In particular, implement IMiniportAudioSignalProcessing::GetModes, and respond to QueryInterface for IID_IMiniportAudioSignalProcessing, and portcls will call into your GetModes() method. This should work even though you are WaveCyclic and not WaveRT. The relevant code in http://code.msdn.microsoft.com/windowshardware/slate-system-virtual-audio-f241062f/sourcecode?fileId=86816&pathId=1882676779 is: // minwavert.h class CMiniportWaveRT : public IMiniportWaveRT, public IMiniportAudioEngineNode, public IMiniportAudioSignalProcessing, public CUnknown ... IMP_IMiniportAudioSignalProcessing; // minwavert.cpp STDMETHODIMP_(NTSTATUS) CMiniportWaveRT::NonDelegatingQueryInterface ... else if (IsEqualGUIDAligned(Interface, IID_IMiniportAudioSignalProcessing)) { *Object = PVOID(PMINIPORTAudioSignalProcessing(this)); } ... NTSTATUS CMiniportWaveRT::GetModes ( _In_ ULONG Pin, _Out_writes_opt_(*NumSignalProcessingModes) GUID* SignalProcessingModes, _Inout_ ULONG* NumSignalProcessingModes ) From: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Matthew van Eerde Sent: Tuesday, January 21, 2014 8:01 AM To: wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] Re: How to support IMiniportAudioSignalProcessing in WaveCyclic based audio driver? Yes, the WaveCyclic miniport model supports IMiniportAudioSignalProcessing. What do you do with the audio data once you get it? That is, what is the layer below you? That should determine your choice of WaveCyclic or WaveRT. From: wdmaudiodev-bounce@xxxxxxxxxxxxx<mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx> [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Danny Sent: Tuesday, January 21, 2014 1:28 AM To: wdmaudiodev@xxxxxxxxxxxxx<mailto:wdmaudiodev@xxxxxxxxxxxxx> Subject: [wdmaudiodev] How to support IMiniportAudioSignalProcessing in WaveCyclic based audio driver? Hello, my driver is a virtual sound driver based on WaveCyclic. It worked fine on Windows 8, but during WHCK KsPosition test, the test fails with the following error message. Message 12/6/2013 2:10:26.125 PM Failed to query for basic support KSPROPERTY_AUDIOSIGNALPROCESSING_MODES: Last error:1170 Can I add support for IMiniportAudioSignalProcessing in WaveCyclic based audio driver? I've noticed that the new WDK sample SysVad support IMiniportAudioSignalProcessing property. But it was based on WaveRT. Or should I change my project to WaveRT based example? Does WaveRT works for virtual sound driver? (We don't have the codec hardware, just to capture the pcm audio data and send out to another stack.) Thank you! -- Danny