Linux ALSA driver
This device isn't supported by current Alsa Driver  (as of May 25, 2007).
However, Takashi Iwai has added support to this device in Alsa development version ... Still have to wait to get it included in the Linux Kernel... Note: It is rather trivial too get this working in a standard kernel right now, It is only 3 patches on top of the stock 1.0.14 code:
Alsa-Driver 1.0.14 added some support for this chip, but did not work on my T61; however, using the latest HG/Mercurial makes everything work. I created a Debian package for unstable/sid with the HG alsa that works for me, available at . --Jello 15:31, 6 July 2007 (UTC)
Works with Kernel 2.6.22 and Alsa 1.0.14a --Schlodty 12:01, 21 July 2007 (UTC)
Did not get it to work on X61s with either of the above packages. Newer HG packages do support this chip, so alsa 1.0.15 should have full support for this chip. --hjh 9:09, 27 July 2007 (UTC)
Works with a patched 220.127.116.11 kernel using the 2007/07/20 patch from ftp://ftp.alsa-project.org/pub/kernel-patches/ . Just make sure that you have the PCM channel unmuted and the speaker switch checked.