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

[Otavio Salvador]

On Thu, Sep 5, 2013 at 5:33 AM, Richard Purdie
<richard.purdie at linuxfoundation.org> wrote:
....
> This also raises some other questions. The existing code in meta-intel
> adds EMGD into the DEPENDS. It does this so the normal PROVIDES for
> virtual/libgl and friends don't have to change. It does mean the sstate
> checksums for anything depending on mesa change however. If we don't
> have the dependency, things may try and build before emgd is built,
> libGL would be missing and things would break.
>
> So somehow we need to add in the dependency let leave the sstate
> checksums unchanged. This is possible in the sstate checksum validation
> code but its probably easiest to change that in the core, not
> meta-intel :/.
>
> 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.

In theory both cases are possible; the API must be the same but we
cannot guarantee ABI will match.

> So in summary, this problem is far from simple, we do have most of the
> pieces we need to fix it with some tweaking but some of the changes are
> invasive and might need to be deferred to 1.6. As it stands, the change
> will cause issues due to the changed DEPENDS. We do need to think
> carefully about this and solve it once and for all in a way which works
> optimally but the existing workaround might be best until we can pull
> all the better pieces together.
>
> I hope this was a relatively clear explanation of the problem, let me
> know if I need to clarify anything. I've cc'd OE-Core since I think more
> people probably need to see/think about this.

We have same issues in meta-fsl-arm; there we made mesa and gpu
packages machine specific as we /mangle/ them.

-- 
Otavio Salvador                             O.S. Systems
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