Performing a Hardware Functionality Scan
A display miniport driver's Hardware Functionality Scan (HFS) ensures that the miniport driver communicates with the required hardware. For more information about HFS, download the Output Content Protection document at the Output Content Protection and Windows Vista website.
A display miniport driver must start performing an HFS whenever the Microsoft DirectX graphics kernel subsystem (Dxgkrnl.sys) calls the following driver functions:
DxgkDdiSetPowerState with the graphics adapter's power state set to D0.
The HFS can be asynchronous and is not required to complete before DxgkDdiStartDevice or DxgkDdiSetPowerState returns. However, no OPM DDI function can return until the HFS completes.