[Mesa-dev] [PATCH 2/2] egl: add EGL_platform_device support

[Mathias Fröhlich]

Hi Emil,

On Monday, 8 April 2019 12:28:55 CEST Emil Velikov wrote:
> > Now that I have been putting together a test case for the the actual use
> > I do see some issues with the pbuffer code path. Well - still investigating
> > if the test is wrong or the result.
> >
> Actually I do recall some issues with surfaceless (which is
> practically identical to this code) and some (with alpha?) formats.
> My memory is pretty flaky - I would suggest trying various configs:
> with, w/o alpha, 32/24 etc.

Ok, yesterday evening I spent some time to look into that.
Finally the egl config mechanism puts double buffer visuals
to the pbuffer surface which in turn makes mesa think if should look
at the back buffer which is in turn not set in the pbuffer gl_framebuffer.
That one makes my drivers just throw away the rendering result so a
read back does not show anything usable.

With that fixed I get in principle correct results.

My gitlab repo contains a branch that sketches my quick fix that I use to make
at least the new piglit test case work. No further testing done.
But may be that helps in getting something reasonable out.

best

Mathias