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

[Dave Chiluk]

The other possibility is that this is actually a bios bug, as the DSM
is being read out of ACPI.  In which case that would be Dell's fault.
Either way I appreciate any guidance you can provide.

Thanks,
Dave.


On Thu, Dec 1, 2022 at 5:33 AM Coelho, Luciano <luciano.coelho@xxxxxxxxx> wrote:
>
> 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.