iris: Avoid sampling some MCS surfaces with clear

Supposedly avoids GPU hangs in BF4. See HSD 1707282275 and 14013111325.

v2. Fix bug in WA implementation. (Sagar)

Cc: mesa-stable
Reviewed-by: Sagar Ghuge <sagar.ghuge@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8755>

src/gallium/drivers/iris/iris_blit.c

@@ -571,6 +571,13 @@ get_copy_region_aux_settings(struct iris_context *ice,
       break;
    case ISL_AUX_USAGE_MCS:
    case ISL_AUX_USAGE_MCS_CCS:
+      if (!is_render_target &&
+          !iris_can_sample_mcs_with_clear(devinfo, res)) {
+         *out_aux_usage = res->aux.usage;
+         *out_clear_supported = false;
+         break;
+      }
+      FALLTHROUGH;
    case ISL_AUX_USAGE_CCS_E:
    case ISL_AUX_USAGE_GFX12_CCS_E:
       *out_aux_usage = res->aux.usage;

src/gallium/drivers/iris/iris_resolve.c

@@ -885,6 +885,24 @@ iris_image_view_aux_usage(struct iris_context *ice,
    return ISL_AUX_USAGE_NONE;
 }
 
+bool
+iris_can_sample_mcs_with_clear(const struct intel_device_info *devinfo,
+                               const struct iris_resource *res)
+{
+   assert(isl_aux_usage_has_mcs(res->aux.usage));
+
+   /* On TGL, the sampler has an issue with some 8 and 16bpp MSAA fast clears.
+    * See HSD 1707282275, wa_14013111325. Due to the use of
+    * format-reinterpretation, a simplified workaround is implemented.
+    */
+   if (devinfo->ver >= 12 &&
+       isl_format_get_layout(res->surf.format)->bpb <= 16) {
+      return false;
+   }
+
+   return true;
+}
+
 static bool
 isl_formats_are_fast_clear_compatible(enum isl_format a, enum isl_format b)
 {
@@ -909,6 +927,9 @@ iris_resource_prepare_texture(struct iris_context *ice,
                               uint32_t start_level, uint32_t num_levels,
                               uint32_t start_layer, uint32_t num_layers)
 {
+   const struct iris_screen *screen = (void *) ice->ctx.screen;
+   const struct intel_device_info *devinfo = &screen->devinfo;
+
    enum isl_aux_usage aux_usage =
       iris_resource_texture_aux_usage(ice, res, view_format);
 
@@ -921,6 +942,11 @@ iris_resource_prepare_texture(struct iris_context *ice,
    if (!isl_formats_are_fast_clear_compatible(res->surf.format, view_format))
       clear_supported = false;
 
+   if (isl_aux_usage_has_mcs(aux_usage) &&
+       !iris_can_sample_mcs_with_clear(devinfo, res)) {
+      clear_supported = false;
+   }
+
    iris_resource_prepare_access(ice, res, start_level, num_levels,
                                 start_layer, num_layers,
                                 aux_usage, clear_supported);

src/gallium/drivers/iris/iris_resource.h

@@ -531,6 +531,9 @@ bool iris_resource_level_has_hiz(const struct iris_resource *res,
 bool iris_sample_with_depth_aux(const struct intel_device_info *devinfo,
                                 const struct iris_resource *res);
 
+bool iris_can_sample_mcs_with_clear(const struct intel_device_info *devinfo,
+                                    const struct iris_resource *res);
+
 bool iris_has_color_unresolved(const struct iris_resource *res,
                                unsigned start_level, unsigned num_levels,
                                unsigned start_layer, unsigned num_layers);