none
Help with UMDF upper class filter driver RRS feed

  • Question

  • Hi,

    My first step into writing a UMDF driver and I wondered if anyone can see what I'm doing wrong.  I'm trying to write an upper class filter for the WPD class so I created a UMDF driver project and made the following changes:

    1) Add fxDeviceInit->SetFilter to device.cpp
    2) Changed the inf file:

    a) Added UmdfKernelModeClientPolicy=AllowKernelModeClients & UmdfDispatcher=FileHandle to MyDevice_Install.NT.Wdf section
    b) Set class=wpd and classguid accordingly
    c) Removed ClassInstall32 and associated AddReg section

    Installed the driver via "devcon.exe install umdfdriver.inf root\umdfdriver"
    Edited "HKLM\System\CCS\Control\Class\{WPDGuid}\upperfilters" to include "umdfdriver"
    Install wpdhelloworld sample but the device doesn't start, code 19
    If I restore "upperfilters" to original value then the device can be enabled

    Hopefully something obvious but I haven't found anything in the UMDF docs

    Thanks for the help,

    Friday, February 28, 2014 4:05 PM