Brightness issue in a Lenovo ThinkPad Edge LR236W5

After upgrade from 13.04 to 13.10 Brightness is not working. Please let me know how to fix this issue,

Machine configurations given below.

id: thinkpad
description: Notebook
product: 0301G8G ()
vendor: LENOVO
version: ThinkPad Edge
serial: LR236W5
architecture:   64 bits

Solution 1:

Have you tried this:

• Open terminal ( Ctrl+Alt+T ) and type:

  sudo cp /etc/default/grub /etc/default/grub.bak
  sudo gedit /etc/default/grub
  

  You will find this line in the new opened window: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

• Change it to:

  GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
  

• Save and close the window and type this in the terminal:

  sudo update-grub
  

• Restart your system..

if above procedure doesn't work then repeat the same step but this time try to change the above mentioned line with:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash pcie_aspm=force"

_{Note: The next line to the line mentioned above should be GRUB_CMDLINE_LINUX="" not GRUB_CMDLINE_LINUX="acpi_osi=Linux"}