####Issue :
My Dell OptiPlex 3030 Unbuntu machine cannot save brightness, it goes to maximum brightness every time I save to lower brightness and reboot. It looks like related to Ubuntu. I found out a solution for it.
####Workaround :
-
Modify grub file
In terminal, type command to open grub file
sudo gedit /etc/default/grub
then change GRUB_CMDLINE_LINUX to
GRUB_CMDLINE_LINUX="acpi_backlight=vendor"
save the changes, then type
sudo update-grub
to reflect the changes
-
Get brightness value
Adjust brightness for machine, type command in terminal and then check the value
sudo gedit /sys/class/backlight/intel_backlight/brightness
it is 1917 in my machine
-
Setup sudo with no-password
Type command to open sudoers file
sudo gedit /etc/sudoers
then change %sudo ALL=(ALL:ALL) ALL to
%sudo ALL=NOPASSWD: ALL
save the changes
-
Modify profile file
Type command to open profile file
sudo gedit /etc/profile
at the end of file, add below lines
sudo -S sh -c 'echo 1917 > /sys/class/backlight/intel_backlight/brightness'
save the changes and reboot the machine to verify the result