[Mesa-dev] [PATCH 02/36] i965: Keep track of whether LRI is allowed in the context struct.

[Jordan Justen]

On 2015-11-14 13:43:38, Jordan Justen wrote:
> From: Francisco Jerez <currojerez at riseup.net>
> 
> This stores the result of can_do_pipelined_register_writes() in the
> context struct so we can find out later whether LRI can be used to
> program the L3 configuration.
> ---
>  src/mesa/drivers/dri/i965/brw_context.h      | 5 +++++
>  src/mesa/drivers/dri/i965/intel_extensions.c | 8 +++++---
>  2 files changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
> index 4b2db61..20d2dd0 100644
> --- a/src/mesa/drivers/dri/i965/brw_context.h
> +++ b/src/mesa/drivers/dri/i965/brw_context.h
> @@ -840,6 +840,11 @@ struct brw_context
>     bool use_resource_streamer;
>  
>     /**
> +    * Whether LRI can be used to write register values from the batch buffer.
> +    */
> +   bool can_do_pipelined_register_writes;
> +
> +   /**
>      * Some versions of Gen hardware don't do centroid interpolation correctly
>      * on unlit pixels, causing incorrect values for derivatives near triangle
>      * edges.  Enabling this flag causes the fragment shader to use
> diff --git a/src/mesa/drivers/dri/i965/intel_extensions.c b/src/mesa/drivers/dri/i965/intel_extensions.c
> index 386b63c..800e97c 100644
> --- a/src/mesa/drivers/dri/i965/intel_extensions.c
> +++ b/src/mesa/drivers/dri/i965/intel_extensions.c
> @@ -40,8 +40,8 @@
>  static bool
>  can_do_pipelined_register_writes(struct brw_context *brw)
>  {
> -   /* Supposedly, Broadwell just works. */
> -   if (brw->gen >= 8)
> +   /* Supposedly Broadwell just works, and earlier gens are sloppy. */
> +   if (brw->gen != 7)

I think this change should be moved into a separate patch.

Also, what about something like this comment instead?

   /**
    * gen >= 8 specifically allows these writes. gen <= 6 also
    * doesn't block them.
    */

With this split out, the patch is

Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>

>        return true;
>  
>     static int result = -1;
> @@ -319,6 +319,8 @@ intelInitExtensions(struct gl_context *ctx)
>     }
>  
>     brw->predicate.supported = false;
> +   brw->can_do_pipelined_register_writes =
> +      can_do_pipelined_register_writes(brw);
>  
>     if (brw->gen >= 7) {
>        ctx->Extensions.ARB_conservative_depth = true;
> @@ -334,7 +336,7 @@ intelInitExtensions(struct gl_context *ctx)
>        ctx->Extensions.ARB_texture_view = true;
>        ctx->Extensions.ARB_shader_storage_buffer_object = true;
>  
> -      if (can_do_pipelined_register_writes(brw)) {
> +      if (brw->can_do_pipelined_register_writes) {
>           ctx->Extensions.ARB_draw_indirect = true;
>           ctx->Extensions.ARB_transform_feedback2 = true;
>           ctx->Extensions.ARB_transform_feedback3 = true;
> -- 
> 2.6.2
> 
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