Comment 17 for bug 500999

That looks like a much more likely commit to fix this. Did you double-check by testing the last freezing (i.e. "good") and first non-freezing (i.e. "bad") kernel again?

It seems that the commit is not as atomic as it maybe should have been, since it fixes a bug and changes the behaviour. I will leave it up to the Ubuntu developers to assess whether the commit can be appled as a whole or needs to be rewritten. Anyway, they should now have all the information they need in order to fix this. Thank you for excellent troubleshooting!