usb驱动问题！！！dispatch_level在callusbdi下不可用！！急急急！！

andy211457

usb驱动问题！！！dispatch_level在callusbdi下不可用！！急急急！！ [复制链接]

callusbdi windows wdm设备驱动程序开发指南（chris cant） 在dispatch_level调用出现死等，但是在passive_level正常
书上也说只能在Passive_level调用，是什么原因呢，怎样才能在dispatch_level调用呢？
高手快来啊
NTSTATUS CallUSBDI(IN PDEVICE_EXTENSION dx,IN PVOID UrbEtc,
                                   IN ULONG IoControlCode,
                                   IN ULONG Arg2)
{
        IO_STATUS_BLOCK IoStatus;
        KEVENT event;
        PIRP Irp;
        PIO_STACK_LOCATION NextIrpStack;
        NTSTATUS status;
        KeInitializeEvent(&event,NotificationEvent,FALSE);

        Irp=IoBuildDeviceIoControlRequest(IoControlCode,
                dx->NextLowerDriver,
                NULL,
                0,
                NULL,
                0,
                TRUE,
                &event ,
                &IoStatus);
        NextIrpStack=IoGetNextIrpStackLocation(Irp);
        NextIrpStack->Parameters.Others.Argument1=UrbEtc;
        NextIrpStack->Parameters.Others.Argument2=(PVOID)Arg2;
        status=IoCallDriver(dx->NextLowerDriver,Irp);
        if(status==STATUS_PENDING)
        {
                DebugPrint(("CallUSBDI: wait for URB completion"));

                status=KeWaitForSingleObject(&event,Suspended,KernelMode,FALSE,NULL);
                status=IoStatus.Status;
        }
        DebugPrint(("CallUSBDI returned >x",status));
        return status;
}

pauline_o

没有高手啊，自己顶啊。。。

dmhy

专家在哪里啊，不够可以加分啊

33love

I am not sure if you can call IoBuildDeviceIoControlRequest in DISPATCH_LEVEL. The functions is invoked in IRQL <= APC_LEVEL as wdk document describing, if current IRQL is higher than APC_LEVEL, the result may be unexpectable. I guess some dead lock happend in your case.
Actually, you can allocate your Irp using IoAllocatIrp and send it to bus in DISPATCH_LEVEL, but you should not wait in this level too because it is also not safe. Try to assign workitem for your job and invoke 'CallUSBDI' in the workitem process routine.

xuchenglong

KeWaitForSingleObject只有在(Timeout != NULL && *Timeout == 0)时才能在DISPATCH_LEVEL下调用。