Windows

Currently reads as :

[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class{4d36e968-e325-11ce-bfc1-08002be10318}\0000] "FeatureTestControl"= "Edit DWORD 32 bit"= f000

Registry with New Value:

You needed to change the value in registry to:(f008)

[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class{4d36e968-e325-11ce-bfc1-08002be10318}\0000] "FeatureTestControl"="Edit DWORD 32 bit"=f008

Linux

1. You need to kill your display manager, to create new Xorg.conf file (because it runs X server):

• Press Ctrl+Alt+F1 (Dont panic, while your Window system is runing, you can go back with Ctrl+Alt+F7)
• typesudo service lightdm stop and press Enter(e.g. gdm, kdm, xdm)

2. Create new Xorg configuration file

• type X -configure and press Enter
• type mv xorg.conf.new /etc/X11/xorg.conf and press Enter

3. Start X Server (you can do it all without GUI via command line, but I was more comfortable with this aproach):

• typesudo service lightdm start and press Enter(e.g. gdm, kdm, xdm)

4. Modify Xorg.conf file

• navigate to /etc/X11/xorg.conf and open Xorg.conf (in my case latest was xorg.conf.05312015) via leafpad (e.g. gedit, pluma)
• search for Section "Device" and then for Driver (on my PC it said Driver "intel" by default, but it could be something else, so change it to intel)
• add line Option "Backlight" "intel_backlight" after Driver "intel" (it doesn't really matter where, as long as it stays in Device Section)
• save

5. Modify GRUB

• sudo gedit /etc/default/grub (e.g. leafpad, pluma...)
• set to GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=video" (acpi_osi= did it for me, other options didn't work...)
• in terminal type sudo update-grub and press Enter

6. Restart and profit

Funny thing is, that code is exactly the same as in /usr/share/X11/xorg.conf.d/20-intel.conf, but that way it worked as expected!