Comment 12 for bug 965213

I am seeing similar symptoms.
With a Sony "Y Series" laptop (containing an AMD/ATI SBx00 SATA interface), whenever AC power is removed I see similar messages in dmesg.

There are no issues at all under AC power, only when operating on battery. The issue is present whether booting under battery power or booting under AC and then switching to battery.

I suspect it may be a pm-utils or kernel regression (based on similar bugs reported circa 2010).

The issue was not present with Ubuntu or XUbuntu 11.10 however is present in both Ubuntu and XUbuntu 12.04.
I have tried using 12.04 beta 2 and daily (as of 16/04/2012).
I have also tried using the most recent mainline kernel and still experienced the issue.

I will attach detailed logs once I have access to the machine again.