Unable to change screen brightness on Toshiba Laptop with Ubuntu 13.04

Last week,  my friend gave me an old Toshiba laptop for my experiments and without any doubt I decided to install latest Ubuntu release (13.04). Though memory was less, without giving much trouble Ubuntu got loaded.  During the initial boot itself I noticed high level of screen brightness and hardware control keys were not responding. finally with the help of Ubuntu experts, I found a resolution.

First option was to Edit the grub configuration file:

      Open a terminal ( ctrl+alt+t )

 #sudo gedit /etc/default/grub

Then add the parameter by changing the line that reads:

GRUB_CMDLINE_LINUX=""

GRUB_CMDLINE_LINUX="acpi_backlight=vendor"

Save and exit gEdit

       Update Grub by issuing following command

#sudo update-grub

Then reboot the machine and check the hardware keys. 

The Second option was to install "Brightness indicator"

Using this indicator utility we can set  screen brightness in Ubuntu Unity

to install this utility in Ubuntu 13.04, we have to run following commands in terminal. 

    

#sudo add-apt-repository ppa:indicator-brightness/ppa

#sudo apt-get update && sudo apt-get install indicator-brightness

Once the utility is installed you can see a brightness indicator as below on your taskbar.

 Clicking the icon shows you all the possible brightness values, I could see a maximum of 7 steps. The current value will be indicated with a dot.