Comment 122 for bug 1303736

This light-locker remove "fix" does not work on my Thinkpad T61:
after lid open the screen is still black. I have to reset the X11 display with "xrandr --auto"

My (nasty) workaround is:

Create /etc/acpi/events/lidopen :

event=button/lid LID open
action=/etc/acpi/lidopen.sh

Create /etc/acpi/lidopen.sh :

su -l -c 'DISPLAY=:0 /usr/local/bin/xreset' $(ps aux | awk '/[\/]xinit/{print $1}')

Create /usr/local/bin/xreset :

xrandr --auto
killall xfce4-display-settings

In Ubuntu 12.04 there was /etc/acpi/lid.sh, see:

https://help.ubuntu.com/community/LaptopLidAndDockScripts

but this script has gone, some *CENSORED* have removed it.
Therefore one has to create /etc/acpi/events/lidopen and
/etc/acpi/lidopen.sh