Loading a User-Mode Display Driver
You must set the following entry in an add-registry section of the INF file so that the user-mode display driver's DLL name is added to the registry during driver installation and so that the Microsoft Direct3D runtime can subsequently load the DLL:
[Xxx_SoftwareDeviceSettings] ... HKR,, UserModeDriverName, %REG_MULTI_SZ%, Xxx.dll
The INF file must contain information to direct the operating system to copy the user-mode display driver into the system's %systemroot%\system32 directory. For more information, see INF CopyFiles Directive and INF DestinationDirs Section.
The Direct3D runtime obtains the user-mode display driver's DLL name from the registry in order to load the user-mode display driver in the runtime's process space.