I've done some more testing, and I believe I've pinned the issue to i915 kernel module.
$ head /sys/class/backlight/intel_backlight/* ==> /sys/class/backlight/intel_backlight/actual_brightness <== 1023 ==> /sys/class/backlight/intel_backlight/bl_power <== 0 ==> /sys/class/backlight/intel_backlight/brightness <== 1023 ==> /sys/class/backlight/intel_backlight/device <== head: error reading '/sys/class/backlight/intel_backlight/device': Is a directory ==> /sys/class/backlight/intel_backlight/max_brightness <== 1023 ==> /sys/class/backlight/intel_backlight/power <== head: error reading '/sys/class/backlight/intel_backlight/power': Is a directory ==> /sys/class/backlight/intel_backlight/scale <== unknown ==> /sys/class/backlight/intel_backlight/subsystem <== head: error reading '/sys/class/backlight/intel_backlight/subsystem': Is a directory ==> /sys/class/backlight/intel_backlight/type <== raw ==> /sys/class/backlight/intel_backlight/uevent <== When trying to directly modify brightness, $ echo 100 | sudo tee /sys/class/backlight/intel_backlight/brightness 100 the value is recorded, $ cat /sys/class/backlight/intel_backlight/brightness 100 but brightness stays the same. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2161394 Title: Brightness hotkeys have no effect in Dell Laptop To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2161394/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
