anv/iris: warn gen12 3DSTATE_HS restriction

This should never happen but better off documenting it in case someone
plays with max threads numbers.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3489>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3489>
diff --git a/src/gallium/drivers/iris/iris_state.c b/src/gallium/drivers/iris/iris_state.c
index f361927..5fbb24b 100644
--- a/src/gallium/drivers/iris/iris_state.c
+++ b/src/gallium/drivers/iris/iris_state.c
@@ -4187,6 +4187,16 @@
    iris_pack_command(GENX(3DSTATE_HS), shader->derived_data, hs) {
       INIT_THREAD_DISPATCH_FIELDS(hs, Vertex, MESA_SHADER_TESS_CTRL);
 
+#if GEN_GEN >= 12
+      /* GEN:BUG:1604578095:
+       *
+       *    Hang occurs when the number of max threads is less than 2 times
+       *    the number of instance count. The number of max threads must be
+       *    more than 2 times the number of instance count.
+       */
+      assert((devinfo->max_tcs_threads / 2) > tcs_prog_data->instances);
+#endif
+
       hs.InstanceCount = tcs_prog_data->instances - 1;
       hs.MaximumNumberofThreads = devinfo->max_tcs_threads - 1;
       hs.IncludeVertexHandles = true;
diff --git a/src/intel/vulkan/genX_pipeline.c b/src/intel/vulkan/genX_pipeline.c
index 82be5ab..4dda922 100644
--- a/src/intel/vulkan/genX_pipeline.c
+++ b/src/intel/vulkan/genX_pipeline.c
@@ -1589,6 +1589,17 @@
       /* WA_1606682166 */
       hs.SamplerCount = GEN_GEN == 11 ? 0 : get_sampler_count(tcs_bin);
       hs.BindingTableEntryCount = get_binding_table_entry_count(tcs_bin);
+
+#if GEN_GEN >= 12
+      /* GEN:BUG:1604578095:
+       *
+       *    Hang occurs when the number of max threads is less than 2 times
+       *    the number of instance count. The number of max threads must be
+       *    more than 2 times the number of instance count.
+       */
+      assert((devinfo->max_tcs_threads / 2) > tcs_prog_data->instances);
+#endif
+
       hs.MaximumNumberofThreads = devinfo->max_tcs_threads - 1;
       hs.IncludeVertexHandles = true;
       hs.InstanceCount = tcs_prog_data->instances - 1;