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

[Marek Olšák]

On Thu, Oct 11, 2018 at 4:43 AM Samuel Pitoiset
<samuel.pitoiset at gmail.com> 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
> Signed-off-by: Samuel Pitoiset <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)) {

Adjacency primitive types should already have wd_switch_on_eop set to true.

The workaround I'm going to use is:

        if (!wd_switch_on_eop && key->u.primitive_restart)
            partial_vs_wave = true;

Our docs say we should do this. I don't know why it still hangs with
this workaround.

Marek