It sounds like this bug is fixed upstream in mainline. Can you now test the latest 3.13 upstream stable kernel: http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.13.11.4-trusty/
If that still has the bug, then we can perform a "Reverse" bisect to find what commit fixes this in mainline.
It sounds like this bug is fixed upstream in mainline. Can you now test the latest 3.13 upstream stable kernel: kernel. ubuntu. com/~kernel- ppa/mainline/ v3.13.11. 4-trusty/
http://
If that still has the bug, then we can perform a "Reverse" bisect to find what commit fixes this in mainline.