HID Upper Filter

I have a KMDF based upper HID Class filter driver, works fine, but when I am trying to write a request from my own application (through a side-band communication interface), I get the following error

0xc00000e8 - An access to a user buffer failed at an “expected” point in time. This code is defined since the caller does not want to accept STATUS_ACCESS_VIOLATION in its filter.

Any ideas?

Thanks,
AB

Hi Guys

Any other info I need to provide for somebody to shed some light on this? Why would an upper filter on top of HIDClass wont be allowed to send down a request down the device?

Thanks,
AB

Where is this error message coming from? STATUS_ACCESS_VIOLATION likely
means there’s something wrong with the buffer specified with the request.
How are you building the WDFREQUEST?

Probably the easiest way to debug this is to compare a working case with a
non-working case. Take a write that normally succeeds and dump the
underlying IRP:

  1. !wdfrequest
    2. !irp 1

    Then do the same with your failing request. You should be able to spot some
    difference that will tell you why one fails and the other doesn’t.

    -scott
    OSR
    @OSRDrivers

    wrote in message news:xxxxx@ntdev…

    Hi Guys

    Any other info I need to provide for somebody to shed some light on this?
    Why would an upper filter on top of HIDClass wont be allowed to send down a
    request down the device?

    Thanks,
    AB

Thanks Scott… will give it a go!