Macbook Pro backlight control not working on Ubuntu 16.04

What I did was:

sudo vim /etc/rc.local 

and added the following line before the exit line

setpci -v -H1 -s 00:01.00 BRIDGE_CONTROL=0

then just reboot.

That worked for me.

1. In the Terminal application enter:

sudo nano /usr/share/X11/xorg.conf.d/10-nvidia-brightness.conf

2. Paste:

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "[GPU]"
    Option         "RegistryDwords" "EnableBrightnessControl=1"
EndSection

3. In a new terminal tab (Control + T) or window enter:

lspci | grep -i --color 'vga\|3d\|2d'

4. In the first terminal substitude the word [GPU] for the name between brackets shown in the second terminal, leaving out the brackets.

5. Save the document in the first terminal (Control + O), and reboot the computer.