Legal values are 0 to whatever is in max_brightness OK, the next step is to double check there exists no other
/sys/class/backlight/* directory. Just in case you have multiple backlight devices, which is not uncommon. Regardless, I think we are at the stage where it can be said to be a kernel bug. Are you able to identify an older kernel version which doesn't have the bug? Or even if you boot 19.10 from USB? ** Package changed: ubuntu => linux (Ubuntu) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1862835 Title: [Dell XPS 15 9570] Unable to change laptop screen brightness or keyboard backlighting To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1862835/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
