Comment 60 for bug 763688

Thanks @Angel Garcia, that did the trick. Just in case it helps anyone, mine was a fresh install of 11.04 not an upgrade so I followed the instructions at http://www.ramoonus.nl/2010/05/linux-kernel-2-6-34-installation-guide-for-ubuntu-linux-10-04/ to change the kernel - after changing the boot order to the old kernel, the bug was gone.