[Mesa-dev] [PATCH 2/2] i965: Implement ARB_indirect_parameters

Bas Nieuwenhuizen bas at basnieuwenhuizen.nl
Thu Aug 31 17:45:53 UTC 2017

On Wed, Aug 30, 2017, at 14:59, Ilia Mirkin wrote:
> On Wed, Aug 30, 2017 at 3:17 AM, Bas Nieuwenhuizen
> <bas at basnieuwenhuizen.nl> wrote:
> > So as a random drive-by review, I think the risk in this implementation
> > is that apps just set maxdrawcount to some high value . If I'm reading
> > the spec correctly there is no real bound on the value except for the
> > max-representable value for the integer.  Also AFAIK the AMD and NVidia
> > implementation don't really get slower if you specify maxdrawcount very
> Can't speak for AMD, but this is actually extremely similar (in
> principle) to how this is handled on NVIDIA. It's a little cleaner
> since there's a nice macro, but since macros can't have a variable
> number of arguments, you have to feed it maxdrawcount args. Admittedly
> this is the nouveau impl, but I'm almost certain that the blob does it
> in a similar way.

I thought, you had a macro that looped, but seems that was a
misunderstanding on my side.  If nvidia does it that way, then I suppose
there is little risk of games expecting something more efficient. Never
mind my comments then.

> > large, so I wouldn't be surprised if a good number of apps would set the
> > maxdrawcount really high, like MAX_INT or something. I suspect you
> > wouldn't want to emit that .
> Let's hope not!
>   -ilia

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