enum ACP_MESSAGE_TYPE    
{  
    ACP_MESSAGE_TYPE_AUDIO_FRAME_START = 0x01,  
    ACP_MESSAGE_TYPE_FLOWGRAPH_COMPLETED = 0x02,  
    ACP_MESSAGE_TYPE_SRC_BLOCKED = 0x04,  
    ACP_MESSAGE_TYPE_DMA_BLOCKED = 0x08,  
    ACP_MESSAGE_TYPE_COMMAND_COMPLETED = 0x10,  
    ACP_MESSAGE_TYPE_FLOWGRAPH_TERMINATED = 0x20,  
    ACP_MESSAGE_TYPE_ERROR = 0x40,  
    ACP_MESSAGE_TYPE_DISCONNECTED = 0x80,  
    ACP_MESSAGE_TYPE_MASK = 0xff  
}