Upper Filter Drivers.

NTDEV
1

Hi All,
I am new to device drivers field. I am trying to build Upper filter driver for USB device. After installing I verified stack using device tree. I found my upper filter has created seperate stack just like PartMgr used to create. I am able to get all PNP related IRPs. But I am Unable to get other IRPs like IRP_MJ_INTERNAL_DEVICE_CONTROL or IRP_MJ_DEVICE_CONTROL in my upper filter driver.

When I have made it lower filter driver then I am able to get all IRPs.

As according to my understanding IRPs from IoManager should come to upper filter driver first and then to the functional driver and then to lower filter driver. Is there any special method to get all IRPs going to functional driver in upper filter driver.

Thanks in Advance…

Eris

2

An upper filter may not see internal IOCTLs, especially if the upper edge of the device you are filtering communicates with user mode which cannot send internal IOCTLs. Also, an upper filter should be in the same stack as the device it is filtering, not a separate stack. If you are filtering the right stack, you should see all incoming io to the device. As an upper filter, you will *NOT* see io that the driver below sends down the stack though

d

-----Original Message-----
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Sent: Tuesday, September 02, 2008 4:05 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] Upper Filter Drivers.

Hi All,
I am new to device drivers field. I am trying to build Upper filter driver for USB device. After installing I verified stack using device tree. I found my upper filter has created seperate stack just like PartMgr used to create. I am able to get all PNP related IRPs. But I am Unable to get other IRPs like IRP_MJ_INTERNAL_DEVICE_CONTROL or IRP_MJ_DEVICE_CONTROL in my upper filter driver.

When I have made it lower filter driver then I am able to get all IRPs.

As according to my understanding IRPs from IoManager should come to upper filter driver first and then to the functional driver and then to lower filter driver. Is there any special method to get all IRPs going to functional driver in upper filter driver.

Thanks in Advance…

Eris

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