It’s both nice and bad when I upgrade to a newer Ubuntu version. The good part is I have lots of posts material for the blog but the bad part is there’s always something on my main computer or netbook which doesn’t work out of the box and needs tweaking.

I really didn’t expect the Fn keys to work out of the box on my Asus EeePC 1005HA (so this method has only been tested for this Asus EeePC model, I don’t know if it works on others) and unfortunately I was right. However, the fix is very quick. Here’s what you have to do.

Notice: editing the Grub can be dangerous so be very careful not to change anything else!

To enable the Fn keys on an Asus EeePC 1005HA (possibly other models too) with Ubuntu 10.04 Lucid Lynx, open a terminal and type:

[bash]
sudo gedit /etc/default/grub
[/bash]

and search for the line that says:

[bash]
GRUB_CMDLINE_LINUX_DEFAULT
[/bash]

This line should originally look like this:

[bash]GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"[/bash]

Add acpi_osi=Linux to the end of the line, before the closing quote. Basically after you edit it, the line should look like this:

[bash]
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux"
[/bash]

Once you’re done, save the file and run the following command:

[bash]
sudo update-grub
[/bash]

Now reboot!

source : http://www.webupd8.org/2010/05/enable-fn-keys-on-your-asus-eeepc-and.html