Sound Settings is missing all output devices

Question

Possible Duplicate:
My sound stopped working today, how can I fix it?

I'm baffled by this discrepancy:

1. This speaker test is successful:

   speaker-test -c 6 -D 'surround51:CARD=PCH,DEV=0'
   

2. Sound Settings is behaving as if I have no sound card:

   

How do I find out what's causing this problem?

Details

Have a look at aplay -L, pacmd list-cards, lshw, pulseaudio -vvvv, and pavucontrol. I do not use HDMI.

This discussion of a similar problem on a PulseAudio mailing list suggests that changes to /etc/pulse/default.pa might be responsible, but I have not edited this file.

Solution

Turns out I was running into Bug #590780: Installing "randomsound" package causes Pulseaudio to stop functioning at reboot and didn't know it yet. See this answer:

1. Run pstree | less
2. In that, type /arecord and press return to find the arecord process.
3. Press up once and you'll see its parent. In my case this was randomsound.

Comments

[RusGraf]

Which "sound settings" does this reset, and why do you recommend doing this? I'm not yet convinced that the problem is within ALSA, since it appears to detect my sound cards correctly.

[blackedx]

"Sound settings" corresponding to the image you linked above in your question. ALSA y detecting your sound card but isn't showing it in the "selec device" section. after this it should show it.