Keep forgetting to u/l this script for toggling the r500 backlight using toshset:
STATE=`sudo $TOSHSET -trmode 2>/dev/null | grep -a transreflective | \
cut -f 3 -d ' '`
if [ $STATE = "on" ]
sudo $TOSHSET -trmode $NEW_STATE
Xev shows the keycode for the backlight (and the 'i' internet/information/idiot key, so they'll both do the same thing) to be 180, which is already taken by XF86HomePage in Ubuntu. If for some reason this key is undefined (i.e. nothing shows up on `xmodmap -pke | grep '^keycode 180'`), add the following line to ~/.Xmodmap (which might need to be symlinked to ~/.xmodmaprc on non-Ubuntu Linuxes):
keycode 180 = XF86HomePage
In E17, edit the keyboard bindings using Settings-> Settings Panel -> Input -> Key Bindings. For XF86HomePage, select the Launch : Defined Command option, and point it to the above shell script (e.g. in ~/bin).
Note that the script uses sudo to launch toshset, so you will either need to change this to invoke an GUI sudo program like gtksu, or add a line like the following to /etc/sudoers:
$USER ALL=(root) NOPASSWD: /usr/local/bin/toshset
where $USER is your username. Note that this allows any toshset command to be run as root without a password from this user's session, which could be exploited if someone were sufficiently motivated.