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    SubjectPossible discrepancy regarding streaming DMA mappings in DMA-mapping.txt?
    In the explanation of streaming DMA mappings and holding onto a mapping
    for multiple DMA operations, the file Documentation/DMA-mapping.txt
    (line 507) says the following:

    If you need to use the same streaming DMA region multiple times
    and touch the data in between the DMA transfers, just map it
    with pci_map_{single,sg}, and after each DMA transfer call

    pci_dma_sync_single(dev, dma_handle, size, direction);


    pci_dma_sync_sg(dev, sglist, nents, direction);

    as appropriate.

    However, shouldn't pci_dma_sync_*() be called *before* each
    PCI_DMA_TODEVICE DMA transfer (after the CPU write, of course) and
    *after* each PCI_DMA_FROMDEVICE DMA transfer (before CPU access)? And,
    of course, before and after a "bidirectional" DMA, if appropriate.

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      Last update: 2005-03-22 13:26    [W:0.020 / U:171.776 seconds]
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