anv: put EXT_mesh_shader behind an environment variable

We are seeing frequent hangs in other workloads when something using
mesh shaders runs at the same time, so gate the feature behind an
environment variable until we figure out what's going on.

v2: (Sagar)
 - Give the mesh enabled variable a more descriptive name

Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Emma Anholt <emma@anholt.net>
Reviewed-by: Sagar Ghuge <sagar.ghuge@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22910>

diff --git a/src/intel/vulkan/anv_device.c b/src/intel/vulkan/anv_device.c
index 6349148..8e3bf18 100644 (file)
--- a/src/intel/vulkan/anv_device.c
+++ b/src/intel/vulkan/anv_device.c
@@ -192,6 +192,12 @@ get_device_extensions(const struct anv_physical_device *device,
       (device->sync_syncobj_type.features & VK_SYNC_FEATURE_CPU_WAIT) != 0;
 
    const bool rt_enabled = ANV_SUPPORT_RT && device->info.has_ray_tracing;
+
+   /* We are seeing hangs on other workloads when something using mesh
+    * shaders runs at the same time, so it's disabled by default.
+    */
+   const bool mesh_shader_enabled = device->info.has_mesh_shading &&
+      debug_get_bool_option("ANV_MESH_SHADER", false);
    const bool nv_mesh_shading_enabled =
       debug_get_bool_option("ANV_EXPERIMENTAL_NV_MESH_SHADER", false);
 
@@ -326,7 +332,7 @@ get_device_extensions(const struct anv_physical_device *device,
       .EXT_memory_budget                     = (!device->info.has_local_mem ||
                                                 device->vram_mappable.available > 0) &&
                                                device->sys.available,
-      .EXT_mesh_shader                       = device->info.has_mesh_shading,
+      .EXT_mesh_shader                       = mesh_shader_enabled,
       .EXT_mutable_descriptor_type           = true,
       .EXT_non_seamless_cube_map             = true,
       .EXT_pci_bus_info                      = true,
@@ -372,7 +378,7 @@ get_device_extensions(const struct anv_physical_device *device,
       .INTEL_shader_integer_functions2       = true,
       .EXT_multi_draw                        = true,
       .NV_compute_shader_derivatives         = true,
-      .NV_mesh_shader                        = device->info.has_mesh_shading &&
+      .NV_mesh_shader                        = mesh_shader_enabled &&
                                                nv_mesh_shading_enabled,
       .VALVE_mutable_descriptor_type         = true,
    };