AVStreamDriver question.

NTDEV
1

Hi All,
I am writing a new AVStream driver so have some basic questions.

  1. If I do not specify the QUERY_INTERFACE entry point in KDEVICE structure then how does the AVStream gets the information about the interface?? Does it send that IRP directly to the bus driver? What about QUERY_CAPABILITIES?

  2. Can I forward the IRP like in WDM model to the lower driver if I have registered for the callback but do not want to handle the IRP??

Your help is really appriciated.

  • DC

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2

On Wed, Aug 08, 2007 at 11:51:22PM -0700, Driver Coder wrote:

Hi All,
I am writing a new AVStream driver so have some basic questions.

  1. If I do not specify the QUERY_INTERFACE entry point in KDEVICE
    structure then how does the AVStream gets the information about the
    interface?? Does it send that IRP directly to the bus driver? What about
    QUERY_CAPABILITIES?

Which interfaces are you talking about? The QueryInterface callback in
KSDEVICE is used for handling the plug-and-play QUERY_INTERFACE IRP, and
AVStream drivers do not normally use those. Instead, you'll just add
a new property set or method set, and use the KS interfaces from user
mode to access them.

  1. Can I forward the IRP like in WDM model to the lower driver if I have
    registered for the callback but do not want to handle the IRP??

If you don't want the IRP, you just return. The AVStream framework will
take care of calling the lower drivers, and it will make sure the order
is correct.

Tim Roberts, xxxxx@probo.com
Providenza & Boeklheide, Inc.