Vista - Find out active graphics device programmatically (registry key)

Hello all.



I am trying to control graphics hardware acceleration programmatically.

My question is: How can I find the GUID of the active display device?

What I already found out:
The registry key for controlling this hardware acceleration is
HKLM\SYSTEM\CurrentControlSet\Control\Video\[GUID of graphics
card]\0000\Acceleration.Level

I thought that another registry key can be used to find out about the
graphics adapter GUID:
HKLM\Hardware\Devicemap\Video\ and there \Device\Video0
However on another computer it is not Video0 but Video7 and Video8

Is there any (official) documentation on this matter?

Thank you in advance
Ulrich

Ok finally answered this one myself:

::EnumDisplayDevices(...) is your friend.
It delivers you DISPLAY_DEVICE.DeviceKey which is exactly the registry key I
am looking for.
I take it that the flag DISPLAY_DEVICE_PRIMARY_DEVICE in
DISPLAY_DEVICE.StateFlags signifies the device I am looking for.