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drm/connector: Add FIXME for GETRESOURCES ioctl wrt. uninited connectors

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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 requires a bigger change, for now adding a FIXME: comment for
it.

v2: Remove references to the patchset from the commit log. (Jani)

Suggested-by: Simona Vetter <simona.vetter@ffwll.ch>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241211230328.4012496-3-imre.deak@intel.com
This commit is contained in:
Imre Deak 2024-12-12 01:03:19 +02:00
parent 1d985ddabb
commit 2f17099ab9
1 changed files with 9 additions and 0 deletions
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9
drivers/gpu/drm/drm_mode_config.c
View file

@ -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 &&