Hi Tim, Yup, I meant reducing the latency! Thanks so much for replying. This is easy then :) The main issue that I am facing is that I overwrite the playback buffer with new data before my previous data has finished playing. This is what MSDN documentation says about asynchronous IO: "Do not deallocate or modify the OVERLAPPED structure or the data buffer until all asynchronous IO has been completed." Due to this, I get missing data in my audio stream. Do you have any suggestions? Thanks, Pallavi On Tue, Aug 11, 2009 at 4:49 PM, Tim Roberts <timr@xxxxxxxxx> wrote: > Pallavi Joshi wrote: > > > > I am developing an ASIO driver using kernel streaming. To increase the > > audio latency, ... > > Do you mean "decrease" the audio latency? ;) > > > ...I want to use DMA (Direct Memory Access) for communication between > > my device and my ASIO driver. In my ASIO driver, I am using the > > DeviceIoControl function with IOCTL_KS_READ_STREAM and > > IOCTL_KS_WRITE_STREAM as the control codes for reading/writing data > > from my USB audio device. Thus, I need to figure out a way which can > > operate my USB audio device in the DMA mode. Note that I am using > > kernel streaming pins here, thus there might be a way of telling the > > kernel streaming filter to operate in the DMA mode. I haven't been > > able to figure out how to do that though. > > All USB transactions use DMA. It's required by the USB host controller > specifications. > > -- > Tim Roberts, timr@xxxxxxxxx > Providenza & Boekelheide, Inc. > > ****************** > > 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/ > > -- Pallavi Joshi (480)-280-2017