[Mesa-dev] [PATCH v2 4/7] 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.

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) {
+      /* 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