Hello swapnil, > So how can I avoid these DMA related code. like > 1. It requires AdapterObject. In 32-bit systems, AdapterObject is emulated by Windows HAL so you don't need to implement your own. But in 64-bit systems, there is no emulation and you must implement IRP_MJ_PNP/IRP_MN_QUERY_INTERFACE handler for GUID_BUS_INTERFACE_STANDARD interface. > 2. In RevokeMappings() implementation we need index of stBDList. Mapping indexes are a common WavePci property, you assign them yourself by calling to GetMapping (). Regards, Eugene ****************** WDMAUDIODEV addresses: Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx URL to WDMAUDIODEV page: http://www.wdmaudiodev.com/