Re: Revert: ath: add support for special 0x0 regulatory domain

From: Peter Oh <peter.oh@eero.com>
To: Andrey Skvortsov <andrej.skvortzov@gmail.com>,
	linux-wireless@vger.kernel.org, ath10k@lists.infradead.org
Cc: "Wen Gong" <wgong@codeaurora.org>,
	"Kalle Valo" <kvalo@codeaurora.org>,
	"Alvin Šipraga" <alsi@bang-olufsen.dk>,
	"Brian Norris" <briannorris@chromium.org>,
	"Julian Calaby" <julian.calaby@gmail.com>, svp <svpm@yandex.ru>,
	felix+debian@gueux.org, "Massimo Maggi" <me@massimo-maggi.eu>
Subject: Re: Revert: ath: add support for special 0x0 regulatory domain
Date: Mon, 23 Aug 2021 11:15:58 -0700	[thread overview]
Message-ID: <15d3d071-61a2-0847-de13-634a0c2077d5@eero.com> (raw)
In-Reply-To: <YSJ//ki/A1EgfLga@skv.local>

On 8/22/21 9:49 AM, Andrey Skvortsov wrote:

> 1) Current behaviour maps 0x0 regulatory domain to the most restrictive
> world domain. According to the wiki (probably based on Atheros
> documentation) 0x0 means US. Does wiki contain wrong information?

0x0 means country section in OTP is not written yet and open to set to 
any country.

QCA sets to US in this case as a default value.

> 2) If I understand correctly, 0x0 is always replaced with 0x64 and that
> makes the following code useless, because it will never be executed. Is it
> ok?
>
> drivers/net/wireless/ath/regd.c:703:708
>
> if (reg->country_code == CTRY_DEFAULT &&
>          regdmn == CTRY_DEFAULT) {
>              printk(KERN_DEBUG "ath: EEPROM indicates default "
>                  "country code should be used\n");
>              reg->country_code = CTRY_UNITED_STATES;
> }
I don't think that's true. If you're seeing 0x0 is replaced with 0x64 
(CTRY_BULGARIA = 100), it could be because your device's manufacturer 
preconfigured country code with the value.
> 3) Previously it was possible to get regulatory information using 'iw reg
> get', but now it doesn't work anymore. Is it expected behavior?
>
> [--------------------4.19 ---------------------------------]
> # iw reg get
> global
> country 98: DFS-UNSET
> (2400 - 2483 @ 40), (N/A, 20), (N/A)
> (5150 - 5250 @ 100), (N/A, 20), (N/A), NO-OUTDOOR
> (5250 - 5350 @ 100), (N/A, 20), (0 ms), NO-OUTDOOR, DFS
> (5650 - 5730 @ 80), (N/A, 20), (0 ms), NO-OUTDOOR, DFS
> (5730 - 5850 @ 80), (N/A, 20), (N/A), NO-OUTDOOR
> (57240 - 66000 @ 2160), (N/A, 40), (N/A), NO-OUTDOOR
>
>
> [--------------------- 5.10 --------------------------------]
> #iw reg get
> global
> country RU: DFS-UNSET
> (2400 - 2483 @ 40), (N/A, 20), (N/A)
> (5150 - 5350 @ 160), (N/A, 20), (N/A), NO-OUTDOOR
> (5650 - 5850 @ 160), (N/A, 20), (N/A), NO-OUTDOOR
> (57000 - 66000 @ 2160), (N/A, 40), (N/A), NO-OUTDOOR
>
> [-----------------------------------------------------------]

The 4.19 output tells you that country code is changed to different one 
from manufacturer is set(US).

The 5.10 output seems manufacture set country code to RU. If it's the 
case, No phy level country code looks wrong or a bug.

Thanks,

Peter

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