The buttons work (out of the box) and brightness is preserved (with acpi_backlight=vendor in GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub and sudo update-grub).
Brightness is controlled between 0 and 255 by ±1 (by echoing to /sys/class/backlight/amdgpu_bl0/brightness), but buttons change it only by ±12, which is very coarse to my eyes. Ideally, I'd like to have a logarithmic scale or, at least, to make it change by ±1.
I expect to find some configuration file to set the step or all the levels manually.
I'm aware of xbacklight and, perhaps, it could work, but I believe there's a native way without any additional software.
1 Answer
I must disappoint you because I cannot provide a native way without additional software. Just indicating how I implement brightness keys with a smaller incremental change.
I use the utility light, which in recent versions of Ubuntu can be installed with the command sudo apt install light. Otherwise, it can be installed from the github page of the author.
The command light -A 1 will increase brightness by 1%, light -U 1 will decrease brighness. I bound these commands to the keys Ctrl+Brightness Up/Down. The utility allows to define a minimum brightness, so you never blackout your screen.
