Toshiba Nvidia LCD Brightness Fix

After installing Linux Mint 13 on the laptop, a Toshiba P500 I found the X server wouldnt reduce or increase brightness with the keyboard keys. After trying many a fix found around and nothing worked however I finally have a fix. If you have the same problem try the following

Open a console and run the following commands

Scroll down and find the line that will be similiar or exactly like:
GRUB_CMDLINE_LINUX_DEFAULT= "quiet splash"

now modify the line and add the parameter acpi_osi=, so the line should now read

Save and exit the text editor, and run the following command to update grub

To test the settings reboot

Upon relogging back in test your hardware keys, and your brightness should chage like they always did