Re: Question about TX power

[Alexander Wilhelm <alexander.wilhelm@westermo.com>]

Am Thu, May 15, 2025 at 08:03:41PM +0200 schrieb Sebastian Gottschall:
> 
> Am 12.05.2025 um 10:51 schrieb Alexander Wilhelm:
> > Am Fri, May 09, 2025 at 03:49:55PM +0200 schrieb Sebastian Gottschall:
> > > 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?
> > I'm using QCN9074 chipset.
> okay. then we are at least talking about a common chipset i was talking
> about.
> whats the vendor and exact name of that device? i have some sorts of
> boardfiles from vendors collected.

I'm using Compex WLE3000HX for mPCIe. I've some sorts of boarfiles collected as
well. But my intention is to fully understand how antenna gain is encoded and
what do I need to request from the module manufacturer. For example I though
that antenna gain is only a constant value, but now I see it changes from
channel to channel. I also need to understand if the firmware uses TPC with
ath11k, then I could use higher transmission powers on TPC channels.

Best regards
Alexander Wilhelm