[Mesa-dev] [PATCH 6/6] radeonsi: fix gl_BaseVertex in non-indexed draws

Marek Olšák maraeo at gmail.com
Wed Apr 12 15:43:50 UTC 2017


For the series:

Reviewed-by: Marek Olšák <marek.olsak at amd.com>

Marek

On Wed, Apr 12, 2017 at 11:20 AM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
> From: Nicolai Hähnle <nicolai.haehnle at amd.com>
>
> gl_BaseVertex is supposed to be 0 in non-indexed draws. Unfortunately, the
> way they're implemented, the VGT always generates indices starting at 0,
> and the VS prolog adds the start index.
>
> There's a VGT_INDX_OFFSET register which causes the VGT to start at a
> driver-defined index. However, this register cannot be written from
> indirect draws.
>
> So fix this unlikely case by setting a bit to tell the VS whether the
> draw is indexed or not, so that gl_BaseVertex can be adjusted accordingly
> when used.
>
> Fixes a bug in
> KHR-GL45.shader_draw_parameters_tests.ShaderMultiDrawArraysParameters.*
> ---
>  src/gallium/drivers/radeonsi/si_shader.c     | 17 +++++++++++++++--
>  src/gallium/drivers/radeonsi/si_shader.h     |  2 ++
>  src/gallium/drivers/radeonsi/si_state_draw.c |  8 ++++++--
>  3 files changed, 23 insertions(+), 4 deletions(-)
>
> diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
> index 02447dd..f1daebe 100644
> --- a/src/gallium/drivers/radeonsi/si_shader.c
> +++ b/src/gallium/drivers/radeonsi/si_shader.c
> @@ -1394,23 +1394,36 @@ static void declare_system_value(struct si_shader_context *ctx,
>                                                   SI_PARAM_BASE_VERTEX), "");
>                 break;
>
>         case TGSI_SEMANTIC_VERTEXID_NOBASE:
>                 /* Unused. Clarify the meaning in indexed vs. non-indexed
>                  * draws if this is ever used again. */
>                 assert(false);
>                 break;
>
>         case TGSI_SEMANTIC_BASEVERTEX:
> -               value = LLVMGetParam(ctx->main_fn,
> -                                    SI_PARAM_BASE_VERTEX);
> +       {
> +               /* For non-indexed draws, the base vertex set by the driver
> +                * (for direct draws) or the CP (for indirect draws) is the
> +                * first vertex ID, but GLSL expects 0 to be returned.
> +                */
> +               LLVMValueRef vs_state = LLVMGetParam(ctx->main_fn, SI_PARAM_VS_STATE_BITS);
> +               LLVMValueRef indexed;
> +
> +               indexed = LLVMBuildLShr(gallivm->builder, vs_state, ctx->i32_1, "");
> +               indexed = LLVMBuildTrunc(gallivm->builder, indexed, ctx->i1, "");
> +
> +               value = LLVMBuildSelect(gallivm->builder, indexed,
> +                                       LLVMGetParam(ctx->main_fn, SI_PARAM_BASE_VERTEX),
> +                                       ctx->i32_0, "");
>                 break;
> +       }
>
>         case TGSI_SEMANTIC_BASEINSTANCE:
>                 value = LLVMGetParam(ctx->main_fn,
>                                      SI_PARAM_START_INSTANCE);
>                 break;
>
>         case TGSI_SEMANTIC_DRAWID:
>                 value = LLVMGetParam(ctx->main_fn,
>                                      SI_PARAM_DRAWID);
>                 break;
> diff --git a/src/gallium/drivers/radeonsi/si_shader.h b/src/gallium/drivers/radeonsi/si_shader.h
> index fdb0dd4..f145eab 100644
> --- a/src/gallium/drivers/radeonsi/si_shader.h
> +++ b/src/gallium/drivers/radeonsi/si_shader.h
> @@ -213,20 +213,22 @@ enum {
>         SI_PARAM_BLOCK_ID,
>         SI_PARAM_THREAD_ID,
>
>         SI_NUM_PARAMS = SI_PARAM_POS_FIXED_PT + 9, /* +8 for COLOR[0..1] */
>  };
>
>  /* Fields of driver-defined VS state SGPR. */
>  /* Clamp vertex color output (only used in VS as VS). */
>  #define S_VS_STATE_CLAMP_VERTEX_COLOR(x)       (((unsigned)(x) & 0x1) << 0)
>  #define C_VS_STATE_CLAMP_VERTEX_COLOR          0xFFFFFFFE
> +#define S_VS_STATE_INDEXED(x)                  (((unsigned)(x) & 0x1) << 1)
> +#define C_VS_STATE_INDEXED                     0xFFFFFFFD
>  #define S_VS_STATE_LS_OUT_PATCH_SIZE(x)                (((unsigned)(x) & 0x1FFF) << 8)
>  #define C_VS_STATE_LS_OUT_PATCH_SIZE           0xFFE000FF
>  #define S_VS_STATE_LS_OUT_VERTEX_SIZE(x)       (((unsigned)(x) & 0xFF) << 24)
>  #define C_VS_STATE_LS_OUT_VERTEX_SIZE          0x00FFFFFF
>
>  /* SI-specific system values. */
>  enum {
>         TGSI_SEMANTIC_DEFAULT_TESSOUTER_SI = TGSI_SEMANTIC_COUNT,
>         TGSI_SEMANTIC_DEFAULT_TESSINNER_SI,
>  };
> diff --git a/src/gallium/drivers/radeonsi/si_state_draw.c b/src/gallium/drivers/radeonsi/si_state_draw.c
> index 0d70ea9..aa528ce 100644
> --- a/src/gallium/drivers/radeonsi/si_state_draw.c
> +++ b/src/gallium/drivers/radeonsi/si_state_draw.c
> @@ -487,22 +487,26 @@ static void si_emit_rasterizer_prim_state(struct si_context *sctx)
>          * reset the stipple pattern at each packet (line strips, line loops).
>          */
>         radeon_set_context_reg(cs, R_028A0C_PA_SC_LINE_STIPPLE,
>                 rs->pa_sc_line_stipple |
>                 S_028A0C_AUTO_RESET_CNTL(rast_prim == PIPE_PRIM_LINES ? 1 : 2));
>
>         sctx->last_rast_prim = rast_prim;
>         sctx->last_sc_line_stipple = rs->pa_sc_line_stipple;
>  }
>
> -static void si_emit_vs_state(struct si_context *sctx)
> +static void si_emit_vs_state(struct si_context *sctx,
> +                            const struct pipe_draw_info *info)
>  {
> +       sctx->current_vs_state &= C_VS_STATE_INDEXED;
> +       sctx->current_vs_state |= S_VS_STATE_INDEXED(!!info->indexed);
> +
>         if (sctx->current_vs_state != sctx->last_vs_state) {
>                 struct radeon_winsys_cs *cs = sctx->b.gfx.cs;
>
>                 radeon_set_sh_reg(cs,
>                         sctx->shader_userdata.sh_base[PIPE_SHADER_VERTEX] +
>                         SI_SGPR_VS_STATE_BITS * 4,
>                         sctx->current_vs_state);
>
>                 sctx->last_vs_state = sctx->current_vs_state;
>         }
> @@ -1298,21 +1302,21 @@ void si_draw_vbo(struct pipe_context *ctx, const struct pipe_draw_info *info)
>                         continue;
>
>                 si_pm4_emit(sctx, state);
>                 sctx->emitted.array[i] = state;
>         }
>         sctx->dirty_states = 0;
>
>         si_emit_rasterizer_prim_state(sctx);
>         if (sctx->tes_shader.cso)
>                 si_emit_derived_tess_state(sctx, info, &num_patches);
> -       si_emit_vs_state(sctx);
> +       si_emit_vs_state(sctx, info);
>         si_emit_draw_registers(sctx, info, num_patches);
>
>         si_ce_pre_draw_synchronization(sctx);
>         si_emit_draw_packets(sctx, info, ib);
>         si_ce_post_draw_synchronization(sctx);
>
>         if (sctx->trace_buf)
>                 si_trace_emit(sctx);
>
>         /* Workaround for a VGT hang when streamout is enabled.
> --
> 2.9.3
>
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