[Mesa-dev] GPL'd vl_mpeg12_bitstream.c

[Christian König]

Am Freitag, den 12.08.2011, 10:49 -0400 schrieb Younes Manton:
> Sorry, by incompatible I didn't mean that you couldn't use them
> together, but that one is more restrictive than the other. Like the
> discussion you quoted states, if you combine MIT and GPL you have to
> satisfy both of them, which means you have to satisfy the GPL. I
> personally don't care that much, but unfortunately with the way
> gallium is built it affects more than just VDPAU.
> 
> Every driver in lib/gallium includes that code, including swrast_dri
> (softpipe), r600_dri, etc, and libGL loads those drivers. If you build
> with the swrast config instead of DRI I believe galllium libGL
> statically links with softpipe, so basically my understanding is that
> anyone linking with gallium libGL (both swrast and DRI configs) has to
> satisfy the GPL now.
A crap, your right. I've forgotten that GPL has even a problem when code
is just linked in, compared to being used.

> Maybe someone else who is more familiar with these sorts of things can
> comment and confirm that this is accurate and whether or not it's a
> problem.
I already asked around in my AMD team, and the general answer was: Oh
fuck I've no idea, please don't give me a headache. I could asked around
a bit more, but I don't think we get a definitive answer before xmas.

As a short term solution we could compile that code conditionally, and
only enable it when the VDPAU state tracker is enabled. But as the long
term solution the code just needs a rewrite, beside having a license
problem, it is just not very optimal. The original code is something
like a decade old, and is using a whole bunch of quirks which are not
useful by today’s standards (not including the sign in mv tables for
example). ffmpegs/libavs implementation for example is something like
halve the size and even faster, but uses more memory for table lookups.
But that code is also dual licensed under the GPL/LGPL.

Using LGPL code instead could also be a solution, because very important
parts of Mesa (the GLSL parser for example) is already licensed under
that, but I'm also not an expert with that also.

Christian.