Getting the mute key to work with Ubuntu 9.04 64 bit and a T400

Found a great site here that has some great information about ubuntu and the Thinkpad T400. A great little tip found there is how to get the mute button working on the T400 so that it shows up correctly in gnome. I tried this on my Ubuntu 9.04 64 bit install and it worked perfectly.

The process is to simply add acpi_osi="Linux" to the end of the grub boot string!

You can do this with:
$ sudo vi /boot/grub/menu.lst
Then find the line towards the bottom that launches the correct option. It will start with:
kernel /boot/
Just put the string
acpi_osi="Linux"
onto the end of this line.
Save and restart
Nice!