[Mesa-dev] i915c vs i915g piglit run

Dave Airlie airlied at gmail.com
Wed Apr 17 13:59:10 PDT 2013


I put a 3Ghz Core2 Q35 box i found in the office to good use (so much
nicer than a pineview atom).


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.

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.


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