This sounds like it might be a duplicate of https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/285323
Try killing gnome-power-manager and see if it solves the problem.
This sounds like it might be a duplicate of https:/ /bugs.launchpad .net/ubuntu/ +source/ gnome-power- manager/ +bug/285323
Try killing gnome-power-manager and see if it solves the problem.