Comment 163 for bug 445852

In Karmic there is a new stable kernel 2.6.31-17.54
<https://bugs.launchpad.net/ubuntu/+source/linux/+bug/480144> that refer to
upstream kernel 2.6.31.6; in the changelog
<http://kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.31.6> is mentioned this
commit 9982364654c186acd48c3070dcf6a76c69e540cc with this description:

[quote]
commit 9982364654c186acd48c3070dcf6a76c69e540cc
Author: Tejun Heo <email address hidden>
Date: Fri Oct 16 13:00:51 2009 +0900

libata: fix internal command failure handling

commit f4b31db92d163df8a639f5a8c8633bdeb6e8432d upstream.

When an internal command fails, it should be failed directly without invoking
EH. In the original implemetation, this was accomplished by letting internal
command bypass failure handling in ata_qc_complete(). However, later changes
added post-successful-completion handling to that code path and the success
path is no longer adequate as internal command failure path. One of the
visible problems is that internal command failure due to timeout or other
freeze conditions would spuriously trigger WARN_ON_ONCE() in the success path.

This patch updates failure path such that internal command failure handling is
contained there.
[/quote]

Could be related to this bug?