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    SubjectRe: [Linaro-mm-sig] [RFC 1/2] dma-buf: Introduce dma buffer sharing mechanism
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    On Sat, Nov 26, 2011 at 8:00 AM, Daniel Vetter <daniel@ffwll.ch> wrote:
    > On Fri, Nov 25, 2011 at 17:28, Dave Airlie <airlied@gmail.com> wrote:
    >> I've rebuilt my PRIME interface on top of dmabuf to see how it would work,
    >>
    >> I've got primed gears running again on top, but I expect all my object
    >> lifetime and memory ownership rules need fixing up (i.e. leaks like a
    >> sieve).
    >>
    >> http://cgit.freedesktop.org/~airlied/linux/log/?h=drm-prime-dmabuf
    >>
    >> has the i915/nouveau patches for the kernel to produce the prime interface.
    >
    > I've noticed that your implementations for get_scatterlist (at least
    > for the i915 driver) doesn't return the sg table mapped into the
    > device address space. I've checked and the documentation makes it
    > clear that this should be the case (and we really need this to support
    > certain insane hw), but the get/put_scatterlist names are a bit
    > misleading. Proposal:
    >
    > - use struct sg_table instead of scatterlist like you've already done
    > in you branch. Simply more consistent with the dma api.

    yup

    > - rename get/put_scatterlist into map/unmap for consistency with all
    > the map/unmap dma api functions. The attachement would then serve as
    > the abstract cookie to the backing storage, similar to how struct page
    > * works as an abstract cookie for dma_map/unmap_page. The only special
    > thing is that struct device * parameter because that's already part of
    > the attachment.

    yup

    > - add new wrapper functions dma_buf_map_attachment and
    > dma_buf_unmap_attachement to hide all the pointer/vtable-chasing that
    > we currently expose to users of this interface.

    I thought that was one of the earlier comments on the initial dmabuf
    patch, but either way: yup

    BR,
    -R

    > Comments?
    >
    > Cheers, Daniel
    > --
    > Daniel Vetter
    > daniel.vetter@ffwll.ch - +41 (0) 79 364 57 48 - http://blog.ffwll.ch
    > --
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