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

[Jason Ekstrand]

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