Changed package - this is more likely issue in kernel. Can you check if headphones work and the issue is only with speakers? This would be very similar as bug 94036.
** Changed in: linux-source-2.6.20 (Ubuntu) Sourcepackagename: acpi-support => linux-source-2.6.20 -- No sound after resuming from hibernation https://launchpad.net/bugs/96230 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
