Cross-regressions between wine and mesa: how to handle them?

[Henri Verbeet]

On 30 January 2014 22:22, Stefan Dösinger <stefandoesinger at gmail.com> wrote:
> I don't know about the extend this card support pixel shaders. There
> may be a way for the driver and/or wine to work without falling back
> to software. But overall I disagree with the premise of this patch.
> There's a point in shipping a < GL 2.0 driver for hardware that just
> doesn't support GL 2.0. But there is no point in requiring the
> application to magically know if the driver's GL 2.0 is really 2.0 or
> just something rigged with software fallback mines.
>
> Can you file a Mesa bug about this issue? I think we should ask the
> Mesa devs about their opinion.
>
I don't know if that's specifically the issue here, but GL 2.0 also
introduced point sprite coordinate origin switching. We need that when
rendering offscreen, and I seem to recall i915 hitting a software
fallback for that. Without GL 2.0 we'd just render incorrectly
instead. It should be easy enough to rule that out by commenting out
the "glPointParameteriNV(GL_POINT_SPRITE_COORD_ORIGIN, origin);" call
in psorigin(). It's also generally useful to set INTEL_DEBUG=perf when
investigating these kinds of things.