Current code is quite a mess unfortunately, so also add a todo.rst
entry to maybe fix it up eventually.
Cc: Michel Dänzer <michel@xxxxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
---
Documentation/gpu/todo.rst | 12 ++++++++++++
drivers/gpu/drm/drm_connector.c | 10 ++++++++--
drivers/gpu/drm/drm_dp_helper.c | 8 ++++++++
3 files changed, 28 insertions(+), 2 deletions(-)
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index 32787acff0a8..8dc147c93c9c 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -284,6 +284,18 @@ drm_fb_helper tasks
removed: drm_fb_helper_single_add_all_connectors(),
drm_fb_helper_add_one_connector() and drm_fb_helper_remove_one_connector().
+connector register/unregister fixes
+-----------------------------------
+
+- For most connectors it's a no-op to call drm_connector_register/unregister
+ directly from driver code, drm_dev_register/unregister take care of this
+ already. We can remove all of them.
+
+- For dp drivers it's a bit more a mess, since we need the connector to be
+ registered when calling drm_dp_aux_register. Fix this by instead calling
+ drm_dp_aux_init, and moving the actual registering into a late_register
+ callback as recommended in the kerneldoc.
+
Core refactorings
=================
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 4c766624b20d..cd5048ceab1d 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -480,7 +480,10 @@ EXPORT_SYMBOL(drm_connector_cleanup);
* drm_connector_register - register a connector
* @connector: the connector to register
*
- * Register userspace interfaces for a connector
+ * Register userspace interfaces for a connector. Only call this for connectors
+ * which can be hotplugged after drm_dev_register() has been called already,
+ * e.g. DP MST connectors. All other connectors will be registered automatically
+ * when calling drm_dev_register().
*
* Returns:
* Zero on success, error code on failure.
@@ -526,7 +529,10 @@ EXPORT_SYMBOL(drm_connector_register);
* drm_connector_unregister - unregister a connector
* @connector: the connector to unregister
*
- * Unregister userspace interfaces for a connector
+ * Unregister userspace interfaces for a connector. Only call this for
+ * connectors which have registered explicitly by calling drm_dev_register(),
+ * since connectors are unregistered automatically when drm_dev_unregister() is
+ * called.
*/
void drm_connector_unregister(struct drm_connector *connector)
{
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index ffc68d305afe..f373798d82f6 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -1109,6 +1109,14 @@ EXPORT_SYMBOL(drm_dp_aux_init);
* @aux: DisplayPort AUX channel
*
* Automatically calls drm_dp_aux_init() if this hasn't been done yet.
+ * This should only be called when the underlying &struct drm_connector is
+ * initialiazed already. Therefore the best place to call this is from
+ * &drm_connector_funcs.late_register. Not that drivers which don't follow this
+ * will Oops when CONFIG_DRM_DP_AUX_CHARDEV is enabled.
+ *
+ * Drivers which need to use the aux channel before that point (e.g. at driver
+ * load time, before drm_dev_register() has been called) need to call
+ * drm_dp_aux_init().
*
* Returns 0 on success or a negative error code on failure.
*/
--
2.23.0
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