Determining the Orientation of the screen rather than the orientation of the device

The [[UIDevice currentDevice] orientation] method returns a number of orientations beyond the portrait and landscape orientation. I am well aware of checking to see if the orientation returned is "valid", unfortunately if the orientation returned is NOT "valid" when my app requires a specific orientation to determine which methods to run, I have no way of knowing which method is appropriate.

I have attempted a number of solutions to this, but for now the only thing I have been able to work out is to check to see if the orientation is LandscapeLeft or LandscapeRight and if it isn't I assume the screen is in portrait orientation. Unfortunately this isn't true when the device is face up and the screen is in landscape orientation.

I attempted to use the parent view controller's orientation:

parentController.interfaceOrientation;

Unfortunately it returned UIDeviceOrientationUnknown. I search SO and Google for someone else who has faced this problem. It seems silly to me that Apple would have anything but LandscapeLeft/Right and PortraitUp/Down for their orientations.

What I really need is the APPS orientation not the devices, since these are sometimes at odds. Any advice?