Switching on and off the external screen on an HP 6910p with Radeon X2300

{syntaxhighlighter brush:bash}
:~$ cat bin/screen-dock.sh
xrandr --output DVI-D_1 --mode 1920x1200
xrandr --output PANEL --off
:~$ cat bin/screen-undock.sh
xrandr --output PANEL --mode 1280x800
xrandr --output DVI-D_1 --off
{/syntaxhighlighter}