[Mesa-dev] [PATCH 1/4] radv: move emitting VGT_GS_MODE into the HW VS path

[Bas Nieuwenhuizen]

On Wed, Jul 17, 2019 at 3:44 PM Samuel Pitoiset
<samuel.pitoiset at gmail.com> wrote:
>
> It's useless for NGG anyways.
>
> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
> ---
>  src/amd/vulkan/radv_pipeline.c | 43 ++++++++++++++++++++++++++--------
>  1 file changed, 33 insertions(+), 10 deletions(-)
>
> diff --git a/src/amd/vulkan/radv_pipeline.c b/src/amd/vulkan/radv_pipeline.c
> index fdeb31c453e..686fd371f0f 100644
> --- a/src/amd/vulkan/radv_pipeline.c
> +++ b/src/amd/vulkan/radv_pipeline.c
> @@ -3272,27 +3272,18 @@ radv_pipeline_generate_vgt_gs_mode(struct radeon_cmdbuf *ctx_cs,

Can you rename the function?


>                 pipeline->shaders[MESA_SHADER_TESS_EVAL] :
>                 pipeline->shaders[MESA_SHADER_VERTEX];
>         unsigned vgt_primitiveid_en = 0;
> -       uint32_t vgt_gs_mode = 0;
>
> -       if (radv_pipeline_has_gs(pipeline)) {
> -               const struct radv_shader_variant *gs =
> -                       pipeline->shaders[MESA_SHADER_GEOMETRY];
> -
> -               vgt_gs_mode = ac_vgt_gs_mode(gs->info.gs.vertices_out,
> -                                            pipeline->device->physical_device->rad_info.chip_class);
> -       } else if (radv_pipeline_has_ngg(pipeline)) {
> +       if (radv_pipeline_has_ngg(pipeline)) {
>                 bool enable_prim_id =
>                         outinfo->export_prim_id || vs->info.info.uses_prim_id;
>
>                 vgt_primitiveid_en |= S_028A84_PRIMITIVEID_EN(enable_prim_id) |
>                                       S_028A84_NGG_DISABLE_PROVOK_REUSE(enable_prim_id);
>         } else if (outinfo->export_prim_id || vs->info.info.uses_prim_id) {
> -               vgt_gs_mode = S_028A40_MODE(V_028A40_GS_SCENARIO_A);
>                 vgt_primitiveid_en |= S_028A84_PRIMITIVEID_EN(1);
>         }
>
>         radeon_set_context_reg(ctx_cs, R_028A84_VGT_PRIMITIVEID_EN, vgt_primitiveid_en);
> -       radeon_set_context_reg(ctx_cs, R_028A40_VGT_GS_MODE, vgt_gs_mode);
>  }
>
>  static void
> @@ -3370,6 +3361,38 @@ radv_pipeline_generate_hw_vs(struct radeon_cmdbuf *ctx_cs,
>                                cull_dist_mask << 8 |
>                                clip_dist_mask);
>
> +       /* We always write VGT_GS_MODE in the VS state, because every switch
> +        * between different shader pipelines involving a different GS or no GS
> +        * at all involves a switch of the VS (different GS use different copy
> +        * shaders). On the other hand, when the API switches from a GS to no
> +        * GS and then back to the same GS used originally, the GS state is not
> +        * sent again.
> +        */
> +       unsigned vgt_gs_mode;
> +       if (!radv_pipeline_has_gs(pipeline)) {
> +               const struct radv_vs_output_info *outinfo =
> +                       get_vs_output_info(pipeline);
> +               const struct radv_shader_variant *vs =
> +                       pipeline->shaders[MESA_SHADER_TESS_EVAL] ?
> +                       pipeline->shaders[MESA_SHADER_TESS_EVAL] :
> +                       pipeline->shaders[MESA_SHADER_VERTEX];
> +               unsigned mode = V_028A40_GS_OFF;
> +
> +               /* PrimID needs GS scenario A. */
> +               if (outinfo->export_prim_id || vs->info.info.uses_prim_id)
> +                       mode = V_028A40_GS_SCENARIO_A;
> +
> +               vgt_gs_mode = S_028A40_MODE(mode);
> +       } else {
> +               const struct radv_shader_variant *gs =
> +                       pipeline->shaders[MESA_SHADER_GEOMETRY];
> +
> +               vgt_gs_mode = ac_vgt_gs_mode(gs->info.gs.vertices_out,
> +                                            pipeline->device->physical_device->rad_info.chip_class);
> +       }
> +
> +       radeon_set_context_reg(ctx_cs, R_028A40_VGT_GS_MODE, vgt_gs_mode);
> +

Can you keep this in a separate function (possibly with the name
radv_pipeline_generate_vgt_gs_mode)?
>         if (pipeline->device->physical_device->rad_info.chip_class <= GFX8)
>                 radeon_set_context_reg(ctx_cs, R_028AB4_VGT_REUSE_OFF,
>                                        outinfo->writes_viewport_index);
> --
> 2.22.0
>
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