[Mesa-dev] [PATCH 10.5/24] st/mesa: don't set sampler states for TBOs

[Ilia Mirkin]

This breaks nouveau (at least on nv50). Same deal as in commit
2b938a390c15a06be8cf706083890c822979508f which fixed a similar issue
where this assumption that buffer doesn't need sampler was also
temporarily introduced.

Do I need to go change a ton of stuff in nouveau, or can we stick with
the original rule where there's a always a sampler associated with a
view?

Generically you're right - no good reason for texelFetch to need a
sampler. Bug I dug around a bunch last time, and I didn't find any
great workarounds. I'll dig around again, but IMO this should be a
candidate for revert.

On Wed, Jun 14, 2017 at 9:08 PM, Marek Olšák <maraeo at gmail.com> wrote:
> From: Marek Olšák <marek.olsak at amd.com>
>
> ---
>
> This prevents a crash later in the series, and it's generally a good
> thing to do.
>
>  src/mesa/state_tracker/st_atom_sampler.c | 11 +++++++++--
>  src/mesa/state_tracker/st_texture.c      |  5 +++--
>  2 files changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/src/mesa/state_tracker/st_atom_sampler.c b/src/mesa/state_tracker/st_atom_sampler.c
> index 21af5ef..7a85a55 100644
> --- a/src/mesa/state_tracker/st_atom_sampler.c
> +++ b/src/mesa/state_tracker/st_atom_sampler.c
> @@ -227,20 +227,21 @@ void
>  st_convert_sampler_from_unit(const struct st_context *st,
>                               struct pipe_sampler_state *sampler,
>                               GLuint texUnit)
>  {
>     const struct gl_texture_object *texobj;
>     struct gl_context *ctx = st->ctx;
>     const struct gl_sampler_object *msamp;
>
>     texobj = ctx->Texture.Unit[texUnit]._Current;
>     assert(texobj);
> +   assert(texobj->Target != GL_TEXTURE_BUFFER);
>
>     msamp = _mesa_get_samplerobj(ctx, texUnit);
>
>     st_convert_sampler(st, texobj, msamp, sampler);
>
>     sampler->lod_bias += ctx->Texture.Unit[texUnit].LodBias;
>     sampler->seamless_cube_map |= ctx->Texture.CubeMapSeamless;
>  }
>
>
> @@ -248,37 +249,43 @@ st_convert_sampler_from_unit(const struct st_context *st,
>   * Update the gallium driver's sampler state for fragment, vertex or
>   * geometry shader stage.
>   */
>  static void
>  update_shader_samplers(struct st_context *st,
>                         enum pipe_shader_type shader_stage,
>                         const struct gl_program *prog,
>                         struct pipe_sampler_state *samplers,
>                         unsigned *out_num_samplers)
>  {
> +   struct gl_context *ctx = st->ctx;
>     GLbitfield samplers_used = prog->SamplersUsed;
>     GLbitfield free_slots = ~prog->SamplersUsed;
>     GLbitfield external_samplers_used = prog->ExternalSamplersUsed;
>     unsigned unit, num_samplers;
>     const struct pipe_sampler_state *states[PIPE_MAX_SAMPLERS];
>
>     if (samplers_used == 0x0)
>        return;
>
>     num_samplers = util_last_bit(samplers_used);
>
>     /* loop over sampler units (aka tex image units) */
>     for (unit = 0; samplers_used; unit++, samplers_used >>= 1) {
>        struct pipe_sampler_state *sampler = samplers + unit;
> +      unsigned tex_unit = prog->SamplerUnits[unit];
>
> -      if (samplers_used & 1) {
> -         st_convert_sampler_from_unit(st, sampler, prog->SamplerUnits[unit]);
> +      /* Don't update the sampler for TBOs. cso_context will not bind sampler
> +       * states that are NULL.
> +       */
> +      if (samplers_used & 1 &&
> +          ctx->Texture.Unit[tex_unit]._Current->Target != GL_TEXTURE_BUFFER) {
> +         st_convert_sampler_from_unit(st, sampler, tex_unit);
>           states[unit] = sampler;
>        } else {
>           states[unit] = NULL;
>        }
>     }
>
>     /* For any external samplers with multiplaner YUV, stuff the additional
>      * sampler states we need at the end.
>      *
>      * Just re-use the existing sampler-state from the primary slot.
> diff --git a/src/mesa/state_tracker/st_texture.c b/src/mesa/state_tracker/st_texture.c
> index 9de3b9a..07c3844 100644
> --- a/src/mesa/state_tracker/st_texture.c
> +++ b/src/mesa/state_tracker/st_texture.c
> @@ -505,26 +505,27 @@ st_destroy_bound_image_handles(struct st_context *st)
>   * Create a texture handle from a texture unit.
>   */
>  static GLuint64
>  st_create_texture_handle_from_unit(struct st_context *st,
>                                     struct gl_program *prog, GLuint texUnit)
>  {
>     struct gl_context *ctx = st->ctx;
>     struct gl_texture_object *texObj;
>     struct pipe_context *pipe = st->pipe;
>     struct pipe_sampler_view *view;
> -   struct pipe_sampler_state sampler;
> +   struct pipe_sampler_state sampler = {0};
>
>     if (!st_update_single_texture(st, &view, texUnit, prog->sh.data->Version))
>        return 0;
>
> -   st_convert_sampler_from_unit(st, &sampler, texUnit);
> +   if (view->target != PIPE_BUFFER)
> +      st_convert_sampler_from_unit(st, &sampler, texUnit);
>
>     texObj = ctx->Texture.Unit[texUnit]._Current;
>     assert(texObj);
>
>     return pipe->create_texture_handle(pipe, view, &sampler);
>  }
>
>
>  /**
>   * Create an image handle from an image unit.
> --
> 2.7.4
>
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