Re: [regression] Bug 216753 - 6e 6 ghz bands are disabled since 5.16 on intel ax211

[Coelho, Luciano]

On Thu, 2022-12-01 at 11:14 +0100, Thorsten Leemhuis wrote:
> Hi, this is your Linux kernel regression tracker.
> 
> Luca, I noticed a regression report in bugzilla where I'd like your
> advice on. To quote https://bugzilla.kernel.org/show_bug.cgi?id=216753

Hi Thorsten wearing-the-regression-hat, 🙂

I'm not the maintainer of iwlwifi anymore, so I'm adding the new
maintainer here, Gregory Greenman.

Gregory, can you take a look?


> > It looks like the self-managed regulatory information is causing the 6ghz band to be disabled on my AX211 (in the US).  
> > iw reg get shows no 6ghz bands (output at the bottom).
> > 
> > $ sudo iw phy0 channel 
> > ...
> > Band 4:
> > 	* 5955 MHz [1] (disabled)
> > 	* 5975 MHz [5] (disabled)
> > 	* 5995 MHz [9] (disabled)
> >         ....(continues with all disabled 
> >         * 7115 MHz [233] (disabled)
> > ...
> > 
> > I was able to narrow this down to having been introduced during the 5.16 development window, as 5.15.79 linux-stable kernel works and the 5.16.12 does 
> > not (earlier builds of 5.16 kernel fail to boot on my machine for some reason). 
> > 
> > I found https://community.frame.work/t/kernel-5-16-6ghz-disabled-ax210/15675/5
> > and they imply that this regression was introduced by 
> > 698b166ed3464e1604a0e6a3e23cc1b529a5adc1
> > I haven't independently verified this commit as the definitive issue.
> 
> You authored 698b166ed346 ("iwlwifi: mvm: read 6E enablement flags from
> DSM and pass to FW"). As it is a regressions is ideally should be dealt
> with. But this area in tricky due to the legal implications. Hence I
> wonder: is there anything we can do about this, or is this simply a case
> where we have to bite the bullet and live with this regression?
> 
> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
> 
> P.S.: As the Linux kernel's regression tracker I deal with a lot of
> reports and sometimes miss something important when writing mails like
> this. If that's the case here, don't hesitate to tell me in a public
> reply, it's in everyone's interest to set the public record straight.