Comment 163 for bug 290153

There is a commit related to link init failures in the final karmic kernel which may be relevant. So it may be worth testing with 2.6.31-14.46:

  commit e827d71dd6d39b3e28a519cb0bace9634d42aa7d
  Author: Tejun Heo <email address hidden>
  Date: Tue Oct 6 17:08:40 2009 +0900

    libata: fix incorrect link online check during probe

    commit 3b761d3d437cffcaf160a5d37eb6b3b186e491d5 upstream.

    While trying to work around spurious detection retries for
    non-existent devices on slave links, commit
    816ab89782ac139a8b65147cca990822bb7e8675 incorrectly added link
    offline check logic before ata_eh_thaw() was called. This means that
    if an occupied link goes down briefly at the time that offline check
    was performed, device class will be cleared to ATA_DEV_NONE and libata
    wouldn't retry thus failing detection of the device.