Hello.

>> On Tue, 19 Feb 2002 15:40:00 -0500 (EST)
 Nathan Langford <nathanl@remus.rutgers.edu> wrote:

 > I have been struggling with audio problems on my Thinkpad a20m.  I am
 > unable to play mpeg or midi files on the Cirrus Logic sound card.  CDs
 > work fine, but everything else produces a dull grinding sound.

This seems ACPI problem(kern/12843). Have you tried to turn off 
"PCI BUS Power management" in BIOS ?

Tacha