Xorg has not managed the power settings for quite some time. Since the kernel interface apparently works, it doesn't sound like a drm driver bug. The kernel doesn't persist its settings, that's gnome's job. Bumping bug to the g-p-m queue.
** Package changed: xserver-xorg-video-intel (Ubuntu) => gnome-power-manager (Ubuntu) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/954661 Title: backlight brightness not adjustable by default on Dell XPS 13 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/954661/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs