[Mesa-dev] [Mesa-stable] [PATCH] i965: Don't emit SURFACE_STATEs for gather workarounds on Broadwell.

[Chris Forbes]

Did this test run include forcing ARB_gpu_shader5 on?

On Thu, May 29, 2014 at 7:06 PM, Kenneth Graunke <kenneth at whitecape.org> wrote:
> As far as I can tell, Broadwell doesn't need any of the SURFACE_STATE
> workarounds for textureGather() bugs, so there's no need to emit
> a second set of identical copies.
>
> To keep things simple, just point the gather surface index base to the
> same place as the texture surface index base.
>
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> Cc: "10.2" <mesa-stable at lists.freedesktop.org>
> ---
>  src/mesa/drivers/dri/i965/brw_shader.cpp         |  9 +++++++--
>  src/mesa/drivers/dri/i965/brw_wm_surface_state.c | 14 ++++++++------
>  2 files changed, 15 insertions(+), 8 deletions(-)
>
> No Piglit regressions on Broadwell with -t texture.
>
> diff --git a/src/mesa/drivers/dri/i965/brw_shader.cpp b/src/mesa/drivers/dri/i965/brw_shader.cpp
> index f4f1334..7fae416 100644
> --- a/src/mesa/drivers/dri/i965/brw_shader.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_shader.cpp
> @@ -740,8 +740,13 @@ backend_visitor::assign_common_binding_table_offsets(uint32_t next_binding_table
>     }
>
>     if (prog->UsesGather) {
> -      stage_prog_data->binding_table.gather_texture_start = next_binding_table_offset;
> -      next_binding_table_offset += num_textures;
> +      if (brw->gen >= 8) {
> +         stage_prog_data->binding_table.gather_texture_start =
> +            stage_prog_data->binding_table.texture_start;
> +      } else {
> +         stage_prog_data->binding_table.gather_texture_start = next_binding_table_offset;
> +         next_binding_table_offset += num_textures;
> +      }
>     } else {
>        stage_prog_data->binding_table.gather_texture_start = 0xd0d0d0d0;
>     }
> diff --git a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> index c9d9614..3279d3b 100644
> --- a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> +++ b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> @@ -829,12 +829,14 @@ brw_update_texture_surfaces(struct brw_context *brw)
>     /* emit alternate set of surface state for gather. this
>      * allows the surface format to be overriden for only the
>      * gather4 messages. */
> -   if (vs && vs->UsesGather)
> -      update_stage_texture_surfaces(brw, vs, &brw->vs.base, true);
> -   if (gs && gs->UsesGather)
> -      update_stage_texture_surfaces(brw, gs, &brw->gs.base, true);
> -   if (fs && fs->UsesGather)
> -      update_stage_texture_surfaces(brw, fs, &brw->wm.base, true);
> +   if (brw->gen < 8) {
> +      if (vs && vs->UsesGather)
> +         update_stage_texture_surfaces(brw, vs, &brw->vs.base, true);
> +      if (gs && gs->UsesGather)
> +         update_stage_texture_surfaces(brw, gs, &brw->gs.base, true);
> +      if (fs && fs->UsesGather)
> +         update_stage_texture_surfaces(brw, fs, &brw->wm.base, true);
> +   }
>
>     brw->state.dirty.brw |= BRW_NEW_SURFACES;
>  }
> --
> 1.9.1
>
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