[REPOST PATCH 1/8] fence: dma-buf cross-device synchronization (v17)

Daniel Vetter daniel at ffwll.ch
Thu Jun 19 12:20:50 PDT 2014


On Thu, Jun 19, 2014 at 8:19 PM, Greg KH <gregkh at linuxfoundation.org> wrote:
>> >> > EXPORT_SYMBOL_GPL()?  Same goes for all of the exports in here.
>> >> > Traditionally all of the driver core exports have been with this
>> >> > marking, any objection to making that change here as well?
>> >>
>> >> tbh, I prefer EXPORT_SYMBOL()..  well, I'd prefer even more if there
>> >> wasn't even a need for EXPORT_SYMBOL_GPL(), but sadly it is a fact of
>> >> life.  We already went through this debate once with dma-buf.  We
>> >> aren't going to change $evil_vendor's mind about non-gpl modules.  The
>> >> only result will be a more flugly convoluted solution (ie. use syncpt
>> >> EXPORT_SYMBOL() on top of fence EXPORT_SYMBOL_GPL()) just as a
>> >> workaround, with the result that no-one benefits.
>> >
>> > It has been proven that using _GPL() exports have caused companies to
>> > release their code "properly" over the years, so as these really are
>> > Linux-only apis, please change them to be marked this way, it helps
>> > everyone out in the end.
>>
>> Well, maybe that is the true in some cases.  But it certainly didn't
>> work out that way for dma-buf.  And I think the end result is worse.
>>
>> I don't really like coming down on the side of EXPORT_SYMBOL() instead
>> of EXPORT_SYMBOL_GPL(), but if we do use EXPORT_SYMBOL_GPL() then the
>> result will only be creative workarounds using the _GPL symbols
>> indirectly by whatever is available via EXPORT_SYMBOL().  I don't
>> really see how that will be better.
>
> You are saying that you _know_ companies will violate our license, so
> you should just "give up"?  And how do you know people aren't working on
> preventing those "indirect" usages as well?  :)
>
> Sorry, I'm not going to give up here, again, it has proven to work in
> the past in changing the ways of _very_ large companies, why stop now?

Dave should chime in here since currently dma-buf is _GPL and the
drm_prime.c wrapper for it is not (and he merged that one, contributed
from said $vendor). And since we're gfx people everything we do is MIT
licensed (that's where X is from after all), so _GPL for for drm stuff
really doesn't make a lot of sense for us. ianal and all that applies.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch


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