[wdmaudiodev] Re: WDM Audio Subdevice registration and unregistration

  • From: AI Developer <developer@xxxxxxxxxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Fri, 29 Aug 2008 10:22:10 +0530

Tim Roberts wrote:
Joseph Thomas-Kerr wrote:
From: "Lee Laborczfalvi" <labor.lg@xxxxxxxxx>

I am working on modifying the MSVAD sample driver (simple) running on
Windows Vista in order to allow the Wave and Topology subdevices to be
registered in response to an IOCTL sent from a user mode process. 
This is
to provide dynamic subdevice creation functionality.  I am also adding
functionality to unregister the devices when a second IOCTL is received.
I'm doing something similar. I am writing a driver that was
originally  based on MSVAD multi. I want to add a new IOCTL to do some
auxilliary processing. However, I can't figure out how to inform the
port class of the handler routine for my new IOCTL. As far as I can
see, all IOCTLs go to its dispatch routine and I never see them in my

Can you fill me in on how to do this?
You don't.  MSVAD is a kernel streaming driver.  Additional
functionality is exposed through custom KS properties, not through ioctls.

That's the proper way to do it.

However, if you really wanted to handle IOCTLs, you would need to override the DeviceControl dispatch routine setup by the port class driver, handle your IOCTLs in a way you want, and pass the rest to the port class driver's handler.

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