drm/i915/cmdparser: Make initialisation failure non-fatal

If the developer adds a register in the wrong order, we BUG during boot.
That makes development and testing very difficult. Let's be a bit more
friendly and disable the command parser with a big warning if the tables
are invalid.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160818161718.27187-31-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_cmd_parser.c

@@ -746,17 +746,15 @@ static void fini_hash_table(struct intel_engine_cs *engine)
  * Optionally initializes fields related to batch buffer command parsing in the
  * struct intel_engine_cs based on whether the platform requires software
  * command parsing.
- *
- * Return: non-zero if initialization fails
  */
-int intel_engine_init_cmd_parser(struct intel_engine_cs *engine)
+void intel_engine_init_cmd_parser(struct intel_engine_cs *engine)
 {
 	const struct drm_i915_cmd_table *cmd_tables;
 	int cmd_table_count;
 	int ret;
 
 	if (!IS_GEN7(engine->i915))
-		return 0;
+		return;
 
 	switch (engine->id) {
 	case RCS:
@@ -811,24 +809,27 @@ int intel_engine_init_cmd_parser(struct intel_engine_cs *engine)
 		break;
 	default:
 		MISSING_CASE(engine->id);
-		BUG();
+		return;
 	}
 
-	BUG_ON(!validate_cmds_sorted(engine, cmd_tables, cmd_table_count));
-	BUG_ON(!validate_regs_sorted(engine));
-
-	WARN_ON(!hash_empty(engine->cmd_hash));
+	if (!validate_cmds_sorted(engine, cmd_tables, cmd_table_count)) {
+		DRM_ERROR("%s: command descriptions are not sorted\n",
+			  engine->name);
+		return;
+	}
+	if (!validate_regs_sorted(engine)) {
+		DRM_ERROR("%s: registers are not sorted\n", engine->name);
+		return;
+	}
 
 	ret = init_hash_table(engine, cmd_tables, cmd_table_count);
 	if (ret) {
-		DRM_ERROR("CMD: cmd_parser_init failed!\n");
+		DRM_ERROR("%s: initialised failed!\n", engine->name);
 		fini_hash_table(engine);
-		return ret;
+		return;
 	}
 
 	engine->needs_cmd_parser = true;
-
-	return 0;
 }
 
 /**

drivers/gpu/drm/i915/i915_drv.h

@@ -3541,7 +3541,7 @@ const char *i915_cache_level_str(struct drm_i915_private *i915, int type);
 
 /* i915_cmd_parser.c */
 int i915_cmd_parser_get_version(struct drm_i915_private *dev_priv);
-int intel_engine_init_cmd_parser(struct intel_engine_cs *engine);
+void intel_engine_init_cmd_parser(struct intel_engine_cs *engine);
 void intel_engine_cleanup_cmd_parser(struct intel_engine_cs *engine);
 bool intel_engine_needs_cmd_parser(struct intel_engine_cs *engine);
 int intel_engine_cmd_parser(struct intel_engine_cs *engine,

drivers/gpu/drm/i915/intel_engine_cs.c

@@ -239,6 +239,8 @@ void intel_engine_setup_common(struct intel_engine_cs *engine)
 	intel_engine_init_requests(engine);
 	intel_engine_init_hangcheck(engine);
 	i915_gem_batch_pool_init(engine, &engine->batch_pool);
+
+	intel_engine_init_cmd_parser(engine);
 }
 
 int intel_engine_create_scratch(struct intel_engine_cs *engine, int size)
@@ -301,7 +303,7 @@ int intel_engine_init_common(struct intel_engine_cs *engine)
 	if (ret)
 		return ret;
 
-	return intel_engine_init_cmd_parser(engine);
+	return 0;
 }
 
 /**
@@ -315,7 +317,7 @@ void intel_engine_cleanup_common(struct intel_engine_cs *engine)
 {
 	intel_engine_cleanup_scratch(engine);
 
-	intel_engine_cleanup_cmd_parser(engine);
 	intel_engine_fini_breadcrumbs(engine);
+	intel_engine_cleanup_cmd_parser(engine);
 	i915_gem_batch_pool_fini(&engine->batch_pool);
 }