Bug#793111: OpenGL ES2 support does not work with OpenGL support enabled

[Manuel A. Fernandez Montecelo]

2015-10-22 13:58 GMT+01:00 Prof. Dr. Gundolf Kiefer
<Gundolf.Kiefer at hs-augsburg.de>:
> Hello Manuel,
>
> I understand well that splitting the package is not ideal.
>
>> It looks to me that this is a problem that would be better solved
>> upstream, not only for Debian (and derivatives).  If there's a problem
>> that can be solved while having the two backends it would be ideal,
>> otherwise the code on that platform(*) should disable support for the
>> backends which do not work properly, and not claim to support that
>> renderer.
>>
>> (*) Or, perhaps it works in general in armhf, but not on that
>> particular hardware.
>
> The status as I observed is that both backends work. But on armhf,
> OpenGL ES2 only works, if OpenGL (whithout 'ES2') is disabled during
> compilation. My hardware (A20 SoC with Mali 400) only supports
> OpenGl ES2, and this may be the case for many ARM-based systems.
>
> Hence, disabling OpenGl (without 'ES2') for armhf may be a good
> temporary solution. (I hope nobody kills me for this suggestion.)

It's not a bad suggestion in general, but from experience:

- often, what starts as temporary ends up being permanent/for years,
until somebody reviews it, and specially if there are no new releases
upstream for years (as it has been the case)

- it's not clear to me if this applies mostly to that particular
hardware or to all armhf or arm in general, or maybe even it should be
done on all arches except a few (intel/amd) -- because many other
arches, like mips*, can have the same issue if the GLES is prefered

- also often, when we apply some fix and it's not fixed and released
upstream, people start to depend on that behaviour in Debian and
derivatives, at some point getting to stable releases, so when we
revert to the default behaviour there are problems and complaints
again (or there are complaints that "SDL in Debian is broken and all
other distros get it right, don't use Debian")

So it's a bit of a dangerous spot to get into.


> I have not tested unreleased upstream code yet. Who would be the best
> person to contact about this issue upstream?

I don't know if there a other ways to contact at libsdl.org, but the
bugzillla is probably the best place.  Sometimes they reply quickly,
sometimes they don't.

If they manage to fix it or change the behaviour, please ask them to
also do a new release, so we can refer to a clear point in time rather
than picking random patches or VCS at random dates.


Cheers.
-- 
Manuel A. Fernandez Montecelo <manuel.montezelo at gmail.com>