Not just disabled, not appearing anywhere, audio widget, system settings, pulse audio control. It worked fine yesterday, but then I mucked about with alsamixer.
Another login, no problem, microphone appears and works fine.
In desperation, I looked for files that had changed since yesterday with find -newermt yesterday. There were lots of files in ~/.cache and ~/.config/pulse that had changed, so I cleared them. Logged out, back in, and the microphone is back.
Another login, no problem, microphone appears and works fine.
In desperation, I looked for files that had changed since yesterday with find -newermt yesterday. There were lots of files in ~/.cache and ~/.config/pulse that had changed, so I cleared them. Logged out, back in, and the microphone is back.