Do WDDM drivers still use video request packets as XDDM did? RRS feed


  • The answer is no.

    There still is a DDI function DxgkDdiDispatchIoRequest. WDDM documentation doesn't tell for which specific legacy case this DDI function is left over. It can't be much however. We have never seen it involved in any relevant WDDM functionality. The Sun Virtual Box WDDM sample driver source code even seems to have an assertion in the implementation of this DDI function. So it might not even get called at all...

    Even if your application finds the right Device Object (it probably doesn't), then if your application can open the device object (it probably can't), then if DirectX Kernel lets IOCTLs from unknown source pass to the miniport driver (it probably doesn't), then if the WDDM miniport driver can handle the packet (it probably can't), I would still not dare to implement this. There is no documentation about support for such an approach. Even if it seems to work today (it probably doesn't), it might cease to do so tomorrow.

    Thursday, May 19, 2016 4:30 PM