[wdmaudiodev] Re: Overriding IRP_MJ_DEVICE_CONTROL handling is possible?

  • From: Tom Eckert <teckert@xxxxxxxxxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Mon, 09 Apr 2007 14:16:36 -0400

Don,
Glad to offer what help I can, as you have already discovered the resource material gets sketchy as you try to expand past the miniport functionality.

On one hand, the book that
I have ("Writing Windows WDM Device Drivers" by Chris Cant) does an
excellent job in explaining the "assembly language" of WDM
programming. On the other hand, this could be very misleading when
writing a miniport driver... as I will soon explain in a very
fundamental question that I will present further down:
This material will be helpful in handling the custom IOCTLs correctly but it won't help you with the miniport aspects.
How am I supposed to know that I should use PcDispatchIrp()
instead of the "manual approach"? Now that I know about it, I can find
it in WDK's reference section but... Isn't there a tutorial that
provides a recipe for such scenario (which I am sure is not rare)?
I agree it should be easier to find a miniport+custom IOCTL example but I don't know of any. Our driver uses the FileObject->FileName in the STACK_LOCATION which is always zero when the device (as opposed to a file) is opened to distinguish our custom IOCTLs.
I understand that this symbolic link should
be different than the one created by PortCls? Am I correct?
Correct. BTW, the documentation will tell you to use *IoRegisterDeviceInterface* instead of *IoCreateSymbolicLink. *which is probably a good idea, though I've never tried that route. * *We use the latter for backward compatibility.
Lastly, do you know of any book that specializes in Audio device
drivers? Chris Cant's book is good but its main focus is on  HID and
USB device drivers. I wish I had book that could "lead me by the hand"
as I am learning this exciting new field.
Intel has a new book on HD Audio but I couldn't find it on Amazon or Intel's site. I got a copy through last year's WinHEC. It has some good information on audio system software but it's not specifically a device driver book. Walter Oney's book is an excellent reference for WDM, but again, no specific info on audio miniports.

Tom

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