I can confirm that v3.19 final: http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.19-vivid/ does not show the problem
4.0-rc1: http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.0-rc1-vivid/ and http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.2-unstable/ both do show the problem
I can confirm that kernel. ubuntu. com/~kernel- ppa/mainline/ v3.19-vivid/ does not show the problem
v3.19 final: http://
4.0-rc1: http:// kernel. ubuntu. com/~kernel- ppa/mainline/ v4.0-rc1- vivid/ kernel. ubuntu. com/~kernel- ppa/mainline/ v4.2-unstable/
and
http://
both do show the problem