[Mesa-dev] [PATCH 3/6] intel/isl: Allow multisampling with ISL_FORMAT_HiZ

[Chad Versace]

On Fri 02 Sep 2016, Jason Ekstrand wrote:
> HiZ buffers can be multisampled and, on BDW+, simply using interleaved
> multisampling with a compression block size of 8x4 samples yields the
> correct HiZ surface size calculations.  Unfortunately, choose_msaa_layout
> was rejecting multisampled HiZ buffers because of format checks.  Now that
> we have a simple helper for determining if a format supports multisampling,
> that's an easy enough issue to fix.
> ---
>  src/intel/isl/isl_format.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/src/intel/isl/isl_format.c b/src/intel/isl/isl_format.c
> index 5d43fe7..02df1ce 100644
> --- a/src/intel/isl/isl_format.c
> +++ b/src/intel/isl/isl_format.c
> @@ -450,6 +450,11 @@ isl_format_supports_multisampling(const struct brw_device_info *devinfo,
>      */
>     if (devinfo->gen < 8 && isl_format_get_layout(format)->bpb > 64) {
>        return false;
> +   } else if (format == ISL_FORMAT_HIZ) {
> +      /* On SKL+, HiZ is always single-sampled even when the primary surface
> +       * is multisampled.  See also isl_surf_get_hiz_surf().
> +       */
> +      return devinfo->gen <= 8;

There's an element of surprising elegance in this patch.

For patches 1-3,
Reviewed-by: Chad Versace <chadversary at chromium.org>