that
> the power limit reduction is related to antenna gain. I'll ask the radio module
> manufacturer to create another boardfile for me that matches the required
> antenna gain for my router/AP device.
my answer might be not accurate here. which chipset we are talking about 
for ath11k?
>
> Best regards
> Alexander Wilhelm
>