Comment 5 for bug 164471

I don't think this bug should be closed until the "CRT/LCD" hotkey does its jobs.

If the external display is to be handled by xrandr then the bug is maybe a lack of assignation of the
ibm/hotkey HKEY 00000080 00001007 to a script in /etc/acpi.

(see bug #159185)

The fix could be something like creating /etc/acpi/events/thinkpad-crtlcd :

 # Turn on/off the external display
event=ibm/hotkey HKEY 00000080 00001007
action=/etc/acpi/external-display.sh

and creating /etc/acpi/external-display.sh

This last script should :
 - detect the screen resolution of the display of the laptop (LCD)
 - detect the capabilities of the external display (CRT)
 - use xrandr to cycle between : LCD alone, CRT+LCD, CRT alone
   with the CRT resolution beeing :
    - the LCD resolution if the CRT supports it
    - the highest CRT resolution available if the LCD resolution is not supported by the CRT

xrandr tips located at :
 http://www.thinkwiki.org/wiki/Installing_Ubuntu_6.06.1_on_a_ThinkPad_R60e#Using_xrandr_with_Ubuntu_7.10
should do the job.

Alternatively the hotkey could be masked away in /proc/acpi/ibm/hotkey and the display toggling could maybe be handled by the ibm firmware.