[Mesa-stable] [PATCH] radv: adjust the VGT workaround for prim restart on GFX9

[Samuel Pitoiset]

On 12/11/18 8:57 PM, Marek Olšák wrote:
> It's up to you as long as you're OK with downgraded performance of 
> triangle strips with primitive restart.

I'm OK with it, at least for now. From my point of view, it's definitely 
better to avoid GPU hangs.

Bas, what's your opinion?

> 
> Marek
> 
> On Tue, Dec 11, 2018 at 10:08 AM Samuel Pitoiset 
> <samuel.pitoiset at gmail.com <mailto:samuel.pitoiset at gmail.com>> wrote:
> 
>     ping?
> 
>     After looking into this again today, I can't find any better solutions.
>     We should probably push this patch because at least two games are
>     affected. My opinion is that correctness is more important than
>     performance.
> 
>     On 10/11/18 10:42 AM, Samuel Pitoiset wrote:
>      > WD_SWITCH_ON_EOP seems to be the only workaround that fixes
>      > the GPU hangs with Yakuza and The Evil Within on Vega. I don't
>      > like as it might decrease geometry performance as pointed out
>      > by Marek, but I don't know how to implement a better one.
>      >
>      > Cc: mesa-stable at lists.freedesktop.org
>     <mailto:mesa-stable at lists.freedesktop.org>
>      > Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com
>     <mailto:samuel.pitoiset at gmail.com>>
>      > ---
>      >   src/amd/vulkan/radv_pipeline.c | 13 +++++++++++--
>      >   1 file changed, 11 insertions(+), 2 deletions(-)
>      >
>      > diff --git a/src/amd/vulkan/radv_pipeline.c
>     b/src/amd/vulkan/radv_pipeline.c
>      > index 426b417e172..2256b2c58e9 100644
>      > --- a/src/amd/vulkan/radv_pipeline.c
>      > +++ b/src/amd/vulkan/radv_pipeline.c
>      > @@ -3412,14 +3412,23 @@
>     radv_compute_ia_multi_vgt_param_helpers(struct radv_pipeline *pipeline,
>      >       }
>      >
>      >       /* Workaround for a VGT hang when strip primitive types are
>     used with
>      > -      * primitive restart.
>      > +      * primitive restart. This fixes GPU hangs with Yakuza and
>     The Evil
>      > +      * Within, at least. Not sure if we can implement a better
>     workaround.
>      >        */
>      >       if (pipeline->graphics.prim_restart_enable &&
>      >           (prim == V_008958_DI_PT_LINESTRIP ||
>      >            prim == V_008958_DI_PT_TRISTRIP ||
>      >            prim == V_008958_DI_PT_LINESTRIP_ADJ ||
>      >            prim == V_008958_DI_PT_TRISTRIP_ADJ)) {
>      > -             ia_multi_vgt_param.partial_vs_wave = true;
>      > +             if (device->physical_device->rad_info.chip_class >=
>     GFX9) {
>      > +                     /* XXX: This might decrease geometry
>     performance by 2x,
>      > +                      * but this appears to be the only
>     workaround that
>      > +                      * fixes the GPU hang.
>      > +                      */
>      > +                     ia_multi_vgt_param.wd_switch_on_eop = true;
>      > +             } else {
>      > +                     ia_multi_vgt_param.partial_vs_wave = true;
>      > +             }
>      >       }
>      >
>      >       ia_multi_vgt_param.base =
>      >
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