I have had issues with screen brightness not saving in my Clevo Sky-X4C-P7xxTM1-G since 18.04 LTS. I have tried this solution and it didn't work for me. I did make some progress with editing grub when I put
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=video" at least the slide bar would save it's position after a reboot. Moving the bar will change the brightness too.
However, when I reboot the screen remains at full brightness even though the bar is showing the lower setting.
Next I tried to make the
/usr/share/X11/xorg.conf.d/80-backlight.conf file with the following settings:
Section "Device" Identifier "Intel Graphics" Driver "intel" Option "AccelMethod" "sna" Option "Backlight" "acpi_video0" BusID "PCI:0:2:0" EndSection
sudo update-grub each time. After reboot I'm in a black screen with a prompt. I hit alt+F1 and am able to get shell prompt. I commented out everything in the conf file than reboot and now I'm stuck. As I mentioned before I have a Clevo which comes with Intel onboard graphics disabled. All of the video is handled by the Nvidia graphics card. I suspect that the reason this didn't work in my case is because the
80-backlight.conf doesn't have the correct parameters. Does anyone have any clue how I can put the right information into the file? Does the xbacklight package even handle this?