Question

我目前正在深入研究MSVAD简单驱动程序。不幸的是，它并没有像我希望的那样工作。当一个新程序启动时，它在C：\

下创建为STREAM_NN.WAV

不幸的是，这个文件的大小只有44个字节（只包含标题）。我附加了调试器视图并得到了这个输出：

MSVAD: [CMiniportWaveCyclic::NewStream]
MSVAD: [CMiniportWaveCyclicMSVAD::ValidateFormat]
MSVAD: [CMiniportWaveCyclic::NewStream]
MSVAD: [CMiniportWaveCyclicMSVAD::ValidateFormat]
MSVAD: CMiniportWaveCyclicMSVAD::ValidatePcm
MSVAD: [CSaveData::InitializeWorkItems]
MSVAD: [CMiniportWaveCyclicStreamMSVAD::Init]
MSVAD: SaveData 845A754C
MSVAD: [CSaveData::SetDataFormat]
MSVAD: [CSaveData::Initialize]
MSVAD: [CMiniportWaveCyclicStreamMSVAD::AllocateBuffer]
MSVAD: [CMiniportWaveCyclicStreamMSVAD::SetFormat]
MSVAD: [CSaveData::SetDataFormat]
MSVAD: New Format: 44100
MSVAD: [CMiniportWaveCyclicStreamMSVAD::SetNotificationFreq]
MSVAD: [CMiniportWaveCyclicStreamMSVAD::SetState]
MSVAD: [CMiniportWaveCyclicStreamMSVAD::SetState]
MSVAD: KSSTATE_PAUSE
MSVAD: [CMiniportWaveCyclicStreamMSVAD::SetState]
MSVAD: KSSTATE_RUN
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=480]
MSVAD: [CSaveData::WriteData ulByteCount=1284]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=628]
MSVAD: [CSaveData::WriteData ulByteCount=1136]
//Truncated for convenience
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=776]
MSVAD: [CSaveData::WriteData ulByteCount=988]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CSaveData::WriteData ulByteCount=1764]
MSVAD: [CMiniportWaveCyclicStreamMSVAD::SetState]
MSVAD: KSSTATE_PAUSE
MSVAD: [CMiniportWaveCyclicStreamMSVAD::SetState]
MSVAD: KSSTATE_STOP
MSVAD: [CSaveData::WaitAllWorkItems]
MSVAD: [CSaveData::SaveFrame]
MSVAD: [CMiniportWaveCyclicStreamMSVAD::SetState]
MSVAD: [CMiniportWaveCyclicStream::~CMiniportWaveCyclicStream]
MSVAD: [CMiniportWaveCyclicStreamMS::~CMiniportWaveCyclicStreamMS]
MSVAD: [CMiniportWaveCyclicStreamMSVAD::FreeBuffer]
MSVAD: [CSaveData::~CSaveData]

这看起来很直接，例如调用所有必要的函数。我想知道这个例子中是否存在已知错误，或者我必须考虑的任何警告？

操作系统是虚拟机中的Windows 7 32位，正常的音频播放就像魅力一样。简单驱动程序设置为默认播放设备。

Answer 1

问题是，由于方法 CSaveData :: InitializeWorkItems（savedata.cpp）中的DDK 8添加了以下几行：

if (m_pWorkItems)
{
    return ntStatus;
}

但是 CSaveData :: ~CSaveData 只释放“工作项”，而不是m_pWorkItems数组。这导致将来使用释放的“工作项目”。

要解决此问题，您需要替换 savedata.cpp，CSaveData :: InitializeWorkItems 中的代码：

if (m_pWorkItems)
{
    return ntStatus;
}

m_pWorkItems = (PSAVEWORKER_PARAM)
    ExAllocatePoolWithTag
    (
        NonPagedPool,
        sizeof(SAVEWORKER_PARAM) * MAX_WORKER_ITEM_COUNT,
        MSVAD_POOLTAG
    );

通过此代码：

if (!m_pWorkItems)
{
    m_pWorkItems = (PSAVEWORKER_PARAM)
        ExAllocatePoolWithTag
        (
            NonPagedPool,
            sizeof(SAVEWORKER_PARAM) * MAX_WORKER_ITEM_COUNT,
            MSVAD_POOLTAG
        );
}

Microsoft虚拟音频设备驱动程序示例（MSVAD）仅创建44个字节的文件

1 个答案: