Bug 216818 - The microphone mute led not working after linux 6
Summary: The microphone mute led not working after linux 6
Status: NEW
Alias: None
Product: Drivers
Classification: Unclassified
Component: Sound(ALSA) (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: Jaroslav Kysela
Depends on:
Reported: 2022-12-18 08:52 UTC by sonic82003
Modified: 2022-12-19 17:08 UTC (History)
1 user (show)

See Also:
Kernel Version: >= 6.0
Tree: Mainline
Regression: No


Description sonic82003 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.
Comment 1 Hans de Goede 2022-12-19 09:58:13 UTC
This is caused by a behavior change of the kernel code controlling the LED to only turn on the LED when all inputs, including e.g. the jack mic input are turned off in the alsa-mixer settings.

But most userspace code only turns the mic which it is actually using on/off when you hit the mic-mute hotkey.

Also see: https://bugzilla.redhat.com/show_bug.cgi?id=2134824

Which is the same bug.

There is a set of fixes available in the form of an alsa-ucm update which tells the kernel to ignore the state of the jack mic input restoring the old behavior:

Comment 2 Jaroslav Kysela 2022-12-19 17:08:25 UTC
The easy way is to ask your distro to update the UCM configuration to the recent one.

Note that all previous kernels have a bug which may cause that the microphone LED is not updated correctly with the sof-hda-dsp driver. Just plug something to the analog jack on your system and mute/unmute/mute the analog input. The microphone LED will follow those changes, too. So you cannot trust the state for the old kernels anyway.

Note You need to log in before you can comment on or make changes to this bug.