Comment 36 for bug 446164

David,
  is there any reason you believe your freezes are related to this bug? I ask because it is important to open another bug if it turns out your problems aren't this bug, so that it can be properly tracked.

  After you experience the freeze can you run
    apport-collect -p linux 446164

  Also there is a test kernel which may fix this bug at
http://kernel.ubuntu.com/~jj/linux-image-2.6.31-15-generic_2.6.31-15.50~jj_amd64.deb