Comment 12 for bug 315971

This turned out to be the root cause of a sound issue I was having. After updating to latest jaunty this morning and manually re-adding "options snd-hda-intel model=mitac" to enable my 82801H [8086:284b] audio chip (bug #210865), I found that alsa had re-muted my Front and other channels.

On reboot sound acted as if it were muted, but I was quite confused that alsamixer showed only a single channel, unmuted and at full volume. (My System/Preferences/Sound applet is missing and I've no idea what happened to it, but that's a separate issue).

I found by killing pulseaudio, I could unmute in alsamixer, restart pulseaudio, and everything worked again. I also tested using alsamixer -c 0 and believe that should do it too.

alsamixer -c 0 is nice to learn about and something I'll definitely keep in my back pocket for future troubleshooting. However, this doesn't seem to be a very discoverable solution to this problem.