Re: IRP_MN_QUERY_INTERFACE : What is it different in XP ?

Hi walter oney

Thanks for the reply . I have done that already . If I do that I receive a
error message saying that the driver start error (10). In the debugger , I
understand why it is sending the IRP_MN_REMOVE_DEVICE right away . One more
thing , I did not have this problem in Windows 2000. Same driver works fine
in W2K , I did not even see IRP_MN_QUERY_INTERFACE anytime . I have no idea
why it is coming specially in Windows XP . Another thing what I tried is to
pass down the request IRP_MN_QUERY_INTERFACE to next level . This works for
the first child and after second child loading system either bug check or
freeze . Bug check is also different each time when I try to load .

I am having two child devices , over that USB audio driver is loaded . Can
you point me what exactly I need to in this case like how to complete the
request properly as a bus driver . or Any pointers to solve this problem ?

Thanks in advance

-----Original Message-----
From: Walter Oney []
Sent: Saturday, November 02, 2002 2:02 AM
To: NT Developers Interest List
Subject: [ntdev] Re: IRP_MN_QUERY_INTERFACE : What is it different in XP

“Deevi, Srinivasa” wrote:

I am having some problem with IRP_MN_QUERY_INTERFACE in windows XP . As
Walter oney’s book, in the multifunction sample , for a child device this
query is ignored . As per XP ddk , we need to handle this IOCTL if the
driver is bus driver . And windows 2000 does work fine even when we ignore
the IRP_MN_QUERY_INTERFACE request ( that means completing the request in
the Child Pnp handler ) . Anybody know why is this difference ?
Can anybody fill me with what exactly I need in this case ? What do I
when I get a IRP_MN_QUERY_INTERFACE in child PnP handler ?

I didn’t need to change MULFUNC for XP. Certainly, you can just complete
the IRP with the status code that’s already in the IRP if you don’t
recognize the interface guid.

Walter Oney, Consulting and Training
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