drm/i915: Compute the global scheduler caps

Do a pass over all the engines upon starting to determine the global
scheduler capability flags (those that are agreed upon by all).
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190226102404.29153-7-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem.c

@@ -4698,6 +4698,8 @@ static int __i915_gem_restart_engines(void *data)
 		}
 	}
 
+	intel_engines_set_scheduler_caps(i915);
+
 	return 0;
 }
 

drivers/gpu/drm/i915/intel_engine_cs.c

@@ -608,6 +608,45 @@ int intel_engine_setup_common(struct intel_engine_cs *engine)
 	return err;
 }
 
+void intel_engines_set_scheduler_caps(struct drm_i915_private *i915)
+{
+	static const struct {
+		u8 engine;
+		u8 sched;
+	} map[] = {
+#define MAP(x, y) { ilog2(I915_ENGINE_HAS_##x), ilog2(I915_SCHEDULER_CAP_##y) }
+		MAP(PREEMPTION, PREEMPTION),
+#undef MAP
+	};
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	u32 enabled, disabled;
+
+	enabled = 0;
+	disabled = 0;
+	for_each_engine(engine, i915, id) { /* all engines must agree! */
+		int i;
+
+		if (engine->schedule)
+			enabled |= (I915_SCHEDULER_CAP_ENABLED |
+				    I915_SCHEDULER_CAP_PRIORITY);
+		else
+			disabled |= (I915_SCHEDULER_CAP_ENABLED |
+				     I915_SCHEDULER_CAP_PRIORITY);
+
+		for (i = 0; i < ARRAY_SIZE(map); i++) {
+			if (engine->flags & BIT(map[i].engine))
+				enabled |= BIT(map[i].sched);
+			else
+				disabled |= BIT(map[i].sched);
+		}
+	}
+
+	i915->caps.scheduler = enabled & ~disabled;
+	if (!(i915->caps.scheduler & I915_SCHEDULER_CAP_ENABLED))
+		i915->caps.scheduler = 0;
+}
+
 static void __intel_context_unpin(struct i915_gem_context *ctx,
 				  struct intel_engine_cs *engine)
 {

drivers/gpu/drm/i915/intel_lrc.c

@@ -2292,12 +2292,6 @@ void intel_execlists_set_default_submission(struct intel_engine_cs *engine)
 	engine->flags |= I915_ENGINE_SUPPORTS_STATS;
 	if (engine->i915->preempt_context)
 		engine->flags |= I915_ENGINE_HAS_PREEMPTION;
-
-	engine->i915->caps.scheduler =
-		I915_SCHEDULER_CAP_ENABLED |
-		I915_SCHEDULER_CAP_PRIORITY;
-	if (intel_engine_has_preemption(engine))
-		engine->i915->caps.scheduler |= I915_SCHEDULER_CAP_PREEMPTION;
 }
 
 static void

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -593,6 +593,8 @@ intel_engine_has_preemption(const struct intel_engine_cs *engine)
 	return engine->flags & I915_ENGINE_HAS_PREEMPTION;
 }
 
+void intel_engines_set_scheduler_caps(struct drm_i915_private *i915);
+
 static inline bool __execlists_need_preempt(int prio, int last)
 {
 	/*