IRP_MN_QUERY_INTERFACE called twice when loading driver why?

OSR_Community_User · January 19, 2002, 12:02am

hi all,

when I load the driver for the pci card, the PNP MANAGER CALLS the dispatch
function with following MINOR FUNCTIONS in the same order given below:

UNKNOWN MINOR FUNCTION 0x18
IRP_MN_FILTER_RESOURCE_REQUIREMENTS
IRP_MN_QUERY_INTERFACE
IRP_MN_QUERY_INTERFACE
IRP_MN_START_DEVICE
IRP_MN_QUERY_CAPABILITIES
IRP_MN_QUERY_PNP_DEVICE_STATE
IRP_MN_QUERY_DEVICE_RELATION

I would like to know, in the above sequence, why

IRP_MN_QUERY_INTERFACE alone is called twice one after the other…

thanx,

shiv

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Mark_Roddy · January 19, 2002, 6:52am

a) the InterfaceType could be different for each instance.
b) there is no limit to the number of times you could receive this IRP,
nor is there any rule other than ‘after add device’ about when this IRP
may arrive, nor does it affect your pnp state.

=====================
Mark Roddy
Windows XP/2000/NT Consulting
Hollis Technology Solutions 603-321-1032
www.hollistech.com
xxxxx@hollistech.com
For Windows Device Driver Training: see www.azius.com

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Shiva Prasad. T.
S.
Sent: Saturday, January 19, 2002 12:00 AM
To: NT Developers Interest List
Subject: [ntdev] IRP_MN_QUERY_INTERFACE called twice when loading driver
why?