iris: Use ISL_AUX_USAGE_HIZ_CCS_WT to indicate write-through HiZ

Previously, we always set the aux_usage to ISL_AUX_USAGE_HIZ_CCS and let
ISL choose write-through based on isl_surf_supports_hiz_ccs_wt.  This
commit makes us choose explicitly at surface creation time whether to
use HIZ_CCS or HIZ_CCS_WT based on the same set of conditions.  This is
more explicit and should be more robust as it lets us choose WT mode in
one place rather than trusting isl_surf_supports_hiz_ccs_wt to return
the same thing every time.

Reviewed-by: Nanley Chery <[email protected]>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4056>

3 files changed, 22 insertions, 10 deletions

diff --git a/src/gallium/drivers/iris/iris_blit.c b/src/gallium/drivers/iris/iris_blit.c
index 8dca0c4a362..43382f91954 100644
--- a/src/gallium/drivers/iris/iris_blit.c
+++ b/src/gallium/drivers/iris/iris_blit.c
@@ -577,6 +577,7 @@ get_copy_region_aux_settings(struct iris_context *ice,
    switch (res->aux.usage) {
    case ISL_AUX_USAGE_HIZ:
    case ISL_AUX_USAGE_HIZ_CCS:
+   case ISL_AUX_USAGE_HIZ_CCS_WT:
       if (is_render_target) {
          *out_aux_usage = res->aux.usage;
       } else {
diff --git a/src/gallium/drivers/iris/iris_resolve.c b/src/gallium/drivers/iris/iris_resolve.c
index cfd7d53eb38..fdb45a37c71 100644
--- a/src/gallium/drivers/iris/iris_resolve.c
+++ b/src/gallium/drivers/iris/iris_resolve.c
@@ -569,10 +569,9 @@ iris_sample_with_depth_aux(const struct gen_device_info *devinfo,
          break;
       return false;
    case ISL_AUX_USAGE_HIZ_CCS:
-      /* Write through mode must have been enabled for prior writes. */
-      if (isl_surf_supports_hiz_ccs_wt(devinfo, &res->surf, res->aux.usage))
-         break;
       return false;
+   case ISL_AUX_USAGE_HIZ_CCS_WT:
+      break;
    default:
       return false;
    }
@@ -953,8 +952,12 @@ iris_resource_texture_aux_usage(struct iris_context *ice,
       break;
 
    case ISL_AUX_USAGE_HIZ_CCS:
+      assert(!iris_sample_with_depth_aux(devinfo, res));
+      return ISL_AUX_USAGE_NONE;
+
+   case ISL_AUX_USAGE_HIZ_CCS_WT:
       if (iris_sample_with_depth_aux(devinfo, res))
-         return ISL_AUX_USAGE_CCS_E;
+         return ISL_AUX_USAGE_HIZ_CCS_WT;
       break;
 
    case ISL_AUX_USAGE_MCS:
diff --git a/src/gallium/drivers/iris/iris_resource.c b/src/gallium/drivers/iris/iris_resource.c
index 7ca6097840a..8142c42f3dc 100644
--- a/src/gallium/drivers/iris/iris_resource.c
+++ b/src/gallium/drivers/iris/iris_resource.c
@@ -480,8 +480,18 @@ iris_resource_configure_aux(struct iris_screen *screen,
       res->aux.possible_usages |=
          1 << (has_ccs ? ISL_AUX_USAGE_MCS_CCS : ISL_AUX_USAGE_MCS);
    } else if (has_hiz) {
-      res->aux.possible_usages |=
-         1 << (has_ccs ? ISL_AUX_USAGE_HIZ_CCS : ISL_AUX_USAGE_HIZ);
+      if (!has_ccs) {
+         res->aux.possible_usages |= 1 << ISL_AUX_USAGE_HIZ;
+      } else if (res->surf.samples == 1 &&
+                 (res->surf.usage & ISL_SURF_USAGE_TEXTURE_BIT)) {
+         /* If this resource is single-sampled and will be used as a texture,
+          * put the HiZ surface in write-through mode so that we can sample
+          * from it.
+          */
+         res->aux.possible_usages |= 1 << ISL_AUX_USAGE_HIZ_CCS_WT;
+      } else {
+         res->aux.possible_usages |= 1 << ISL_AUX_USAGE_HIZ_CCS;
+      }
    } else if (has_ccs) {
       if (want_ccs_e_for_format(devinfo, res->surf.format))
          res->aux.possible_usages |= 1 << ISL_AUX_USAGE_CCS_E;
@@ -500,11 +510,8 @@ iris_resource_configure_aux(struct iris_screen *screen,
    if (!devinfo->has_sample_with_hiz || res->surf.samples > 1)
       res->aux.sampler_usages &= ~(1 << ISL_AUX_USAGE_HIZ);
 
-   /* We don't always support sampling with HIZ_CCS. But when we do, treat it
-    * as CCS_E.*/
+   /* ISL_AUX_USAGE_HIZ_CCS doesn't support sampling at all */
    res->aux.sampler_usages &= ~(1 << ISL_AUX_USAGE_HIZ_CCS);
-   if (isl_surf_supports_hiz_ccs_wt(devinfo, &res->surf, res->aux.usage))
-      res->aux.sampler_usages |= 1 << ISL_AUX_USAGE_CCS_E;
 
    enum isl_aux_state initial_state;
    *aux_size_B = 0;
@@ -517,6 +524,7 @@ iris_resource_configure_aux(struct iris_screen *screen,
       return !res->mod_info || res->mod_info->aux_usage == ISL_AUX_USAGE_NONE;
    case ISL_AUX_USAGE_HIZ:
    case ISL_AUX_USAGE_HIZ_CCS:
+   case ISL_AUX_USAGE_HIZ_CCS_WT:
       initial_state = ISL_AUX_STATE_AUX_INVALID;
       break;
    case ISL_AUX_USAGE_MCS: