How to Enable Brightness Buttons when acpi_osi of Grub not enough in Debian of Zenbook?

- Initial condition: brightness-control buttons do not work, no animation of brightness-control not seen on actions, but manual control of brightness work in Settings and at the top-bar. - Condition after test code 1: brightness-control buttons do not affect brightness but visual animation is shown after reboot; however, now, the manual control of brightness do not work anymore so the solution which works in Ubuntu does not work in Debian. - I have tried here both GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=" and GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_osi=" in /etc/default/grub unsuccessfully, where the option without splash is the default setting in Debian, in contrast to Ubuntu. The complete default option is only with quiet in Debian. Differential solutions --- 1. Use defaults. Undo changes of Test code 1. Weakness: brightness keys do not work but you can control brightness from the top-bar. 2. ? Test code 1 --- I can fix the brightness-control buttons (fn+f5, fn+f6 for brightness decrease and increase, respectively) in Ubuntu 16.04 as described in the thread How to Enable Brightness Buttons when acpi_osi of Grub not enough in 16.04 of Zenbook? but not in Debian 8.5. There is no directory /usr/share/xorg.conf.d/ in Debian, in contrast to Ubuntu, so possibly similar work flow does not work in Debian. Main points done in the following work flow in Debian 1. Add code in /etc/default/grub # guillaume-desclaux https://ubuntuforums.org/showthread.php?t=2243162 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=" # I also tried here without splash, since it did # not exist by default in Debian, in contrast to Ubuntu. 2. Create directory /usr/share/xorg.conf.d/ 3. Add the following content in the file /usr/share/xorg.conf.d/20-intel.conf # https://askubuntu.com/a/536618/25388 Section "Device" Identifier "card0" Driver "intel" Option "Backlight" "intel_backlight" BusID "PCI:0:2:0" EndSection 4. Run as root update-grub My work flow in Debian root@masi:/home/masi# vim /etc/default/grub root@masi:/home/masi# vim /usr/share/x xfig/ xml/ xml-core/ xsessions/ root@masi:/home/masi# mkdir /usr/share/xorg.conf.d/ root@masi:/home/masi# vim /usr/share/xorg.conf.d/20-intel.conf root@masi:/home/masi# sudo update-grub bash: sudo: command not found root@masi:/home/masi# update-grub Generating grub configuration file ... Found background image: /usr/share/images/desktop-base/desktop-grub.png Found linux image: /boot/vmlinuz-4.6.0-0.bpo.1-amd64 Found initrd image: /boot/initrd.img-4.6.0-0.bpo.1-amd64 Found linux image: /boot/vmlinuz-3.16.0-4-amd64 Found initrd image: /boot/initrd.img-3.16.0-4-amd64 Adding boot menu entry for EFI firmware configuration done root@masi:/home/masi# Output: brightness keys not working after reboot; you now see the visual effect but no effect; after the changes, the brightness control also break if you try to manually change it. Hardware: Asus Zenbook UX303UA OS: Debian 8.5 64 bit Linux kernel 4.6