IRP_MN_QUERY_RESOURCES is equivalent to "What resources is the device
decoding right now?
IRP_MN_QUERY_RESOURCE_REQUIREMENTS is equivalent to “What is the set
of possible sets of resources that this device could use?”
The first is useful for making sure that the PnP manager doesn’t
accidentally create resource conflicts between an early-starting
driver and a later-starting driver. Since it knows what resources the
later-starting device is using, it can choose other values for the
early-starting devices.
The second is useful for choosing possible configurations when
starting a device.
- Jake Oshins
“salman razzaq” wrote in message
news:xxxxx@ntdev…
Hi all,
I was just reading the DDK docs when I stuck in PNP minor IRPs. I
have a question, when a bus function driver reports the arrival of a
new device to PnP manager. It sends a number of PNP minor IRPs to the
PDO of the new device out of which one is IRP_MN_QUERY_RESOURCES.
According to the docs, these resources are for booting the devcie.
But, I do not understand where and when these resources are assigned
to either PDO or FDO of the device and by which IRP.
IRP_MN_QUERY_RESOURCE_REQUIREMENTS is used for querying device
resources and the device got those resources assigned through
IRP_MN_START_DEVICE.
Thank you.