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    SubjectDMAEngine and channel pairs
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    The CPU I'm working on uses two sequential DMA channels to implement
    scatter-gather. How do you handle this in the channel allocator? If
    scatter-gather is not requested the two channels work fine as normal
    DMA channels.

    So when a scatter-gather channel is requested my driver needs to fail
    the dma_alloc_chan_resources() requests until a sequential pair is
    located? Plus I need to track what channels are used in my driver so
    that I know where sequential pairs are. Is there a better way to do
    this?

    Another solution might be to statically allocate some channels as
    being scatter/gather capable and others as not being able to do it. I
    would just report fewer available channels to dmaengine and hide those
    secondary channels from it. I have 12 channels to work with.

    --
    Jon Smirl
    jonsmirl@gmail.com


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