It sounds like a possible regression in kernel 5.4. Can you try an older or newer kernel?
https://kernel.ubuntu.com/~kernel-ppa/mainline/ -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1864698 Title: Can't change laptop-screen brightness on Dell XPS 13 9370 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1864698/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
