I'm using 14.04.1, and I have the exact same problem. The solution posted also works for me.
$ uname -a Linux lune 3.13.0-39-generic #66-Ubuntu SMP Tue Oct 28 13:31:23 UTC 2014 i686 i686 i686 GNU/Linux $ cat os-release NAME="Ubuntu" VERSION="14.04.1 LTS, Trusty Tahr" ID=ubuntu ID_LIKE=debian PRETTY_NAME="Ubuntu 14.04.1 LTS" VERSION_ID="14.04" HOME_URL="http://www.ubuntu.com/"; SUPPORT_URL="http://help.ubuntu.com/"; BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"; -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1388636 Title: [Lenovo V570 Notebook] Brightness not changing via UI widget in GNOME shell or hotkeys To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1388636/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
