Comment 3 for bug 23220

i think it involves more, acpi-support needs to be notified from xorg about
having a internal and external display, the screensaver (whichever) needs to be
hacked up to respect such a notification that gets handed through from
acpi-support and only save the internal screen, its a pretty major change and
additionally the security should get thought ove... if i lock my laptop, i dont
want someone to be able to just plug in a external monitor to get access
without password.