Comment 2 for bug 1358366

I've gone through the following steps to solve this issue for me.

- create [1] '/usr/bin/fixlightdmxrandr.sh'

- execute 'xrandr' and find out the display you want to disable (INTERNAL_OUTPUT)

- modify '/usr/bin/fixlightdmxrandr.sh' accordingly

- edit [2] '/etc/lightdm/lightdm.conf' to include the '/usr/bin/fixlightdmxrandr.sh' script.

- reboot, or restart lightgdm

- hopefully enjoy your new fullscreen lightdm ;-)

[1] '/etc/lightdm/lightdm.conf'

<code>
[SeatDefaults]
allow-guest=false
display-setup-script=/usr/bin/fixlightdmxrandr.sh
session-setup-script=/usr/bin/fixlightdmxrandr.sh
</code>

[2] '/usr/bin/fixlightdmxrandr.sh'
<code>
#!/bin/sh
EXTERNAL_OUTPUT="HDMI2"
INTERNAL_OUTPUT="LVDS1"

xrandr |grep $EXTERNAL_OUTPUT | grep " connected "
if [ $? -eq 0 ]; then
    xrandr --output $INTERNAL_OUTPUT --off --output $EXTERNAL_OUTPUT --auto
else
    xrandr --output $INTERNAL_OUTPUT --auto --output $EXTERNAL_OUTPUT --off
fi
</code>