[lkml]   [2012]   [Jan]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH] dma-buf: Use EXPORT_SYMBOL
    On Sat, Jan 21, 2012 at 11:02 PM, Daniel Vetter <> wrote:
    > On Fri, Jan 20, 2012 at 10:04:57AM -0800, Robert Morell wrote:
    >> On Wed, Jan 18, 2012 at 01:10:04AM -0800, Semwal, Sumit wrote:
    >> > On Wed, Jan 18, 2012 at 5:38 AM, Robert Morell <> wrote:
    >> > > EXPORT_SYMBOL_GPL is intended to be used for "an internal implementation
    >> > > issue, and not really an interface".  The dma-buf infrastructure is
    >> > > explicitly intended as an interface between modules/drivers, so it
    >> > > should use EXPORT_SYMBOL instead.
    >> >
    >> > + Konrad, Arnd, Mauro: there were strong objections on using
    >> > EXPORT_SYMBOL in place of EXPORT_SYMBOL_GPL by all 3 of them; I
    >> > suggest we first arrive at a consensus before merging this patch.
    >> This discussion seems to have stagnated; how do we move forward here?
    >> Sumit, as the primary author and new maintainer (congrats!) of the
    >> dma-buf infrastructure, it seems like it's really your call how to
    >> proceed.  I'd still like to see this be something that we can use from
    >> the nvidia and fglrx drivers for Xorg buffer sharing, as I and Dave have
    >> argued in this thread.  It really seems to me that this change on a
    >> technical level won't have any adverse effect on the scenarios where it
    >> can be used today, but it will allow it to be used more widely, which
    >> will prevent duplication and fragmentation in the future and be greatly
    >> appreciated by users of hardware such as Optimus.
    > Given that I've participated quite a bit in the design of dma_buf as-is,
    > let me throw in my totally irrelevant opinion, too ;-)
    > I'll refrain from comment on the actual patch, it's obviously a hot topic.
    > Furthermore I might need to ask Intel's legal dep for guidance to asses
    > things wrt my own contributions to dma_buf.
    > Otoh I'd like nvidia to be on board, especially when we're desingned
    > additions to dma_buf required to make it really work for multiple gpus. In
    > additions it looks like that the nvidia blob will only be an importer of a
    > dma_buf, at least for the use-cases discussed here.
    > So why don't you just ditch this patch here and add a small shim to your
    > blob to interface with drm's prime as an importing driver? I personally
    > would deem that acceptable and I think Dave wouldn't mind too much,
    > either.

    Hi Everyone!

    (Apologies for delay in replying; was OoO for past couple of days)

    Thanks very much for this discussion - a couple of things:

    1. I am definitely willing to make changes as needed to get as many
    devices / subsystems / frameworks to use the dma-buf infrastructure.
    This could include changing the way symbols are exported, if that is
    the *only* way to get things done.

    2. With that premise, I quite like the idea that Daniel gave (of
    course, in his capacity as one of the top contributors behind dma-buf
    infrastructure, and like he said, not as an Intel employee) - so let
    me ask the following:

    Robert, Dave,
    Technically speaking, is there no way that the EXPORT_SYMBOL_GPLed
    symbols can be used by the binary blobs, possibly with an open-sourced
    shim which provides the buffer-sharing interface to the binary blobs?
    Are there any reasons to not consider this approach?

    Also, if some of you are going to be at ELC mid-Feb at SFO, we could
    meet up face-to-face and thrash out possible ways forward.
    > Yours, Daniel
    Thanks, and best regards,
    > Disclaimer: This is my own opinion and I do not speak as an Intel employee
    > here.
    > --
    > Daniel Vetter
    > Mail:
    > Mobile: +41 (0)79 365 57 48
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2012-01-25 06:37    [W:0.028 / U:131.424 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site