The latest ALSA update from swaret (0.98 and above i think) requires also the latest Kernel update frm swaret too.
I had the exact same problem, till i updates my kernel to 2.4.23, restarted, and all works perfectly again.
Either downgrade your ALSA to 0.96 (i think thats the version.. its the default one on a clean slack installation) with your Kernel 2.4.22, or update your kernel to 2.4.23 or even 2.4.24,
To update your kernel, there's no 'compiling' to do
just go to your /etc/swaret.conf file, and comment the
EXCLUDE kernel (by adding # in beginning of line)
and it should all work. (Dont hold me responsible for any kernel update problems tho... it worked perfectly for me.)
hope this helps