[wdmaudiodev] Re: Overriding IRP_MJ_DEVICE_CONTROL handling is possible?

  • From: Tom Eckert <teckert@xxxxxxxxxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Wed, 11 Apr 2007 10:40:07 -0400

Don,
This is from the topic "Introduction to Device Interfaces":

   "Typically, drivers register for only one interface class. However,
   drivers for devices that have specialized functionality beyond that
   defined for their standard interface class might also register for
   an additional class."
PortCls registers the standard interfaces and you'll be adding a registration for a custom interface. There is no conflict here as long as your handler passes all messages except the ones for your interface on to PortCls. 
Tom

Don Bell wrote:

On 4/10/07, Don Bell <0dbell@xxxxxxxxx> wrote:


In a "low level" WDM driver, I would of course use
IoRegisterDeviceInterface() to register the device interface. Thanks
to the book that I have, I also know that it should be done *after
creating* the device, but *before attaching* it to the device stack.


No wonder I am so confused... The book indeed instructs for calling
IoRegisterDeviceInterface() *before attaching* the device object to
the device stack.

However, the WDK documentation says:

"After creating the device object **and attaching it** to the device
stack, one driver calls IoRegisterDeviceInterface..."

Well, now at least I know that I can afford calling
IoRegisterDeviceInterface() after calling PcAddAdapterDevice().

However, I am still confused about the role of
IoRegisterDeviceInterface() in the world of PortCls. I tried to
document my qualms in microsoft.public.development.device.drivers:
http://tinyurl.com/yqeway

Many thanks,
Don
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