A driver has enumerated two child PDO's that returned identical Device ID's

Question

I have a kmdf bus driver PCI\VEN_XXXX&DEV_XXXX that creates two statically enumerated PDOs with serial numbers: 217 and 218; one for each Ethernet port. The PDO hardware id is ROOT\MY_NIC_PORT so I can install a NDIS Miniport driver on them.

The bus driver passes SDV and Verifier; but, on reboot two more PDOs get enumerated. On the next reboot I get a duplicate pdo crash.

The toaster example used the device class guid as part of the hardware id. When I tried that my NIC ports no longer showed up in device manager.

Any debug suggestion or work around idea would be appreciated?

pnpCaps.LockSupported = WdfFalse;
pnpCaps.EjectSupported = WdfTrue;
pnpCaps.Removable = WdfTrue;
pnpCaps.DockDevice = WdfFalse;
pnpCaps.UniqueID = WdfTrue;
pnpCaps.SilentInstall = WdfTrue;
pnpCaps.SurpriseRemovalOK = WdfTrue;
pnpCaps.HardwareDisabled = WdfFalse;
pnpCaps.NoDisplayInUI = WdfFalse;
pnpCaps.Address = SerialNo;
pnpCaps.UINumber = SerialNo;

************************************************************
Driver Verifier detected violation:

A driver has enumerated two child PDO's that returned identical Device
ID's.

CulpritAddress = FFFFF8025ED309C4, DeviceObject1 = FFFFE3882FB2F300, 
DeviceObject2 = FFFFE3882EBF88D0.
************************************************************

Jeffrey Tippet Jeffrey Tippet · Accepted Answer · 2017-08-23T20:09:59

There are a few versions of the toaster bus sample -- assuming you started with this one, then note that it saves its list of child PDOs in the registry. My guess is that your driver is both loading PDOs from the registry, and trying to dynamically create some too.

Set a breakpoint on your driver's version of Bus_PlugInDevice, and see how often it's getting called. Make sure it's never getting called 2x with the same Instance ID.

To clear up a bit of the naming thing: a device setup class is a GUID that is totally unrelated to its hardware ID. For NICs that want to interoperate with the OS's networking stack, you must use the NET setup class, {4d36e972-e325-11ce-bfc1-08002be10318}. You can put anything you want into your hardware ID. I don't really encourage you to put "ROOT\" in there, since that could be confused with a root-enumerated device (which your devices are not). Instead, you can use "yourcompany_yourdevice\port1" as a hardware ID.

While you're thinking about naming things, there are a few things to note about hardware IDs:

Once you assign a HWID, it's rather difficult to change it in a future driver update, without breaking customers who had already installed your device. So get it right the first time.
Once you assign an Instance ID, don't change or reuse it for the lifetime of the device. Otherwise you'll cause this bugcheck, or cause IP addresses to bounce around / get reset. The OS ultimately uses the Instance ID to figure out which NIC port to bind an IP address to.
Think about what happens if someone plugs 2 of your device into a system. Make sure your Instance ID is unique across all ports. You can do this by encoding into the Instance ID the PCI device serial number (if it has one) or by falling back to the PCI bus:device:function.
Don't lump together different types of hardware under the same hardware ID. For example, if the deluxe version of your device supports checksum offload, but the regular version does not -- you should use 2 different hardware IDs for these two different devices. Otherwise it gets difficult to write a single INF that has keywords for both.

A driver has enumerated two child PDO's that returned identical Device ID's

1 Answers