drm: Handle properties in the core for atomic drivers

The reason behind the original indirection through the helper
functions was to allow existing drivers to overwrite how they handle
properties. For example when a vendor-specific userspace had
expectations that didn't match atomic. That seemed likely, since
atomic is standardizing a _lot_ more of the behaviour of a kms driver.

But 20 drivers later there's no such need at all. Worse, this forces
all drivers to hook up the default behaviour, breaking userspace if
they forget to do that. And it forces us to export a bunch of core
function just for those helpers.

And finally, these helpers are the last places using
drm_atomic_legacy_backoff() and the implicit acquire_ctx.

This patch here just implements the new behaviour and updates the
docs. Follow-up patches will garbage-collect all the dead code.

v2: Fixup docs even better!

v3: Make it actually work ...

v4: Drop the uses_atomic_modeset() checks from the previous patch
again, since they're now moved up in the callchain.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Archit Taneja <architt@codeaurora.org> (v3)
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170725120204.2107-1-daniel.vetter@ffwll.ch

drivers/gpu/drm/drm_atomic.c

@@ -1864,9 +1864,60 @@ static struct drm_pending_vblank_event *create_vblank_event(
 	return e;
 }
 
-static int atomic_set_prop(struct drm_atomic_state *state,
-		struct drm_mode_object *obj, struct drm_property *prop,
-		uint64_t prop_value)
+int drm_atomic_connector_commit_dpms(struct drm_atomic_state *state,
+				     struct drm_connector *connector,
+				     int mode)
+{
+	struct drm_connector *tmp_connector;
+	struct drm_connector_state *new_conn_state;
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *crtc_state;
+	int i, ret, old_mode = connector->dpms;
+	bool active = false;
+
+	ret = drm_modeset_lock(&state->dev->mode_config.connection_mutex,
+			       state->acquire_ctx);
+	if (ret)
+		return ret;
+
+	if (mode != DRM_MODE_DPMS_ON)
+		mode = DRM_MODE_DPMS_OFF;
+	connector->dpms = mode;
+
+	crtc = connector->state->crtc;
+	if (!crtc)
+		goto out;
+	ret = drm_atomic_add_affected_connectors(state, crtc);
+	if (ret)
+		goto out;
+
+	crtc_state = drm_atomic_get_crtc_state(state, crtc);
+	if (IS_ERR(crtc_state)) {
+		ret = PTR_ERR(crtc_state);
+		goto out;
+	}
+
+	for_each_new_connector_in_state(state, tmp_connector, new_conn_state, i) {
+		if (new_conn_state->crtc != crtc)
+			continue;
+		if (tmp_connector->dpms == DRM_MODE_DPMS_ON) {
+			active = true;
+			break;
+		}
+	}
+
+	crtc_state->active = active;
+	ret = drm_atomic_commit(state);
+out:
+	if (ret != 0)
+		connector->dpms = old_mode;
+	return ret;
+}
+
+int drm_atomic_set_property(struct drm_atomic_state *state,
+			    struct drm_mode_object *obj,
+			    struct drm_property *prop,
+			    uint64_t prop_value)
 {
 	struct drm_mode_object *ref;
 	int ret;
@@ -2286,7 +2337,8 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 				goto out;
 			}
 
-			ret = atomic_set_prop(state, obj, prop, prop_value);
+			ret = drm_atomic_set_property(state, obj, prop,
+						      prop_value);
 			if (ret) {
 				drm_mode_object_put(obj);
 				goto out;

drivers/gpu/drm/drm_connector.c

@@ -717,9 +717,9 @@ DRM_ENUM_NAME_FN(drm_get_tv_subconnector_name,
  * 	drivers, it remaps to controlling the "ACTIVE" property on the CRTC the
  * 	connector is linked to. Drivers should never set this property directly,
  * 	it is handled by the DRM core by calling the &drm_connector_funcs.dpms
- * 	callback. Atomic drivers should implement this hook using
- * 	drm_atomic_helper_connector_dpms(). This is the only property standard
- * 	connector property that userspace can change.
+ * 	callback. For atomic drivers the remapping to the "ACTIVE" property is
+ * 	implemented in the DRM core.  This is the only standard connector
+ * 	property that userspace can change.
  * PATH:
  * 	Connector path property to identify how this sink is physically
  * 	connected. Used by DP MST. This should be set by calling
@@ -1225,7 +1225,7 @@ int drm_mode_connector_set_obj_prop(struct drm_mode_object *obj,
 	} else if (connector->funcs->set_property)
 		ret = connector->funcs->set_property(connector, property, value);
 
-	if (!ret && !drm_drv_uses_atomic_modeset(property->dev))
+	if (!ret)
 		drm_object_property_set_value(&connector->base, property, value);
 	return ret;
 }

drivers/gpu/drm/drm_crtc.c

@@ -736,7 +736,7 @@ int drm_mode_crtc_set_obj_prop(struct drm_mode_object *obj,
 
 	if (crtc->funcs->set_property)
 		ret = crtc->funcs->set_property(crtc, property, value);
-	if (!ret && !drm_drv_uses_atomic_modeset(property->dev))
+	if (!ret)
 		drm_object_property_set_value(obj, property, value);
 
 	return ret;

drivers/gpu/drm/drm_crtc_helper.c

@@ -863,8 +863,7 @@ static int drm_helper_choose_crtc_dpms(struct drm_crtc *crtc)
  * provided by the driver.
  *
  * This function is deprecated.  New drivers must implement atomic modeset
- * support, for which this function is unsuitable. Instead drivers should use
- * drm_atomic_helper_connector_dpms().
+ * support, where DPMS is handled in the DRM core.
  *
  * Returns:
  * Always returns 0.

drivers/gpu/drm/drm_crtc_internal.h

@@ -178,6 +178,13 @@ struct drm_minor;
 int drm_atomic_debugfs_init(struct drm_minor *minor);
 #endif
 
+int drm_atomic_connector_commit_dpms(struct drm_atomic_state *state,
+				     struct drm_connector *connector,
+				     int mode);
+int drm_atomic_set_property(struct drm_atomic_state *state,
+			    struct drm_mode_object *obj,
+			    struct drm_property *prop,
+			    uint64_t prop_value);
 int drm_atomic_get_property(struct drm_mode_object *obj,
 			    struct drm_property *property, uint64_t *val);
 int drm_mode_atomic_ioctl(struct drm_device *dev,

drivers/gpu/drm/drm_mode_object.c

@@ -392,6 +392,83 @@ struct drm_property *drm_mode_obj_find_prop_id(struct drm_mode_object *obj,
 	return NULL;
 }
 
+static int set_property_legacy(struct drm_mode_object *obj,
+			       struct drm_property *prop,
+			       uint64_t prop_value)
+{
+	struct drm_device *dev = prop->dev;
+	struct drm_mode_object *ref;
+	int ret = -EINVAL;
+
+	if (!drm_property_change_valid_get(prop, prop_value, &ref))
+		return -EINVAL;
+
+	drm_modeset_lock_all(dev);
+	switch (obj->type) {
+	case DRM_MODE_OBJECT_CONNECTOR:
+		ret = drm_mode_connector_set_obj_prop(obj, prop,
+						      prop_value);
+		break;
+	case DRM_MODE_OBJECT_CRTC:
+		ret = drm_mode_crtc_set_obj_prop(obj, prop, prop_value);
+		break;
+	case DRM_MODE_OBJECT_PLANE:
+		ret = drm_mode_plane_set_obj_prop(obj_to_plane(obj),
+						  prop, prop_value);
+		break;
+	}
+	drm_property_change_valid_put(prop, ref);
+	drm_modeset_unlock_all(dev);
+
+	return ret;
+}
+
+static int set_property_atomic(struct drm_mode_object *obj,
+			       struct drm_property *prop,
+			       uint64_t prop_value)
+{
+	struct drm_device *dev = prop->dev;
+	struct drm_atomic_state *state;
+	struct drm_modeset_acquire_ctx ctx;
+	int ret;
+
+	drm_modeset_acquire_init(&ctx, 0);
+
+	state = drm_atomic_state_alloc(dev);
+	if (!state)
+		return -ENOMEM;
+	state->acquire_ctx = &ctx;
+retry:
+	if (prop == state->dev->mode_config.dpms_property) {
+		if (obj->type != DRM_MODE_OBJECT_CONNECTOR) {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		ret = drm_atomic_connector_commit_dpms(state,
+						       obj_to_connector(obj),
+						       prop_value);
+	} else {
+		ret = drm_atomic_set_property(state, obj, prop, prop_value);
+		if (ret)
+			goto out;
+		ret = drm_atomic_commit(state);
+	}
+out:
+	if (ret == -EDEADLK) {
+		drm_atomic_state_clear(state);
+		drm_modeset_backoff(&ctx);
+		goto retry;
+	}
+
+	drm_atomic_state_put(state);
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
+
+	return ret;
+}
+
 int drm_mode_obj_set_property_ioctl(struct drm_device *dev, void *data,
 				    struct drm_file *file_priv)
 {
@@ -399,18 +476,13 @@ int drm_mode_obj_set_property_ioctl(struct drm_device *dev, void *data,
 	struct drm_mode_object *arg_obj;
 	struct drm_property *property;
 	int ret = -EINVAL;
-	struct drm_mode_object *ref;
 
 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
 		return -EINVAL;
 
-	drm_modeset_lock_all(dev);
-
 	arg_obj = drm_mode_object_find(dev, arg->obj_id, arg->obj_type);
-	if (!arg_obj) {
-		ret = -ENOENT;
-		goto out;
-	}
+	if (!arg_obj)
+		return -ENOENT;
 
 	if (!arg_obj->properties)
 		goto out_unref;
@@ -419,28 +491,12 @@ int drm_mode_obj_set_property_ioctl(struct drm_device *dev, void *data,
 	if (!property)
 		goto out_unref;
 
-	if (!drm_property_change_valid_get(property, arg->value, &ref))
-		goto out_unref;
-
-	switch (arg_obj->type) {
-	case DRM_MODE_OBJECT_CONNECTOR:
-		ret = drm_mode_connector_set_obj_prop(arg_obj, property,
-						      arg->value);
-		break;
-	case DRM_MODE_OBJECT_CRTC:
-		ret = drm_mode_crtc_set_obj_prop(arg_obj, property, arg->value);
-		break;
-	case DRM_MODE_OBJECT_PLANE:
-		ret = drm_mode_plane_set_obj_prop(obj_to_plane(arg_obj),
-						  property, arg->value);
-		break;
-	}
-
-	drm_property_change_valid_put(property, ref);
+	if (drm_drv_uses_atomic_modeset(property->dev))
+		ret = set_property_atomic(arg_obj, property, arg->value);
+	else
+		ret = set_property_legacy(arg_obj, property, arg->value);
 
 out_unref:
 	drm_mode_object_put(arg_obj);
-out:
-	drm_modeset_unlock_all(dev);
 	return ret;
 }

drivers/gpu/drm/drm_plane.c

@@ -448,7 +448,7 @@ int drm_mode_plane_set_obj_prop(struct drm_plane *plane,
 
 	if (plane->funcs->set_property)
 		ret = plane->funcs->set_property(plane, property, value);
-	if (!ret && !drm_drv_uses_atomic_modeset(property->dev))
+	if (!ret)
 		drm_object_property_set_value(obj, property, value);
 
 	return ret;

include/drm/drm_connector.h

@@ -382,8 +382,8 @@ struct drm_connector_funcs {
 	 * implement the 4 level DPMS support on the connector any more, but
 	 * instead only have an on/off "ACTIVE" property on the CRTC object.
 	 *
-	 * Drivers implementing atomic modeset should use
-	 * drm_atomic_helper_connector_dpms() to implement this hook.
+	 * This hook is not used by atomic drivers, remapping of the legacy DPMS
+	 * property is entirely handled in the DRM core.
 	 *
 	 * RETURNS:
 	 *
@@ -480,11 +480,9 @@ struct drm_connector_funcs {
 	 * This is the legacy entry point to update a property attached to the
 	 * connector.
 	 *
-	 * Drivers implementing atomic modeset should use
-	 * drm_atomic_helper_connector_set_property() to implement this hook.
-	 *
 	 * This callback is optional if the driver does not support any legacy
-	 * driver-private properties.
+	 * driver-private properties. For atomic drivers it is not used because
+	 * property handling is done entirely in the DRM core.
 	 *
 	 * RETURNS:
 	 *

include/drm/drm_crtc.h

@@ -473,11 +473,9 @@ struct drm_crtc_funcs {
 	 * This is the legacy entry point to update a property attached to the
 	 * CRTC.
 	 *
-	 * Drivers implementing atomic modeset should use
-	 * drm_atomic_helper_crtc_set_property() to implement this hook.
-	 *
 	 * This callback is optional if the driver does not support any legacy
-	 * driver-private properties.
+	 * driver-private properties. For atomic drivers it is not used because
+	 * property handling is done entirely in the DRM core.
 	 *
 	 * RETURNS:
 	 *

include/drm/drm_plane.h

@@ -233,11 +233,9 @@ struct drm_plane_funcs {
 	 * This is the legacy entry point to update a property attached to the
 	 * plane.
 	 *
-	 * Drivers implementing atomic modeset should use
-	 * drm_atomic_helper_plane_set_property() to implement this hook.
-	 *
 	 * This callback is optional if the driver does not support any legacy
-	 * driver-private properties.
+	 * driver-private properties. For atomic drivers it is not used because
+	 * property handling is done entirely in the DRM core.
 	 *
 	 * RETURNS:
 	 *