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Commit 06f10e2f authored by Vinod Koul's avatar Vinod Koul
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Documentation: dmaengine: fix the DMA_CTRL_ACK documentation 



As discussed recently the meaning of DMA_CTRL_ACK is that a desc cannot be
reused by provider until the client acknowledges receipt, i.e. has has a
chance to establish any dependency chains. So update documentation

Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
Acked-by: default avatarRobert Jarzmik <robert.jarzmik@free.fr>
parent 09659a59

Documentation/dmaengine/provider.txt

+6 −6
Original line number Diff line number Diff line
@@ -345,12 +345,12 @@ where to put them) 
      that abstracts it away.



  * DMA_CTRL_ACK

    - If set, the transfer can be reused after being completed.

    - There is a guarantee the transfer won't be freed until it is acked

      by async_tx_ack().

    - As a consequence, if a device driver wants to skip the dma_map_sg() and

      dma_unmap_sg() in between 2 transfers, because the DMA'd data wasn't used,

      it can resubmit the transfer right after its completion.

    - If clear, the descriptor cannot be reused by provider until the

      client acknowledges receipt, i.e. has has a chance to establish any

      dependency chains

    - This can be acked by invoking async_tx_ack()

    - If set, does not mean descriptor can be reused





General Design Notes

--------------------