It seems this problem first occured for me after I upgraded to kernel v2.6.20 from v2.6.19. Then since upgrading to v2.6.22 the hangs caused by alsasound have gotten much worse. Finally, I got fed up with it and just removed alsasound from the runlevel altogether. Surprisingly, sound still works without alsasound. I’m using the in-kernel drivers so things are already autoloaded by the kernel/udev. I set volume levels with amixer in /etc/conf.d/local.start and it just works. It seems for this setup alsasound is redundant.