usb插拔,IRP_MN_SURPRISE_REMOVAL与IRP_MN_REMOVE_DEVICE该如何处理


USB的URB数据循环如下：

NTSTATUS IsoStreamTransferComplete(
IN PDEVICE_OBJECT bunkfdo,
IN PIRP Irp,
IN PVOID Context
)
{
……
IoSetCompletionRoutine(Irp,
IsoStreamTransferComplete,
transferObject,
TRUE,
TRUE,
TRUE);
if (Working == pdx->DeviceState)
status = IoCallDriver(pdx->StackDeviceObject,Irp);

……
}


当USB设备意外被拔下时：
NTSTATUS USB_DispatchPnp(
   IN PDEVICE_OBJECT fdo,
   IN PIRP           Irp
   )
{
    ……
    case IRP_MN_SURPRISE_REMOVAL:
    {
        KeAcquireSpinLock(&pdx->DevStateLock, &oldIrql);
        SET_NEW_PNP_STATE(pdx, SurpriseRemoved);
        KeReleaseSpinLock(&pdx->DevStateLock, oldIrql);

        ntStatus = USB_DefaultPnpHandler(fdo, Irp);
    }
    break;

    case IRP_MN_REMOVE_DEVICE:
    {
        KeAcquireSpinLock(&pdx->DevStateLock, &oldIrql);
        SET_NEW_PNP_STATE(pdx, Removed);
        KeReleaseSpinLock(&pdx->DevStateLock, oldIrql);

        for (i = 0; i < pdx->Interface->NumberOfPipes; i++)
        {
            USB_AbortPipe(fdo,(USBD_PIPE_HANDLE) pdx->Interface->Pipes[i].PipeHandle);
        }

        UnlockDevice(fdo); // once for LockDevice at start of dispatch
        UnlockDevice(fdo); // once for initialization during AddDevice

        KeWaitForSingleObject(&pdx->evRemove, Executive, KernelMode, FALSE, NULL);

        if (pdx->DeviceDescriptor)
        {
                ExFreePool(pdx->DeviceDescriptor);
        }

        if (pdx->Interface != NULL)
        {
                ExFreePool(pdx->Interface);
        }

        if (pdx->NeedCleanup)
        {
                UNICODE_STRING deviceLinkUnicodeString;

                pdx->NeedCleanup = FALSE;

                RtlInitUnicodeString (&deviceLinkUnicodeString,
                pdx->DeviceLinkNameBuffer);

                IoDeleteSymbolicLink(&deviceLinkUnicodeString);
        }

        IoDetachDevice(pdx->StackDeviceObject);

        IoDeleteDevice (fdo);

        ntStatus = USB_DefaultPnpHandler(fdo, Irp);
    }
    break; 
    ……
}


运行时，拔下USB设备：
有时候PC正常运行，再次插上USB设备，设备能够恢复正常工作。
有时候PC卡死（无法响应鼠标键盘操作）

请问程序中IRP_MN_SURPRISE_REMOVAL与IRP_MN_REMOVE_DEVICE哪里处理不当？