[Mesa-dev] radeonsi: NIR - Polaris triangle sprinkling running UH SOLVED - finally

[Dieter Nützel]

Hello Marek, Timo, Nicolai,

Timo SOLVED this long-standing NIR corruption on Polaris with his 'nir: 
rewrite varying component packing' commit.

It was triggered with

commit 86b52d42368ac496fe24bc6674e754c323381635
Author: Marek Olšák <marek.olsak at amd.com>
Date:   Fri Jul 13 00:23:36 2018 -0400

     radeonsi: reduce LDS stalls by 40% for tessellation

     40% is the decrease in the LGKM counter (which includes SMEM too)
     for the GFX9 LSHS stage.

     This will make the LDS size slightly larger, but I wasn't able to 
increase
     the patch stride without corruption, so I'm increasing the vertex 
stride.

and now finally SOLVED with

commit 26aa460940f6222565ad5eb40a21c2377c59c3a6
Author: Timothy Arceri <tarceri at itsqueeze.com>
Date:   Mon Dec 10 10:23:51 2018 +1100

     nir: rewrite varying component packing

     There are a number of reasons for the rewrite.

     1. Adding support for packing tess patch varyings in a sane way.

     2. Making use of qsort allowing the code to be much easier to
        follow.

     3. Fixes a bug where different interp types caused component
        packing to be skipped for all varyings in some scenarios.

     4. Allows us to add a crude live range analysis for deciding
        which components should be packed together. This support can
        optionally be added in a future patch.

     Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>

Maybe it should backported (Cc: <mesa-stable at lists.freedesktop.org>) 
) for 19.0?

I hope my bisect help to bring some more understanding for this Polaris 
NIR bug.

Now, hunting for the (last) 19.0+ EQAA regression (DiRT Rally, black 
squares like  radv/DXVK corruption, NOT NIR related) and 'meson' OpenCL 
(Clover) build error.

Greetings,
Dieter