typedef struct _PNP_DEVICE_COMPLETION_QUEUE
{
     ULONG SpinLock;
     ULONG DispatchedCount;
     LIST_ENTRY DispatchedList;
     KSEMAPHORE CompletedSemaphore;
     LIST_ENTRY CompletedList;
} PNP_DEVICE_COMPLETION_QUEUE, *PPNP_DEVICE_COMPLETION_QUEUE;

Windows Vista Kernel Structures