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Storage Class Driver's AddDevice Routine

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The PnP manager calls a storage class driver's AddDevice routine when it detects a device controlled by that driver. A storage class driver's AddDevice routine:

  • Claims the device as described in Storage Class Driver's ClaimDevice Routine, or, if the driver is unable to claim the device, returns STATUS_SUCCESS.

  • If the driver successfully claims the device, creates a device object (FDO).

  • Registers device interfaces that applications and other system devices can use. The class driver enables such interfaces when it receives a PnP start request.

  • Prepares the device object to handle a start request as described in Writing an AddDevice Routine.

  • Attaches the device object to the device stack by calling IoAttachDeviceToDeviceStack with the input PDO.

  • If the device starts in a known power state, calls PoSetPowerState.

  • Clears the DO_DEVICE_INITIALIZING flag on the new device object.

A storage class driver stores the pointer returned by IoAttachDeviceToDeviceStack in the device extension of its own device object (FDO) that represents the newly claimed device, and must use this pointer in all subsequent requests that the class driver sends to the next-lower driver. The driver also stores the pointer to the input PDO in the device extension, but after IoAttachDeviceToDeviceStack returns the driver must use the pointer to the input PDO only in calls to PnP IoXxx routines that take such a pointer as a parameter.

For more information, see Writing an AddDevice Routine.