I am using umdf rc1 on vista x86 rc1. After I send a vender defined control
command to the device expecting a ULONG returned, the IWDFIoRequest->Send()
with synchonous method return S_OK,
IWDFRequestCompletionParams->GetCompletionStatus() also return S_OK. So it
seems the the control command have been sent to the device, and the device
completed the operation. But the
IWDFRequestCompletionParams->GetInformation() return 0, which is expected to
return sizeof(ULONG) for this control command and the output buffer is not
updated. I have an old WMD driver for the same device, and with the same
control command, it returnd a ULONG. What would be the problem? Can it be
that the device never reveives the command? or the device dose receive the
command, but fails to execute the command, and therefore not returning a
ULONG?

I have working on this for quite a few days and not able to figure it out. I
desperately need help.