[regression] Bug 216818 - The microphone mute led not working after linux 6

[Thorsten Leemhuis]

Hi, this is your Linux kernel regression tracker speaking.

I noticed a regression report in bugzilla.kernel.org. As many (most?)
kernel developer don't keep an eye on it, I decided to forward it by
mail. Quoting from https://bugzilla.kernel.org/show_bug.cgi?id=216818 :

>  sonic82003@xxxxxxxxx 2022-12-18 08:52:32 UTC
> 
> The mic mute led of my ThinkPad X1 Carbon Gen 9 doesn't work anymore after updating linux to version 6.
> I can still turn it on by  running 
> 
> echo 1 > /sys/class/leds/platform::micmute/brightness
> 
> With linux-lts it still works fine.

See the ticket for more details.

Note, I found a similar report that (despite my attempts to prevent
things like this from happening) fell through the cracks here:
https://bugzilla.kernel.org/show_bug.cgi?id=216355

>  plum 2022-08-13 02:11:01 UTC
> 
> I upgrade to kernel 5.19.1 but found my thinkpad x1 carbon 2021's mute led stop working.
> 
> Function is okay but LED won't light up.
> 
> Back to kernel 5.18 and it's normal and working again.
> 
> Fedora 36 64 bit 
> Gnome-shell 42

>From a quick research it looks to me like this is an issue for the
sounds maintainers, as the LED itself apparently works. If that is
something for the platform people instead please speak up.

BTW, 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: v5.18..v5.19
https://bugzilla.kernel.org/show_bug.cgi?id=216818
#regzbot ignore-activity

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.