[[Solved]] Acer V3-571G Brightness Problem in Ubuntu 14.04

If you are facing problem with your screen's brightness with your Acer V3-571G laptop; you can try the working solution below:

This is the solution amongst the various solutions available in the internet that worked for me.

1. First open Terminal with CTRL + ALT + T

2. Run the following command in the terminal:

 sudo gedit /etc/default/grub  

then change

 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"  
 GRUB_CMDLINE_LINUX=""  

to

 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"  
 GRUB_CMDLINE_LINUX="acpi_osi=Linux"  

then SAVE & RUN

 sudo update-grub   

Finally RESTART your laptop for the changes to take effect.