If you are on ubuntu hardy I feel your pain. It completely blows. Perhaps this will help, the result of many many painful hours combing the forums. It seems to do the trick for me, anyway. I programmed this as a bash shortcut so I wouldn't forget.
I don't really know what the fix is when things crap out, I have just kind of tried things blindly.
http://ubuntuforums.org/archive/index.php/t-968697.html
(?) sudo alsa reload
sudo alsa force-reload
also: look for a dialog that pops up, possibly in task bar, if it asks if reload is ok, it is. beh.
also related
https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/294859
also suggested:
sudo killall pulseaudio
sudo alsa force-reload
also:
rm /var/lib/alsa/asound.state (don't include the rm if googling for this post)
sudo force alsa-reload
http://74.125.77.132/search?q=cache:faaeSQtYS4cJ:pennsylvania.ubuntuforums.com/showthread.php%3Fp%3D6242032+gvfs+alsa&hl=en&ct=clnk&cd=5&gl=pl
Is there a new trick for making these wide comments not screw up the page width? The last trick users suggested stopped working in FF4, apparently. What is the latest?
Yeah. Ubuntu marketing says, We make Linux Easy. And mostly this is true. But here, they opted for using the latest and greatest technology (pulse) rather than old and known to work everywhere (alsa) because of developer pressure, in a supposedly LTS version that huge numbers of people are going to use.
I view this is one of the greatest, if not the greatest, ubuntu screwup.