From 2f17099ab9098e4541c7a2564b3dd7af9923c54b Mon Sep 17 00:00:00 2001 From: Imre Deak Date: Thu, 12 Dec 2024 01:03:19 +0200 Subject: [PATCH] drm/connector: Add FIXME for GETRESOURCES ioctl wrt. uninited connectors 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 Reviewed-by: Lyude Paul Reviewed-by: Jani Nikula Acked-by: Alex Deucher Acked-by: Wayne Lin Signed-off-by: Imre Deak Link: https://patchwork.freedesktop.org/patch/msgid/20241211230328.4012496-3-imre.deak@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 37d2e0a4ef4b..8642a2fb25a9 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 && -- 2.25.1