diff mbox series

[v2,1/4] drm/dp: Add a way to init/add a connector in separate steps

Message ID 20241126161859.1858058-2-imre.deak@intel.com (mailing list archive)
State New
Headers show
Series drm/dp: Expose only a properly inited connector | expand

Commit Message

Imre Deak Nov. 26, 2024, 4:18 p.m. UTC 
Atm when the connector is added to the drm_mode_config::connector_list,
the connector may not be fully initialized yet. This is not a problem
for user space, which will see the connector only after it's registered
later, it could be a problem for in-kernel users looking up connectors
via the above list.

To resolve the above issue, add a way to separately initialize the DRM
core specific parts of the connector and add it to the above list. This
will move adding the connector to the list after the properties on the
connector have been added, this is ok since these steps don't have a
dependency.

v2: (Jani)
- Let initing DDC as well via drm_connector_init_core().
- Rename __drm_connector_init to drm_connector_init_core_and_add().

Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> (v1)
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/gpu/drm/drm_connector.c | 111 ++++++++++++++++++++++++++------
 include/drm/drm_connector.h     |   6 ++
 2 files changed, 97 insertions(+), 20 deletions(-)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index fc35f47e2849e..fd7acae8656b2 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -218,11 +218,11 @@  void drm_connector_free_work_fn(struct work_struct *work)
 	}
 }
 
-static int __drm_connector_init(struct drm_device *dev,
-				struct drm_connector *connector,
-				const struct drm_connector_funcs *funcs,
-				int connector_type,
-				struct i2c_adapter *ddc)
+static int __drm_connector_init_core(struct drm_device *dev,
+				     struct drm_connector *connector,
+				     const struct drm_connector_funcs *funcs,
+				     int connector_type,
+				     struct i2c_adapter *ddc)
 {
 	struct drm_mode_config *config = &dev->mode_config;
 	int ret;
@@ -273,6 +273,7 @@  static int __drm_connector_init(struct drm_device *dev,
 	/* provide ddc symlink in sysfs */
 	connector->ddc = ddc;
 
+	INIT_LIST_HEAD(&connector->head);
 	INIT_LIST_HEAD(&connector->global_connector_list_entry);
 	INIT_LIST_HEAD(&connector->probed_modes);
 	INIT_LIST_HEAD(&connector->modes);
@@ -288,14 +289,6 @@  static int __drm_connector_init(struct drm_device *dev,
 
 	drm_connector_get_cmdline_mode(connector);
 
-	/* We should add connectors at the end to avoid upsetting the connector
-	 * index too much.
-	 */
-	spin_lock_irq(&config->connector_list_lock);
-	list_add_tail(&connector->head, &config->connector_list);
-	config->num_connector++;
-	spin_unlock_irq(&config->connector_list_lock);
-
 	if (connector_type != DRM_MODE_CONNECTOR_VIRTUAL &&
 	    connector_type != DRM_MODE_CONNECTOR_WRITEBACK)
 		drm_connector_attach_edid_property(connector);
@@ -332,6 +325,86 @@  static int __drm_connector_init(struct drm_device *dev,
 	return ret;
 }
 
+/**
+ * drm_connector_init_core - Initialize the core state of a preallocated connector
+ * @dev: DRM device
+ * @connector: the connector to init
+ * @funcs: callbacks for this connector
+ * @connector_type: user visible type of the connector
+ * @ddc: pointer to the associated ddc adapter
+ *
+ * Initialises the core state of preallocated connector. This is
+ * equivalent to drm_connector_init(), without adding the connector to
+ * drm_mode_config::connector_list. This call must be followed by calling
+ * drm_connector_add() during initialization to expose the connector to
+ * in-kernel users via the above list.
+ *
+ * Returns:
+ * Zero on success, error code on failure.
+ */
+int drm_connector_init_core(struct drm_device *dev,
+			    struct drm_connector *connector,
+			    const struct drm_connector_funcs *funcs,
+			    int connector_type,
+			    struct i2c_adapter *ddc)
+{
+	if (drm_WARN_ON(dev, !(funcs && funcs->destroy)))
+		return -EINVAL;
+
+	return __drm_connector_init_core(dev, connector, funcs, connector_type, ddc);
+}
+EXPORT_SYMBOL(drm_connector_init_core);
+
+/**
+ * drm_connector_add - Add the connector
+ * @connector: the connector to add
+ *
+ * Add the connector to the drm_mode_config::connector_list, exposing the
+ * connector to in-kernel users. This call must be preceded by a call to
+ * drm_connector_init_core().
+ */
+void drm_connector_add(struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+	struct drm_mode_config *config = &dev->mode_config;
+
+	spin_lock_irq(&config->connector_list_lock);
+	list_add_tail(&connector->head, &config->connector_list);
+	config->num_connector++;
+	spin_unlock_irq(&config->connector_list_lock);
+}
+EXPORT_SYMBOL(drm_connector_add);
+
+static void drm_connector_remove(struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+
+	if (list_empty(&connector->head))
+		return;
+
+	spin_lock_irq(&dev->mode_config.connector_list_lock);
+	list_del_init(&connector->head);
+	dev->mode_config.num_connector--;
+	spin_unlock_irq(&dev->mode_config.connector_list_lock);
+}
+
+static int drm_connector_init_core_and_add(struct drm_device *dev,
+					   struct drm_connector *connector,
+					   const struct drm_connector_funcs *funcs,
+					   int connector_type,
+					   struct i2c_adapter *ddc)
+{
+	int ret;
+
+	ret = __drm_connector_init_core(dev, connector, funcs, connector_type, ddc);
+	if (ret)
+		return ret;
+
+	drm_connector_add(connector);
+
+	return 0;
+}
+
 /**
  * drm_connector_init - Init a preallocated connector
  * @dev: DRM device
@@ -361,7 +434,7 @@  int drm_connector_init(struct drm_device *dev,
 	if (drm_WARN_ON(dev, !(funcs && funcs->destroy)))
 		return -EINVAL;
 
-	return __drm_connector_init(dev, connector, funcs, connector_type, NULL);
+	return drm_connector_init_core_and_add(dev, connector, funcs, connector_type, NULL);
 }
 EXPORT_SYMBOL(drm_connector_init);
 
@@ -398,7 +471,7 @@  int drm_connector_init_with_ddc(struct drm_device *dev,
 	if (drm_WARN_ON(dev, !(funcs && funcs->destroy)))
 		return -EINVAL;
 
-	return __drm_connector_init(dev, connector, funcs, connector_type, ddc);
+	return drm_connector_init_core_and_add(dev, connector, funcs, connector_type, ddc);
 }
 EXPORT_SYMBOL(drm_connector_init_with_ddc);
 
@@ -442,7 +515,7 @@  int drmm_connector_init(struct drm_device *dev,
 	if (drm_WARN_ON(dev, funcs && funcs->destroy))
 		return -EINVAL;
 
-	ret = __drm_connector_init(dev, connector, funcs, connector_type, ddc);
+	ret = drm_connector_init_core_and_add(dev, connector, funcs, connector_type, ddc);
 	if (ret)
 		return ret;
 
@@ -659,10 +732,8 @@  void drm_connector_cleanup(struct drm_connector *connector)
 	connector->name = NULL;
 	fwnode_handle_put(connector->fwnode);
 	connector->fwnode = NULL;
-	spin_lock_irq(&dev->mode_config.connector_list_lock);
-	list_del(&connector->head);
-	dev->mode_config.num_connector--;
-	spin_unlock_irq(&dev->mode_config.connector_list_lock);
+
+	drm_connector_remove(connector);
 
 	WARN_ON(connector->state && !connector->funcs->atomic_destroy_state);
 	if (connector->state && connector->funcs->atomic_destroy_state)
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index e3fa43291f449..2476dcbd3c34d 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -2122,6 +2122,12 @@  struct drm_connector {
 
 #define obj_to_connector(x) container_of(x, struct drm_connector, base)
 
+int drm_connector_init_core(struct drm_device *dev,
+			    struct drm_connector *connector,
+			    const struct drm_connector_funcs *funcs,
+			    int connector_type,
+			    struct i2c_adapter *ddc);
+void drm_connector_add(struct drm_connector *connector);
 int drm_connector_init(struct drm_device *dev,
 		       struct drm_connector *connector,
 		       const struct drm_connector_funcs *funcs,