[meta-intel] [OE-core] [Patch-v2 1/1] mesa: avoid unnecessary rerunning of tasks

[Burton, Ross]

On 5 September 2013 09:33, Richard Purdie
<richard.purdie at linuxfoundation.org> wrote:
> I'd also appreciate someone (Ross maybe?) confirming that if we build
> application A against mesa, then change over to a machine that uses emgd
> and swizzle the libs around in the sysroot, do we need to recompile the
> app? This approach is assuming we do not need to do that. If we do,
> there is a different approach we need to take.

So what's happening is that we're revising the original OpenGL policy
that I posted in October last year:

http://lists.openembedded.org/pipermail/openembedded-core/2012-October/070122.html

tl;dr: I proposed that 1) we rename all GL packages so they identify
their provider (ie libgl-mesa, we do that), 2) no dependencies on
specific GL implementations, 3) only Mesa stages.  The theory was that
Mesa can be considered a canonical implementation of the various GL
platforms and that we can *build* against Mesa but *install* the right
hardware-specific GL implementation into the images.

Nice in theory and it should work, but sadly that isn't the case - the
thread has more details.  Short version is that some applications *do*
rely on specific GL headers, so you can't just swap them around in
reality.

Maybe it is time to have a mesa-gl recipe alongside mesa that *just*
builds the GL libraries.  EMGD can depend on it for the driver modules
it installs, and presumably other vendors with binary drivers can
install it for the software rendering/GLX support (Otavio etc, please
step in here!).

Ross