[Mesa-dev] [PATCH 12/27] i965: Assign hw-binding table index for each UBO constant buffer.

[Pohjolainen, Topi]

On Tue, Apr 28, 2015 at 11:08:09PM +0300, Abdiel Janulgue wrote:
> To be able to refer to a constant buffer, the resource streamer needs
> to index it with a hardware binding table entry. This blankets the ubo
> buffers with hardware binding table indices.
> 
> Gather constants hardware fetches in 16-entry binding table blocks.
> So we need to use a block that is unused.
> 
> Signed-off-by: Abdiel Janulgue <abdiel.janulgue at linux.intel.com>
> ---
>  src/mesa/drivers/dri/i965/brw_context.h          | 11 +++++++++++
>  src/mesa/drivers/dri/i965/brw_wm_surface_state.c |  6 ++++++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
> index e25c64d..276c359 100644
> --- a/src/mesa/drivers/dri/i965/brw_context.h
> +++ b/src/mesa/drivers/dri/i965/brw_context.h
> @@ -678,6 +678,17 @@ struct brw_vs_prog_data {
>  
>  #define SURF_INDEX_GEN6_SOL_BINDING(t) (t)
>  
> +/** Start of hardware binding table index for uniform gather constant entries.
> + *  This must be aligned to the start of a hardware binding table block (a block
> + *  is a group 16 binding table entries).
> + */
> +#define BRW_UNIFORM_GATHER_INDEX_START 32
> +
> +/** Appended to the end of the binding table index for uniform constant buffers to indicate

Wrap this line.

> + *  start of the UBO gather constant binding table.
> + */
> +#define BRW_UBO_GATHER_INDEX_APPEND 2
> +
>  /* Note: brw_gs_prog_data_compare() must be updated when adding fields to
>   * this struct!
>   */
> 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 161d140..ce61554 100644
> --- a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> +++ b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> @@ -884,6 +884,7 @@ brw_upload_ubo_surfaces(struct brw_context *brw,
>  
>     uint32_t *surf_offsets =
>        &stage_state->surf_offset[prog_data->binding_table.ubo_start];
> +   bool use_gather = (brw->gather_pool.bo != NULL);

I would move this closer to the only use. This won't get re-used in the
rest of the series.

>  
>     for (int i = 0; i < shader->NumUniformBlocks; i++) {
>        struct gl_uniform_buffer_binding *binding;
> @@ -904,6 +905,11 @@ brw_upload_ubo_surfaces(struct brw_context *brw,
>                                    bo->size - binding->Offset,
>                                    &surf_offsets[i],
>                                    dword_pitch);
> +      if (use_gather) {

Or simply:

         if (brw->gather_pool.bo) {

> +         int bt_idx = BRW_UNIFORM_GATHER_INDEX_START + BRW_UBO_GATHER_INDEX_APPEND + i;

Wrap this line.

> +         gen7_update_binding_table(brw, stage_state->stage,
> +                                   bt_idx, surf_offsets[i]);
> +      }
>     }
>  
>     if (shader->NumUniformBlocks)
> -- 
> 1.9.1
> 
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