I have the same (similar?) problem on my Thinkpad T42. No sound after hibernate. To get sound back I need to shut laptop down and start it back up. Reboot does not help - looks like laptop has to be powered down to reset something. Suspend to RAM does not kill sound. On the same laptop both suspend and hibernate work without any issues with Dapper - have it on another partition. There is nothing suspicious in dmesg; rhythmbox/totem/aplay act as they are playing fine. There is just no sound coming from speakers or headphones.
00:1f.5 Multimedia audio controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev 01) -- [Feisty] Inaudible audio upon resuming from suspend-to-disk https://launchpad.net/bugs/80893 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
