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KMDF DMA problem RRS feed

  • Question

  • Hi,

    I'm working on the windows driver for our FPGA based PCIe board.

    A have problem with implemet DMA. It works only if the transfer can fit into one DMA operation. Then WdfDmaTransactionDmaCompleted returns TRUE (in InterruptDpc) and transfer completes, the data are ok. However, if the transfer is larger and the operation is stagged, InterruptDpc is interrupted and WdfDmaTransactionDmaCompleted immediately call programDMA callback,  with SGlist parametrs (addresses) is same as first operation.

    Thank you

    Wednesday, July 2, 2014 12:47 PM

All replies

  • Can you please clarify what the problem is? Due to buffer bouncing getting the same address in your EvtProgramDma may not necessarily be in indication of an error.

    Please note that due to buffer bouncing your DMA data would not be available until the DMA transaction is complete.


    pg - This posting is provided "AS IS" with no warranties, and confers no rights.

    Wednesday, July 2, 2014 7:31 PM
  • post your code

    d -- This posting is provided "AS IS" with no warranties, and confers no rights.

    Wednesday, July 2, 2014 10:42 PM