This is happening since I upgraded from saucy to trusty. Installing the latest mainline kernel from http://kernel.ubuntu.com /~kernel-ppa/mainline/v3.14-rc1-trusty/ solves the issue.
-- 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 [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
