[Mesa-dev] [v2 05/19] i965: Add helper for detecting lossless compression

[Ben Widawsky]

On Thu, Feb 11, 2016 at 08:33:58PM +0200, Topi Pohjolainen wrote:
> Signed-off-by: Topi Pohjolainen <topi.pohjolainen at intel.com>
> ---
>  src/mesa/drivers/dri/i965/intel_mipmap_tree.c | 26 ++++++++++++++++++++++++++
>  src/mesa/drivers/dri/i965/intel_mipmap_tree.h |  4 ++++
>  2 files changed, 30 insertions(+)
> 
> diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> index 5f739d9..31de1ff 100644
> --- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> +++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> @@ -266,6 +266,32 @@ intel_miptree_supports_non_msrt_fast_clear(struct brw_context *brw,
>        return true;
>  }
>  
> +/* On Gen9 support for color buffer compression was extended to single
> + * sampled surfaces. This is a helper considering both auxiliary buffer
> + * type and number of samples telling if the given miptree represents
> + * the new single sampled case - also called lossless compression.
> + */
> +bool
> +intel_miptree_is_lossless_compressed(const struct brw_context *brw,
> +                                     const struct intel_mipmap_tree *mt)
> +{
> +   /* Only available from Gen9 onwards. */
> +   if (brw->gen < 9)
> +      return false;
> +
> +   /* Compression always requires auxiliary buffer. */
> +   if (!mt->mcs_mt)
> +      return false;
> +
> +   /* Single sample compression is represented re-using msaa compression
> +    * layout type: "Compressed Multisampled Surfaces".
> +    */
> +   if (mt->msaa_layout != INTEL_MSAA_LAYOUT_CMS)
> +      return false;
> +
> +   /* And finally distinguish between msaa and single sample case. */
> +   return mt->num_samples <= 1;
> +}
>  
>  /**
>   * Determine depth format corresponding to a depth+stencil format,
> diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.h b/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
> index 64f73ea..13d4d7e 100644
> --- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
> +++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
> @@ -667,6 +667,10 @@ intel_get_non_msrt_mcs_alignment(struct intel_mipmap_tree *mt,
>                                   unsigned *width_px, unsigned *height);
>  
>  bool
> +intel_miptree_is_lossless_compressed(const struct brw_context *brw,
> +                                     const struct intel_mipmap_tree *mt);
> +
> +bool
>  intel_miptree_alloc_non_msrt_mcs(struct brw_context *brw,
>                                   struct intel_mipmap_tree *mt);
>  

So I take it this was one of the big changes from my feedback earlier. Do you
prefer this result, or what? I can live with the old thing if you want it.