Comment 6 for bug 988268

Status:

I just erased & re burnt the 2012.04 Ubuntu release on snowball. After console booted, just executed, aplay -Dhw:0,1 xyz.wav. This worked perfectly giving audio output via AUDIO OUT jack. This shows, that, the audio driver and kernel works fine. And this is not a regression, as this basic command was not working earlier, due to some improper configurations.

From the user space, as mentioned by Abhishek, if test sound is invoked via sound settings, the audio output is not heard & any audio from ubuntu userspace is not heard. This may be because, of pulseaudio. Userspace directly uses pulseaudio & pulseaudio uses alsa. Since we have many unfixed issues with pulse-audio, like choppy playback, i think the pulse-audio should never be enabled/included in our releases by default, until it is fixed properly(Also, the pulse-audio's choppy playback, is faced by many in other platforms too, apart from snowball). Since in latest ubuntu distribution there are some applications and applets which directly uses pulse-audio by default (like volume indicator, & gstreamer), these should be replaced, with alsa volume control, gnome-alsa mixer from older ubuntu distributions and the userspace should try to use direct ALSA instead of pulse-audio by default. The below, link, gives some info on what packages/user space libraries need to updated to have direct ALSA working.. instead of using pulse-audio.
http://www.jeffsplace.net/node/12 (Not yet tested in snowball)

May be we need to customize our ubuntu distribution for snowball, which uses Direct ALSA by default to fix this issue.