I confirm it on a thinkpad x230 with stock kernels since 14.04. I reattach the external monitor then detach again which seems to consistently return the brightness controls to a working state.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1291371 Title: thinkpad screen dims after unplugging external display, and won't re- brighten without leaving X To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1291371/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs