linux-backports-modules-alsa-2.6.31-21-generic 2.6.31-21.23 (i386 binary) in ubuntu karmic

 This package contains modules supplied by Ubuntu for Linux 2.6.31 ALSA
 snapshots from http://www.alsa-project.org/main/index.php/Main_Page
 .
 You likely do not want to install this package directly. Instead, install
 the linux-backports-modules-alsa-generic meta-package, which will ensure that upgrades work
 correctly, and that supporting packages are also installed.