I have a fresh install of Ubuntu 9.04, Jaunty on a Lenovo T60 and since the beginning sound was muted after login. The drum roll happen at the GDM login screen but no login sound. Yesterday I eventually found a solution for it.
The solution was comment out line 372 in /etc/init.d/alsa-utils. The line in question was ‘mute_and_zero_levels “$TARGET_CARD” || EXITSTATUS=1’. Just this small change has solved the issue for me.
Now to be honest, I have no idea what the purpose of this line is and whether any other issues might crop up by commenting out this line. Well, sofar I have found no regressions by commenting out the line.