[Mesa-dev] [PATCH v2 4/7] intel/isl: Allow multisampling with ISL_FORMAT_HiZ

[Nanley Chery]

On Mon, Sep 12, 2016 at 05:58:21PM -0700, Jason Ekstrand wrote:
> HiZ buffers can be multisampled and, on BDW+, simply using interleaved

As stated in your comment in the second-to-last hunk, this is actually
true for all platforms pre-SKL.

> 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.
> 
> Signed-off-by: Jason Ekstrand <jason at jlekstrand.net>
> Reviewed-by: Chad Versace <chadversary at chromium.org>
> ---
>  src/intel/isl/isl.c        | 4 +++-
>  src/intel/isl/isl_format.c | 9 ++++++++-
>  2 files changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/src/intel/isl/isl.c b/src/intel/isl/isl.c
> index 185984d..33d7079 100644
> --- a/src/intel/isl/isl.c
> +++ b/src/intel/isl/isl.c
> @@ -572,7 +572,6 @@ isl_calc_phys_level0_extent_sa(const struct isl_device *dev,
>           assert(info->depth == 1);
>           assert(info->levels == 1);
>           assert(isl_format_supports_multisampling(dev->info, info->format));
> -         assert(fmtl->bw == 1 && fmtl->bh == 1);
>  
>           *phys_level0_sa = (struct isl_extent4d) {
>              .w = info->width,
> @@ -584,6 +583,9 @@ isl_calc_phys_level0_extent_sa(const struct isl_device *dev,
>           isl_msaa_interleaved_scale_px_to_sa(info->samples,
>                                               &phys_level0_sa->w,
>                                               &phys_level0_sa->h);
> +
> +         phys_level0_sa->w = isl_align(phys_level0_sa->w, fmtl->bw);
> +         phys_level0_sa->h = isl_align(phys_level0_sa->h, fmtl->bh);
>           break;
>        }
>        break;
> diff --git a/src/intel/isl/isl_format.c b/src/intel/isl/isl_format.c
> index f3429be..02df1ce 100644
> --- a/src/intel/isl/isl_format.c
> +++ b/src/intel/isl/isl_format.c
> @@ -444,10 +444,17 @@ isl_format_supports_multisampling(const struct brw_device_info *devinfo,
>      *       - any compressed texture format (BC*)
>      *       - any YCRCB* format
>      *
> -    * The restriction on the format's size is removed on Broadwell.
> +    * The restriction on the format's size is removed on Broadwell.  Also,
> +    * there is an exception for HiZ which we treat as a compressed format and
> +    * is allowed to be multisampled on Broadwell and earlier.
>      */
>     if (devinfo->gen < 8 && isl_format_get_layout(format)->bpb > 64) {
>        return false;
> +   } else if (format == ISL_FORMAT_HIZ) {

Because HiZ's bpb > 64, this if case should be moved up to handle the
pre-BDW platforms. 

> +      /* 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;
>     } else if (isl_format_is_compressed(format)) {
>        return false;
>     } else if (isl_format_is_yuv(format)) {
> -- 
> 2.5.0.400.gff86faf
> 
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