Comment 20 for bug 587786

Upgraded alsa 1.0.21 to 1.0.23 following these instructions

http://monespaceperso.org/blog-en/2010/05/02/upgrade-alsa-1-0-23-on-ubuntu-lucid-lynx-10-04/

and speaker started working.

So it looks like the fix is to include the latest version of alsa in 10.4lts