[Mesa-dev] [PATCH] i965: Use software primitive restart when transform feedback active.

[Paul Berry]

On 6 April 2013 20:25, Paul Berry <stereotype441 at gmail.com> wrote:

> When transform feedback is active, the driver manually counts the
> number of primitives that run through the pipeline, so that if a batch
> buffer flush happens, the next batch buffer can pick up transform
> feedback where the last batch buffer left off.  Hardware-accelerated
> primitive restart interferes with this process (because it makes the
> primitive count depend not just on the number of vertices entering the
> pipeline, but also on the contents of the index buffer).  So, when
> transform feedback is active, we need to fall back to the software
> implementation of primitive restart.
>
> Fixes piglit test "spec/!OpenGL 3.1/primitive-restart-xfb flush".
>
> NOTE: This is a candidate for stable release branches.
>

NAK this patch.  Eric Anholt came up with a much better solution that
doesn't require a software fallback (commits 007a88e and 62a18da).
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