This probably isn't a kernel issue. Backlight drivers generally only change the brightness when told to do so by userspace, although sometimes system firmware plays a role as well.
But based on the described behavior, I suspect that it was userspace setting the brightness value when the login screen appeared. gnome- settings-daemon is what will actually be applying the brightness settings, so I'm going to reassign the Linux task to that. ** Package changed: linux (Ubuntu) => gnome-settings-daemon (Ubuntu) ** Changed in: gnome-settings-daemon (Ubuntu) Status: Triaged => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/974260 Title: Brightnes of laptop panel is set to minimum when system starts To manage notifications about this bug go to: https://bugs.launchpad.net/lightdm/+bug/974260/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs