[regression] Tri-band AMD RZ608 (MediaTek MT7921K) has 6GHz band disabled in kernel 6.8 despite working in <=6.6

[Linux regression tracking (Thorsten Leemhuis)]

On 18.04.24 10:48, Linux regression tracking (Thorsten Leemhuis) wrote:
>
> mt7921 maintainers, I noticed a report about a regression in
> bugzilla.kernel.org related to your driver. As many (most?) kernel
> developers don't keep an eye on bugzilla, I decided to write this mail.
> To quote from https://bugzilla.kernel.org/show_bug.cgi?id=218731 :

FWIW, the reporter meanwhile confirmed that this happens with 6.9-rc6.
No bisection so far

Mt7921 maintainers, so you have any idea what might be wrong? Or is this
a situation along the lines of "uhhps, we screwed up somewhere (hardware
detection, regulatory stuff, ...) and had to fix this, which leads to this".

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
If I did something stupid, please tell me, as explained on that page.

#regzbot poke

>> On kernel 6.6.27-1-lts, running `iw list` shows that 6GHz channels are supported:>
>> [...]
>> Similarly, discovering and connecting to 6GHz APs works fine.
>>
>> However, in recent kernel 6.8.5, running `iw list` shows that 6GHz channels are disabled:
>>
>> [...]
>>
>> And scanning or connecting to 6GHz APs does not work. 
>>
>> There's nothing in `dmesg` that differs between boots of the two kernels. On 6.8.5, 6GHz band doesn't work like it did on previous kernels. 
>>
>> I can provide more logs or help debug the issue if needed.
> 
> See the ticket for more details. Note, you have to use bugzilla to reach
> the reporter, as I sadly[1] can not CCed them in mails like this.
> 
> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
> --
> Everything you wanna know about Linux kernel regression tracking:
> https://linux-regtracking.leemhuis.info/about/#tldr
> If I did something stupid, please tell me, as explained on that page.
> 
> [1] because bugzilla.kernel.org tells users upon registration their
> "email address will never be displayed to logged out users"
> 
> P.S.: let me use this mail to also add the report to the list of tracked
> regressions to ensure it's doesn't fall through the cracks:
> 
> #regzbot introduced: v6.6..v6.8.5
> #regzbot title: wifi drivers: mt7921: 6GHz band stopped working
> #regzbot from: AlexDeLorenzo.dev
> #regzbot duplicate: https://bugzilla.kernel.org/show_bug.cgi?id=218731
> #regzbot ignore-activity
> 
>