[wdmaudiodev] Re: WaveRT MiniportDriver receiving IRP_MJ_CREATE in D3

  • From: Surabhi Ghaisas <ghaisas.surabhi@xxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Wed, 23 Jul 2014 09:33:06 +0530

Thanks Tim. Yes, my device needs to be in D0 for IRP processing.

On Tue, Jul 22, 2014 at 10:36 PM, Tim Roberts <timr@xxxxxxxxx> wrote:

> Surabhi Ghaisas wrote:
> >
> > In WaveRT miniport driver I am exposing one device interface for use
> > by custom application by means of IoRegisterDeviceInterface. I want to
> > handle the IRPs that come for this interface in miniport driver
> > itself. For the same I have registered my own handlers for
> >
> > What I am observing is when there is no activity for my device my
> > driver enters D3 state as expected. After which when I launch my
> > custom application I receive calls to IRP_MJ_CREATE and then
> > IRP_MJ_DEVICE_CONTROL for registered interface as expected but all
> > this time  driver state remains D3. I do not get a call to change
> > driver state to D0 before receiving these IRP calls. Is this expected
> > behaviour?
> Yes.  It is up to the driver to decide when the device has to power up.
> For KS requests, the port driver has that knowledge.  When you bypass
> the port driver, you have to do it.
> By the way, you have opened a real can of worms here.  There are a large
> number of players involved (KS, Port class, Miniport, Bus), and each one
> of them thinks they own a piece of the power management pie.
> I'm a little surprised your device goes into D3.  I didn't know the
> WaveRT port driver would do that.
> > Should miniport driver make call to PoSetPowerState for IRPs that are
> > not passed on portclass?
> Do your IRPs require the device to be in D0?  If so, then you need to
> send an IRP_MJ_POWER with IRP_MN_SET_POWER.  One of the existing drivers
> will call PoSetPowerState.  I don't have any clue whether this will
> actually work.  The port driver thinks it is managing the power policy.
> --
> Tim Roberts, timr@xxxxxxxxx
> Providenza & Boekelheide, Inc.
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