I had the very same problem and backed out to kernel-2.6.32-71.29.1
while looking around for a solution. I found an ALSA kernel module on
atrpms.net and decided to give it a try. First I updated to
kernel-2.6.32-131.6.1.el6.x86_64 (I'm running 64-bit). which once
again killed my mic. Then I went up to atrpms.net and grabbed
alsa-kmdl-2.6.32-131.6.1.el6.x86_64-1.0.23-86.el6.x86_64 (look in
http://packages.atrpms.net/dist/el6/alsa-driver-1.0.23/). After
another reboot I found my mic worked again.
Phil Lembo
http://eldapo.lembobrothers.com