[PATCH v3 02/11] drm/connector: Add FIXME for GETRESOURCES ioctl wrt. uninited connectors

[Imre Deak]

The connectors enumerated by the GETRESOURCES ioctl may not be fully
initialized yet wrt. to the state set up during connector registration
(for instance the connector's debugfs/sysfs interfaces may not exist
yet). This can happen in two ways:

1. Connectors initialized and added to the
   drm_mode_config::connector_list during driver loading will be visible
   to the GETRESOURCES ioctl caller once the driver is registered via
   drm_dev_register()->drm_minor_register(DRM_MINOR_PRIMARY) and before
   the connectors are registered via drm_dev_register()->
   drm_modeset_register_all().

2. Dynamic connectors (MST) - after being initialized - may be added to
   the connector_list after the driver is loaded and registered and before
   the connector's userspace interfaces (debugfs, sysfs etc.) are added
   in drm_connector_dynamic_register().

A solution for 1. would be to register the driver only after the
connectors are registered, for 2. to add the connector to connector_list
only after the userspace interfaces are registered.

The fix would require a bigger change, not the topic of this patchset,
so adding only a FIXME comment here.

Suggested-by: Simona Vetter <simona.vetter at ffwll.ch>
Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 drivers/gpu/drm/drm_mode_config.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
index 37d2e0a4ef4be..8642a2fb25a90 100644
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -150,6 +150,15 @@ int drm_mode_getresources(struct drm_device *dev, void *data,
 	drm_connector_list_iter_begin(dev, &conn_iter);
 	count = 0;
 	connector_id = u64_to_user_ptr(card_res->connector_id_ptr);
+	/*
+	 * FIXME: the connectors on the list may not be fully initialized yet,
+	 * if the ioctl is called before the connectors are registered. (See
+	 * drm_dev_register()->drm_modeset_register_all() for static and
+	 * drm_connector_dynamic_register() for dynamic connectors.)
+	 * The driver should only get registered after static connectors are
+	 * fully initialized and dynamic connectors should be added to the
+	 * connector list only after fully initializing them.
+	 */
 	drm_for_each_connector_iter(connector, &conn_iter) {
 		/* only expose writeback connectors if userspace understands them */
 		if (!file_priv->writeback_connectors &&
-- 
2.44.2