i965: Make get_ccs_surf succeed in alloc_aux

Synchronize the requirements listed in isl_surf_get_ccs_surf with
intel_miptree_supports_ccs by importing a restriction from ISL. Some
implications:
* We successfully create every aux_surf in alloc_aux
* We only return false from alloc_aux if we run out of memory

Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>

2 files changed, 11 insertions, 10 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_blorp.c b/src/mesa/drivers/dri/i965/brw_blorp.c
index 636591c0b79..70c8e0d5816 100644
--- a/src/mesa/drivers/dri/i965/brw_blorp.c
+++ b/src/mesa/drivers/dri/i965/brw_blorp.c
@@ -1209,10 +1209,7 @@ do_single_blorp_clear(struct brw_context *brw, struct gl_framebuffer *fb,
    if (can_fast_clear && !irb->mt->aux_buf) {
       assert(irb->mt->aux_usage == ISL_AUX_USAGE_CCS_D);
       if (!intel_miptree_alloc_aux(brw, irb->mt)) {
-         /* There are a few reasons in addition to out-of-memory, that can
-          * cause intel_miptree_alloc_non_msrt_mcs to fail.  Try to recover by
-          * falling back to non-fast clear.
-          */
+         /* We're out of memory. Fall back to a non-fast clear. */
          can_fast_clear = false;
       }
    }
diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
index 0c7c89a9ac4..0289f4f7e4c 100644
--- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
+++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
@@ -204,6 +204,13 @@ intel_miptree_supports_ccs(struct brw_context *brw,
    if (devinfo->gen < 8 && (mip_mapped || arrayed))
       return false;
 
+   /* The PRM doesn't say this explicitly, but fast-clears don't appear to
+    * work for 3D textures until gen9 where the layout of 3D textures changes
+    * to match 2D array textures.
+    */
+   if (devinfo->gen <= 8 && mt->surf.dim != ISL_SURF_DIM_2D)
+      return false;
+
    /* There's no point in using an MCS buffer if the surface isn't in a
     * renderable format.
     */
@@ -1793,7 +1800,7 @@ intel_miptree_alloc_aux(struct brw_context *brw,
    enum isl_aux_state initial_state;
    uint8_t memset_value;
    struct isl_surf aux_surf;
-   bool aux_surf_ok;
+   MAYBE_UNUSED bool aux_surf_ok;
 
    switch (mt->aux_usage) {
    case ISL_AUX_USAGE_NONE:
@@ -1805,7 +1812,6 @@ intel_miptree_alloc_aux(struct brw_context *brw,
 
       initial_state = ISL_AUX_STATE_AUX_INVALID;
       aux_surf_ok = isl_surf_get_hiz_surf(&brw->isl_dev, &mt->surf, &aux_surf);
-      assert(aux_surf_ok);
       break;
    case ISL_AUX_USAGE_MCS:
       assert(_mesa_is_format_color_format(mt->format));
@@ -1826,7 +1832,6 @@ intel_miptree_alloc_aux(struct brw_context *brw,
       initial_state = ISL_AUX_STATE_CLEAR;
       memset_value = 0xFF;
       aux_surf_ok = isl_surf_get_mcs_surf(&brw->isl_dev, &mt->surf, &aux_surf);
-      assert(aux_surf_ok);
       break;
    case ISL_AUX_USAGE_CCS_D:
    case ISL_AUX_USAGE_CCS_E:
@@ -1852,9 +1857,8 @@ intel_miptree_alloc_aux(struct brw_context *brw,
       break;
    }
 
-   /* Ensure we have a valid aux_surf. */
-   if (aux_surf_ok == false)
-      return false;
+   /* We should have a valid aux_surf. */
+   assert(aux_surf_ok);
 
    /* No work is needed for a zero-sized auxiliary buffer. */
    if (aux_surf.size == 0)