Comment 3 for bug 1837821

Looks like the same issue I'm having on Thinkpad X1 Carbon 7th Gen running Ubuntu 19.04.

Debug output here:
http://alsa-project.org/db/?f=5c09dfb7b0fc0ff5ad32c0576893316f5613d3a1

As well as the Mic not being detected, and therefore not available for use in any applications, there is an issue with the master audio volume being either full-on or muted. individual mixer controls still work, but the main volume control does nothing other than mute the audio.