[Mesa-dev] i915c vs i915g piglit run

[Kenneth Graunke]

On 04/17/2013 01:59 PM, Dave Airlie wrote:
> Hi,
>
> I put a 3Ghz Core2 Q35 box i found in the office to good use (so much
> nicer than a pineview atom).
>
> http://people.freedesktop.org/~airlied/piglit/i915c/
>
> is a full run with i915c forced to advertise GL2.0 using the stub
> occlusion query hack in drirc, and i915g advertising GL2.1, and built
> against llvm 3.2.
>
> some quick regression analysis:
>
> blending regressions - fbo-blending-formats, glean blendFunc
> constant color is due to i915g advertising RGBA and BGRA support when
> the hw can't really do it, the blend color would need swizzling
> DST_ALPHA support - it seems we should smash the blend factors in this
> case to do DST_ALPHA->ONE if we have no alpha in the dst. (though the
> ALPHA* formats also seem to fail).
>
> sin/cos/tan - taylor series me more, but this could also be just
> broken as a link on irc pointed out.
>
> two-sided stencil - i915c seems to have a workaround for the hw not
> applying faces like other hw, i915g lacks this, hopefully that is the
> fix for two stencil ones
>
> array/matrix ones - i915g fails a lot of these we suspect due to
> overflowing instruction count due to inefficient GLSL/TGSI production.

But that should just fall back to software, right?

> mipmap format generation NPOT failures - no idea yet
>
> copyteximage failures - no idea yet
>
> There are others in there, but this was my quick analysis so I thought
> I would share.
>
> Dave.