The Windows 98 DDK contains sample source code for a generic WDM driver in the \ddk\src\general\sys directory. Building this sample yields a binary file named Testdrv.sys. This article discusses how to create an inf and modify the sample so that it can be used as a generic WDM PnP driver.
The sample as it exists in early versions of the Windows 98 DDK (including the July and October 1998 MSDN releases) does not function correctly as a PnP driver. Using the driver results in Device Manager displaying error code 7 (CM_PROB_FAILED_FILTER).
The problem is that the DRVSHELL_Dispatch function in Drvshell.c by default sets Irp->IoStatus.Status = STATUS_SUCCESS. The IRP_MJ_PNP handler does not explicitly handle the IRP_MN_FILTER_RESOURCE_REQUIREMENTS IRP. When Ntkern.vxd sees that this IRP has been completed and IoStatus.Status = STATUS_SUCCESS, it expects that the driver has set IoStatus.Information to point to an IO_RESOURCE_REQUIREMENTS_LIST structure containing the filtered resource list. Because the sample driver fails to set IoStatus.Information appropriately, Ntkern.vxd emits a "Filtering into nothing, returning failure" debug message and fails the CONFIG_FILTER message resulting in the error code 7.
The following code shows how an IRP_MN_FILTER_RESOURCE_REQUIREMENTS handler can be added to the sample driver to work around this problem by indicating that it is not filtering the resource requirements:
case IRP_MJ_PNP:
DEBUG_LOG_PATH("IRP_MJ_PNP_POWER");
switch(irpStack->MinorFunction)
{
case IRP_MN_FILTER_RESOURCE_REQUIREMENTS:
DEBUG_LOG_PATH("IRP_MN_FILTER_RESOURCE_REQUIREMENTS");
Irp->IoStatus.Status = STATUS_NOT_IMPLEMENTED;
break;
Alternately, if resource filtering is required, the IRP_MN_FILTER_RESOURCE_REQUIREMENTS handler could leave IoStatus.Status = STATUS_SUCCESS and set IoStatus.Information to point to an IO_RESOURCE_REQUIREMENTS_LIST structure containing the filtered resource list.
The following sample inf installs Testdrv.sys as a WDM PnP driver loaded by Ntkern.vxd. This inf can be easily adapted for use with any hardware device by including the appropriate hardware ID in the [WDMTest] Device section:
[Version]
Signature="$CHICAGO$"
;set Class to appropriate type for your device
Class=Unknown
;set ClassGUID to appropriate value for the Class
;ClassGUID={XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}
provider=%Provider%
[SourceDisksNames]
1="WDM Test Driver Disk",,0
[SourceDisksFiles]
testdrv.sys=1
[Manufacturer]
%Manufacturer%=WDMTest
[WDMTest]
"WDM Test Driver"=WDM_Install, <your hardware ID>;
[WDM_Install]
CopyFiles=WDM.CopyFiles
AddReg=WDM.AddReg
[WDM.AddReg]
HKR,,DevLoader,,*NTKERN
HKR,,NTMPDriver,,testdrv.sys
[DestinationDirs]
WDM.CopyFiles = 10,system32\drivers ; %SystemRoot%\system32\drivers
[WDM.CopyFiles]
testdrv.sys
[Strings]
Provider="Your Provider Name"
Manufacturer="Your Manufacturer Name"
See the Windows 98 DDK for more information on WDM and PnP.