I have toshiba satellite L745 with nvidia GEFORCE graphics card. I installed nvidia server setting from ubuntu software center. Still I can't decrease the brightness. When I use the function key to decrease, brightness indicator shows it's decreasing but it doesn't.
Looking up on this very site has brought me to this question and the solution mentioned there was:
- Open a terminal (Program - Accessories - Terminal)
- Type in "sudo gedit /etc/default/grub" (without the "")
- Find the line that says: GRUB_CMDLINE_LINUX="quiet splash"
- Edit it so it says: GRUB_CMDLINE_LINUX="quiet splash acpi_backlight=vendor"
- Save and exit
- Run the command "sudo update-grub" (again without quotes of course)
- Reboot and enjoy!
Hope this helps :)