I found a serious bug in the 3.1 kernel series. It is a major regression.
I also tested the situation with today's snapshot with the same result.
I already reported at two places, but i am not sure if it was the right place:
https://bugzilla.kernel.org/show_bug.cgi?id=41972
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/837995
Also it behaves the same if I compile the kernel myself and not use
the Ubuntu packages.
Thanks, Alan