[Mesa-dev] [PATCH] i965: Fix ARB_indirect_parameters logic.

[Manolova, Plamena]

Thank you for helping me out with this Ken!

On Tue, Oct 31, 2017 at 3:50 AM, Kenneth Graunke <kenneth at whitecape.org>
wrote:

> On Monday, October 30, 2017 2:14:24 PM PDT Plamena Manolova wrote:
> > This patch modifies the ARB_indirect_parameters logic in
> > brw_draw_prims, so that our implementation isn't affected if
> > another application attempts to use predicates. Previously we
> > were using a predicate with a DELTAS_EQUAL comparison operation
> > and relying on the MI_PREDICATE_DATA register being 0. Our code
> > to initialize MI_PREDICATE_DATA to 0 was incorrect, so we were
> > accidentally using whatever value was written there. Because the
> > kernel does not initialize the MI_PREDICATE_DATA register on
> > hardware context creation, we might inherit the value from whatever
> > context was last running on the GPU (likely another process).
> > The Haswell command parser also does not currently allow us to write
> > the MI_PREDICATE_DATA register. Rather than fixing this and requiring
> > an updated kernel, we switch to a different approach which uses a
> > SRCS_EQUAL predicate that makes no assumptions about the states of any
> > of the predicate registers.
> >
> > Fixes: piglit.spec.arb_indirect_parameters.tf-count-arrays
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103085
> >
> > Signed-off-by: Plamena Manolova <plamena.manolova at intel.com>
>
> Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
>
> and pushed.  Thanks Pam!
>
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