The 3.13.2 kernel was also just recently released. Can you give that one a test, to see if the fix from 3.14-rc1 made it to stable already? If not, we can bisect:
http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.13.2-trusty/ -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1276037 Title: [Thinkpad T420s] Brightness dims when unplugging external monitor and cannot be changed afterwards To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1276037/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
