[Mesa-dev] [RFC PATCH 1/2] r600/sb: Set flags for GROUP_BARRIER instruction and force it into slot X

[Gert Wollny]

Am Mittwoch, den 10.01.2018, 15:27 -0500 schrieb Ilia Mirkin:
[...]
> 
> If your hardware executes all the vertices in parallel, then a
> barrier should be unnecessary.

My first try for this patch did not include forcing the barrier into
slot x, which in turn resulted in failing piglits, e.g.

   tcs-output-array-float-index-rd-after-barrier

and I'm quite confident that the LDS r/w order was not broken - also
because just forcing the barrier into slot x fixed it, so I guess not
all vertices are always processed in parallel, which is also no
surprise since the number of shader units attributed to the TCS stage
is limited.

Best, 
Gert