On ubuntu 20.04 on a thinkpad T14 1st gen AMD, the microphone led on the internal keyboard is constantly on, no matter if the microphone is on or off, which becomes annoying when typing in dark environments.
alsamixer on the command line, select the second
sound card, and select “Off” for the
Mic Mute-LED. This
means, the LED is constantly turned off, which is still not ideal, but
so much better than constantly on.