From: Ville Syrjälä <ville.syrjala@linux.intel.com> maillist inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IC0U9U CVE: NA Reference: https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commi... ---------------------------------------------------------------------- Currently drm_sysfs_connector_add() attempts to register the "ddc" symlink (based one connector->ddc) before the driver's .early_register() hook has been called. That is too early for i915 which only fully registers the aux ch and associated i2c bus from said hook (to prevent half initialized stuff getting exposed to userspace). This causes my attempt at using drm_connector_init_with_ddc() to fail, and the entire connector disappears from sysfs on account of sysfs_create_link() failing. To fix that split the sysfs symlink stuff into separate functions (drm_sysfs_connector_add_late() and drm_sysfs_connector_remove_early()) which are called on the opposite side of the .later_register() and .early_unregister() hooks. Cc: Andrzej Pietrasiewicz <andrzej.p@collabora.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Andrzej Hajda <a.hajda@samsung.com> Cc: Emil Velikov <emil.velikov@collabora.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20230829113920.13713-3-ville.s... Reviewed-by: Jani Nikula <jani.nikula@intel.com> Acked-by: Thomas Zimmermann <tzimmermann@suse.de> #irc --- drivers/gpu/drm/drm_connector.c | 9 +++++++++ drivers/gpu/drm/drm_internal.h | 2 ++ drivers/gpu/drm/drm_sysfs.c | 22 +++++++++++++++------- 3 files changed, 26 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index 309aad5f0..e7b9dd963 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -631,6 +631,10 @@ int drm_connector_register(struct drm_connector *connector) goto err_debugfs; } + ret = drm_sysfs_connector_add_late(connector); + if (ret) + goto err_late_register; + drm_mode_object_register(connector->dev, &connector->base); connector->registration_state = DRM_CONNECTOR_REGISTERED; @@ -647,6 +651,9 @@ int drm_connector_register(struct drm_connector *connector) mutex_unlock(&connector_list_lock); goto unlock; +err_late_register: + if (connector->funcs->early_unregister) + connector->funcs->early_unregister(connector); err_debugfs: drm_debugfs_connector_remove(connector); drm_sysfs_connector_remove(connector); @@ -681,6 +688,8 @@ void drm_connector_unregister(struct drm_connector *connector) connector->privacy_screen, &connector->privacy_screen_notifier); + drm_sysfs_connector_remove_early(connector); + if (connector->funcs->early_unregister) connector->funcs->early_unregister(connector); diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h index 0ef5fc2a6..beaa00960 100644 --- a/drivers/gpu/drm/drm_internal.h +++ b/drivers/gpu/drm/drm_internal.h @@ -149,6 +149,8 @@ int drm_sysfs_init(void); void drm_sysfs_destroy(void); struct device *drm_sysfs_minor_alloc(struct drm_minor *minor); int drm_sysfs_connector_add(struct drm_connector *connector); +int drm_sysfs_connector_add_late(struct drm_connector *connector); +void drm_sysfs_connector_remove_early(struct drm_connector *connector); void drm_sysfs_connector_remove(struct drm_connector *connector); void drm_sysfs_lease_event(struct drm_device *dev); diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c index b169b3e44..a953f69a3 100644 --- a/drivers/gpu/drm/drm_sysfs.c +++ b/drivers/gpu/drm/drm_sysfs.c @@ -400,10 +400,6 @@ int drm_sysfs_connector_add(struct drm_connector *connector) drm_err(dev, "failed to add component to create link to typec connector\n"); } - if (connector->ddc) - return sysfs_create_link(&connector->kdev->kobj, - &connector->ddc->dev.kobj, "ddc"); - return 0; err_free: @@ -411,13 +407,25 @@ int drm_sysfs_connector_add(struct drm_connector *connector) return r; } -void drm_sysfs_connector_remove(struct drm_connector *connector) +int drm_sysfs_connector_add_late(struct drm_connector *connector) { - if (!connector->kdev) - return; + if (connector->ddc) + return sysfs_create_link(&connector->kdev->kobj, + &connector->ddc->dev.kobj, "ddc"); + + return 0; +} +void drm_sysfs_connector_remove_early(struct drm_connector *connector) +{ if (connector->ddc) sysfs_remove_link(&connector->kdev->kobj, "ddc"); +} + +void drm_sysfs_connector_remove(struct drm_connector *connector) +{ + if (!connector->kdev) + return; if (dev_fwnode(connector->kdev)) component_del(connector->kdev, &typec_connector_ops); -- 2.33.0