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    SubjectRe: dma_unmap_single() lacking cache sync on some archs?
    [Resending with CC to affected parties]

    Hi,

    I would expect cache synchronization for DMA_TO_DEVICE and DMA_BIDIRECTIONAL
    when dma_map_single() is called, and for DMA_FROM_DEVICE and DMA_BIDIRECTIONAL
    when dma_unmap_single() is called.

    However, on some architechtures (at least avr32, blackfin, ...), cache
    synchronization only happens when dma_map_single() is called (and then
    irrespective of DMA direction). dma_unmap_single() is a no-op for these archs.

    See e.g. http://lxr.linux.no/#linux+v3.0.4/arch/avr32/include/asm/dma-mapping.h#L117

    Isn't this a bug?

    (Please CC me in responses.)

    --
    Arvid Brodin
    Enea Services Stockholm AB



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