[lkml]   [2009]   [Jan]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH] dmatest: flush and invalidate destination buffer before DMA
    On Mon, 05 Jan 2009 18:29:56 -0700, Dan Williams <> wrote:
    > > Yes, MIPS and ARM do different thing on partial cache line. But I
    > > suppose this belongs to "implementation dependent" area of DMA API so
    > > users of the API should not depend on it. (Well, maybe I'm biased to
    > > MIPS ;-))
    > > In general, drivers must not put normal data and DMA buffer on same
    > > cacheline anyway to avoid unexpected writeback and data loss. So this
    > > ambiguity is not a problem. IMHO writeback of the partial line for
    > > DMA_FROM_DEVICE just _hides_ abusing of the DMA API and potential data
    > > loss.
    > Hmm... one implementation does the right thing in all cases.

    Yes, with additional checking in generic path :-)

    > The other silently allows data corruption unless each callsite that
    > accidentally or purposely passes cacheline-unaligned buffers adds
    > extra maintenance code. Which implementation are you biased towards
    > now? :-).

    Hmm... this is generic DMA mapping API (or linux-arch) issue. Let's
    wait comments from arch maintainers. Ralf ?

    Atsushi Nemoto

     \ /
      Last update: 2009-01-06 03:09    [W:0.021 / U:10.564 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site