[Buildroot] [PATCH 1/2] package/opengl/libgbm: new virtual package

Einar Jón tolvupostur at gmail.com
Tue Nov 6 13:48:44 UTC 2018


On Mon, 5 Nov 2018 at 16:43, Thomas Petazzoni
<thomas.petazzoni at bootlin.com> wrote:
>
> Hello,
>
> On Mon, 5 Nov 2018 16:35:02 +0100, Einar Jón wrote:
>
> > I'm not much help here.
> > My only concern was building QT5 on an embedded AM335x with ti-sgx-*
> > libraries and update the kernel to 4.9 (bumping TI SDK from 2.0 to
> > 4.0).
> > There is now a kernel 4.14 (TI SDK 5.0), with only minor changes to
> > the ti-sgx-* libraries (support gbm_bo and GCC7).
> > http://www.ti.com/tool/PROCESSOR-SDK-AM335X
> >
> > kmscube seems to depend heavily on the mesa3d implementation, so I
> > don't think it's easy to make it work with the other libgbm versions.
> > Would building a working QT be a valid test of the libgbm build?
>
> Yes, it would be. So what you're saying is that the libgbm
> implementation provided by TI SGX mimics well enough the libgbm
> implementation of Mesa3D that QT5 is happy with TI SGX libgbm
> implementation ?

That's exactly what I'm saying, but currently only with a big fat
"works for me" caveat.
My company has the same CPU as the beaglebone, but our boards have
considerable HW changes.
We're using an older 3.x kernel with ti-gfx, but I have a working
build with QT 5.9 on kernel 4.9/4.14 and ti-sgx.

I'll try to throw together a minimal working set with QT tomorrow, but
I'm not sure how useful it is without a rootfs
(busybox/kernel/udev/etc).

> > Note that ti-sgx-um depends on wayland, due to a library dependency on
> > libwayland-server.so.0 and libwayland-client.so.0  (see ldd libpvrs_WAYLAND.so)
> > So the dropped dependency to wayland in ti-sgx-libgbm should have been
> > on ti-sgx-um.
> > Without it, QT5 will not find any EGL backend.
> >
> > So the ti-sgx-um should be adding
> > select BR2_PACKAGE_WAYLAND
> > select BR2_PACKAGE_HAS_LIBEGL_WAYLAND
>
> ACK.
>
> > That way Qt5 can build with a valid EGL backend, using ti-sgx instead
> > of the ancient ti-gfx.
> > But this does nothing to help build kmscube.
>
> Right. I'm still confused by this libgbm thing though, where everyone
> seems to have its own implementation, but there is no common API
> implemented by everybody.

So am I. The ti-sgx-libgbm repo seems to be maintained by ti.com, but
there seems to be no real effort into making it more than just the
bare minimum to use ti-sgx-um.

-- 
Regards
Einar Jón


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