brightness not working ubuntu 16.04 LTS [duplicate]

Question

I've a Sumsung series 5 laptop with 4GB ram dual booted with Windows 10 and Ubuntu 16.04 LTS. My brightness does not work although the "function key+brightness button" shows the indication that it is being changed but brightness just does not really change. It works fine on Windows 10.

I tried sudo gedit /usr/share/X11/xorg.conf.d/20-intel.conf

    Section "Device"
            Identifier  "card0"
            Driver      "intel"
            Option      "Backlight"  "intel_backlight"
            BusID       "PCI:0:2:0"
    EndSection

Also,

sudo gedit /etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" to 
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_native_backlight=1"

Still the problem is there

please help

Answer 1

I had the same problem. I found a workaround by creating aliases to change the brightness value manually.

The file that contains the brightness value is:

/sys/class/backlight/intel_backlight/brightness

or something similar depending on your machine.

You can use an alias like that to add 100 to the brightness value:

bup='pres="$(cat /sys/class/backlight/intel_backlight/brightness)" && pres=$(($pres+100)) && echo $pres | sudo tee /sys/class/backlight/intel_backlight/brightness'

You can set up similar aliases to set it to lower the brightness or set it to specific values

Setting permanent alias

if you want your aliases to be available even after you reboot your machine, you should append the alias definition to the file:

~/.bashrc