I have a friend who had big trouble with his Via laptop soundcard. It turned out that he needed a patch for it because it was a bug in the OSS driver. (This was in 2.4.18) so if you have some spare time, you might want to try 2.4.19-rc1 (?) and see if that works. I'm still using OSS here with my SB Live but eventually I might get around to using the ALSA support in the 2.5.x series