[OE-core] mesa, libgbm and weston

[Denys Dmytriyenko]

On Fri, Apr 22, 2016 at 12:27:16AM +0000, Christopher Larson wrote:
> On Thu, Apr 21, 2016 at 5:06 PM Denys Dmytriyenko <denis at denix.org> wrote:
> 
> > All,
> >
> > I've been meaning to ask this for quite some time. It appears that Weston's
> > DRM compositor enabled with "kms" PACKAGECONFIG doesn't really need the
> > entire
> > mesa, but it only needs libgbm. Now, mesa in OE-Core provides libgbm as
> > one of
> > its packages, hence virtual/mesa is added in DEPENDS for kms:
> >
> > PACKAGECONFIG[kms] = "--enable-drm-compositor,--disable-drm-compositor,drm
> > udev virtual/mesa mtdev"
> >
> > On TI platforms with SGX GPU we have GLES/EGL stack (provided by
> > proprietary
> > blobs, yeah) and a separate libgbm, based on Rob Clark's
> > https://github.com/robclark/libgbm
> > Since that is enough to run Weston on our platforms, I've been carrying
> > this
> > bbappend for long time:
> >
> > PACKAGECONFIG[kms] = "--enable-drm-compositor,--disable-drm-compositor,drm
> > udev libgbm mtdev"
> >
> > It's been working fine for long time, but people keep on asking questions
> > and
> > require cleaner solution, since bbappend in a separate layer is somewhat
> > confusing. Now, the question is what is a proper solution here:
> >
> > 1. Change weston recipe in oe-core to depend on libgbm instead of
> > virtual/mesa
> > assuming that it is provided by mesa recipe and it works for other
> > platforms.
> >
> 
> I'd say this, either libgbm or virtual/libgbm.
> 
> 2. Change our libgbm recipe to declare that it PROVIDES virtual/mesa,
> > although
> > it looks like a hack and is somewhat reverse...
> >
> 
> I think the libgbm recipe would basically be lying if you do that, that
> doesn't sound ideal.

Thanks, Chris.

One other thing I was thinking is how to avoid conflict between separate 
libgbm and the one provided by mesa-gl. As mesa-gl may be useful for providing 
SW rendering for OpenGL, while leaving OpenGLES to a separate provider, like 
SGX. Unfortunately, mesa-gl also provides libgbm - would PACKAGECONFIG to use 
a standalone external libgbm work and be acceptable here?

-- 
Denys