[Intel-gfx] [PATCH] drm/i915: Show per-engine default property values in sysfs

[Chris Wilson]

Why?

/sys/class/drm/card0/engine/rcs0/
├── capabilities
├── class
├── .defaults
│   ├── heartbeat_interval_ms
│   ├── max_busywait_duration_ns
│   ├── preempt_timeout_ms
│   ├── stop_timeout_ms
│   └── timeslice_duration_ms
├── heartbeat_interval_ms
├── instance
├── known_capabilities
├── max_busywait_duration_ns
├── mmio_base
├── name
├── preempt_timeout_ms
├── stop_timeout_ms
└── timeslice_duration_ms

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_engine_cs.c    |  2 +
 drivers/gpu/drm/i915/gt/intel_engine_types.h |  2 +-
 drivers/gpu/drm/i915/gt/sysfs_engines.c      | 94 ++++++++++++++++++++
 3 files changed, 97 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index 4141dacf6ad9..8cdceaccbae4 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -326,6 +326,8 @@ static int intel_engine_setup(struct intel_gt *gt, enum intel_engine_id id)
 	if (INTEL_GEN(i915) == 12 && engine->class == RENDER_CLASS)
 		engine->props.preempt_timeout_ms = 0;
 
+	engine->defaults = engine->props; /* never to change again */
+
 	engine->context_size = intel_engine_context_size(gt, engine->class);
 	if (WARN_ON(engine->context_size > BIT(20)))
 		engine->context_size = 0;
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index 0253ae138e1d..655e1db81847 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -561,7 +561,7 @@ struct intel_engine_cs {
 		unsigned long preempt_timeout_ms;
 		unsigned long stop_timeout_ms;
 		unsigned long timeslice_duration_ms;
-	} props;
+	} props, defaults;
 };
 
 static inline bool
diff --git a/drivers/gpu/drm/i915/gt/sysfs_engines.c b/drivers/gpu/drm/i915/gt/sysfs_engines.c
index 8f9b2f33dbaf..110be61fff02 100644
--- a/drivers/gpu/drm/i915/gt/sysfs_engines.c
+++ b/drivers/gpu/drm/i915/gt/sysfs_engines.c
@@ -191,6 +191,17 @@ max_spin_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 static struct kobj_attribute max_spin_attr =
 __ATTR(max_busywait_duration_ns, 0644, max_spin_show, max_spin_store);
 
+static ssize_t
+max_spin_default(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	struct intel_engine_cs *engine = kobj_to_engine(kobj);
+
+	return sprintf(buf, "%lu\n", engine->defaults.max_busywait_duration_ns);
+}
+
+static struct kobj_attribute max_spin_def =
+__ATTR(max_busywait_duration_ns, 0444, max_spin_default, NULL);
+
 static ssize_t
 timeslice_store(struct kobject *kobj, struct kobj_attribute *attr,
 		const char *buf, size_t count)
@@ -233,6 +244,17 @@ timeslice_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 static struct kobj_attribute timeslice_duration_attr =
 __ATTR(timeslice_duration_ms, 0644, timeslice_show, timeslice_store);
 
+static ssize_t
+timeslice_default(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	struct intel_engine_cs *engine = kobj_to_engine(kobj);
+
+	return sprintf(buf, "%lu\n", engine->defaults.timeslice_duration_ms);
+}
+
+static struct kobj_attribute timeslice_duration_def =
+__ATTR(timeslice_duration_ms, 0444, timeslice_default, NULL);
+
 static ssize_t
 stop_store(struct kobject *kobj, struct kobj_attribute *attr,
 	   const char *buf, size_t count)
@@ -272,6 +294,17 @@ stop_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 static struct kobj_attribute stop_timeout_attr =
 __ATTR(stop_timeout_ms, 0644, stop_show, stop_store);
 
+static ssize_t
+stop_default(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	struct intel_engine_cs *engine = kobj_to_engine(kobj);
+
+	return sprintf(buf, "%lu\n", engine->defaults.stop_timeout_ms);
+}
+
+static struct kobj_attribute stop_timeout_def =
+__ATTR(stop_timeout_ms, 0444, stop_default, NULL);
+
 static ssize_t
 preempt_timeout_store(struct kobject *kobj, struct kobj_attribute *attr,
 		      const char *buf, size_t count)
@@ -316,6 +349,18 @@ preempt_timeout_show(struct kobject *kobj, struct kobj_attribute *attr,
 static struct kobj_attribute preempt_timeout_attr =
 __ATTR(preempt_timeout_ms, 0644, preempt_timeout_show, preempt_timeout_store);
 
+static ssize_t
+preempt_timeout_default(struct kobject *kobj, struct kobj_attribute *attr,
+		     char *buf)
+{
+	struct intel_engine_cs *engine = kobj_to_engine(kobj);
+
+	return sprintf(buf, "%lu\n", engine->defaults.preempt_timeout_ms);
+}
+
+static struct kobj_attribute preempt_timeout_def =
+__ATTR(preempt_timeout_ms, 0444, preempt_timeout_default, NULL);
+
 static ssize_t
 heartbeat_store(struct kobject *kobj, struct kobj_attribute *attr,
 		const char *buf, size_t count)
@@ -359,6 +404,17 @@ heartbeat_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 static struct kobj_attribute heartbeat_interval_attr =
 __ATTR(heartbeat_interval_ms, 0644, heartbeat_show, heartbeat_store);
 
+static ssize_t
+heartbeat_default(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	struct intel_engine_cs *engine = kobj_to_engine(kobj);
+
+	return sprintf(buf, "%lu\n", engine->defaults.heartbeat_interval_ms);
+}
+
+static struct kobj_attribute heartbeat_interval_def =
+__ATTR(heartbeat_interval_ms, 0444, heartbeat_default, NULL);
+
 static void kobj_engine_release(struct kobject *kobj)
 {
 	kfree(kobj);
@@ -390,6 +446,42 @@ kobj_engine(struct kobject *dir, struct intel_engine_cs *engine)
 	return &ke->base;
 }
 
+static void add_defaults(struct kobj_engine *parent)
+{
+	static const struct attribute *files[] = {
+		&max_spin_def.attr,
+		&stop_timeout_def.attr,
+#if CONFIG_DRM_I915_HEARTBEAT_INTERVAL
+		&heartbeat_interval_def.attr,
+#endif
+		NULL
+	};
+	struct kobj_engine *ke;
+
+	ke = kzalloc(sizeof(*ke), GFP_KERNEL);
+	if (!ke)
+		return;
+
+	kobject_init(&ke->base, &kobj_engine_type);
+	ke->engine = parent->engine;
+
+	if (kobject_add(&ke->base, &parent->base, "%s", ".defaults")) {
+		kobject_put(&ke->base);
+		return;
+	}
+
+	if (sysfs_create_files(&ke->base, files))
+		return;
+
+	if (intel_engine_has_timeslices(ke->engine) &&
+	    sysfs_create_file(&ke->base, &timeslice_duration_def.attr))
+		return;
+
+	if (intel_engine_has_preempt_reset(ke->engine) &&
+	    sysfs_create_file(&ke->base, &preempt_timeout_def.attr))
+		return;
+}
+
 void intel_engines_add_sysfs(struct drm_i915_private *i915)
 {
 	static const struct attribute *files[] = {
@@ -433,6 +525,8 @@ void intel_engines_add_sysfs(struct drm_i915_private *i915)
 		    sysfs_create_file(kobj, &preempt_timeout_attr.attr))
 			goto err_engine;
 
+		add_defaults(container_of(kobj, struct kobj_engine, base));
+
 		if (0) {
 err_object:
 			kobject_put(kobj);
-- 
2.20.1