The kdev->fwnode pointer is never set in drm_sysfs_connector_add(), so dev_fwnode() checks never succeed, making the respective commit NOP. And if drm_sysfs_connector_add() is modified to set kdev->fwnode, it breaks drivers already using components (as it was pointed at [1]), resulting in a deadlock. Lockdep trace is provided below. Granted these two issues, it seems impractical to fix this commit in any sane way. Revert it instead. [1] https://lore.kernel.org/dri-devel/Y24bcYJKGy%2Fgd5fV@phenom.ffwll.local/ ============================================ WARNING: possible recursive locking detected 6.5.0-rc6-next-20230816-10542-g090e2ca9feae-dirty #713 Tainted: G W -------------------------------------------- kworker/u16:0/11 is trying to acquire lock: ffffce0f54bea490 (component_mutex){+.+.}-{3:3}, at: __component_add+0x64/0x170 but task is already holding lock: ffffce0f54bea490 (component_mutex){+.+.}-{3:3}, at: __component_add+0x64/0x170 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(component_mutex); lock(component_mutex); *** DEADLOCK *** May be due to missing lock nesting notation 6 locks held by kworker/u16:0/11: #0: ffff5b7680008d38 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x14c/0x51c #1: ffff8000800abde0 (deferred_probe_work){+.+.}-{0:0}, at: process_one_work+0x14c/0x51c #2: ffff5b76837a2908 (&dev->mutex){....}-{3:3}, at: __device_attach+0x38/0x188 #3: ffffce0f54bea490 (component_mutex){+.+.}-{3:3}, at: __component_add+0x64/0x170 #4: ffffce0f54bdeb40 (drm_connector_list_iter){.+.+}-{0:0}, at: drm_modeset_register_all+0x80/0x9c #5: ffff5b76866ad0d0 (&connector->mutex){+.+.}-{3:3}, at: drm_connector_register.part.0+0x28/0x104 stack backtrace: CPU: 6 PID: 11 Comm: kworker/u16:0 Tainted: G W 6.5.0-rc6-next-20230816-10542-g090e2ca9feae-dirty #713 Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT) Workqueue: events_unbound deferred_probe_work_func Call trace: dump_backtrace+0x98/0xf0 show_stack+0x18/0x24 dump_stack_lvl+0x60/0xac dump_stack+0x18/0x24 print_deadlock_bug+0x254/0x340 __lock_acquire+0x105c/0x1ebc lock_acquire+0x1ec/0x314 __lock_acquire+0x105c/0x1ebc lock_acquire+0x1ec/0x314 __mutex_lock+0xa0/0x77c mutex_lock_nested+0x24/0x30 __component_add+0x64/0x170 component_add+0x14/0x20 drm_sysfs_connector_add+0x144/0x1a0 drm_connector_register.part.0+0x5c/0x104 drm_connector_register_all+0x84/0x160 drm_modeset_register_all+0x80/0x9c drm_dev_register+0x120/0x238 msm_drm_bind+0x550/0x6e0 try_to_bring_up_aggregate_device+0x164/0x1d0 __component_add+0xa8/0x170 component_add+0x14/0x20 dsi_dev_attach+0x20/0x2c dsi_host_attach+0x9c/0x144 devm_mipi_dsi_attach+0x34/0xb4 lt9611uxc_attach_dsi.isra.0+0x84/0xfc lt9611uxc_probe+0x5ac/0x66c i2c_device_probe+0x148/0x290 really_probe+0x148/0x2ac __driver_probe_device+0x78/0x12c driver_probe_device+0x3c/0x160 __device_attach_driver+0xb8/0x138 bus_for_each_drv+0x80/0xdc __device_attach+0x9c/0x188 device_initial_probe+0x14/0x20 bus_probe_device+0xac/0xb0 deferred_probe_work_func+0x8c/0xc8 process_one_work+0x1ec/0x51c worker_thread+0x1ec/0x3e4 kthread+0x120/0x124 ret_from_fork+0x10/0x20 Fixes: c5c51b242062 ("drm/sysfs: Link DRM connectors to corresponding Type-C connectors") Cc: Won Chung <wonchung@xxxxxxxxxx> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> --- drivers/gpu/drm/drm_sysfs.c | 40 ------------------------------------- 1 file changed, 40 deletions(-) diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c index b169b3e44a92..06662cc8d3f4 100644 --- a/drivers/gpu/drm/drm_sysfs.c +++ b/drivers/gpu/drm/drm_sysfs.c @@ -11,14 +11,12 @@ */ #include <linux/acpi.h> -#include <linux/component.h> #include <linux/device.h> #include <linux/err.h> #include <linux/export.h> #include <linux/gfp.h> #include <linux/i2c.h> #include <linux/kdev_t.h> -#include <linux/property.h> #include <linux/slab.h> #include <drm/drm_accel.h> @@ -98,34 +96,6 @@ static char *drm_devnode(const struct device *dev, umode_t *mode) return kasprintf(GFP_KERNEL, "dri/%s", dev_name(dev)); } -static int typec_connector_bind(struct device *dev, - struct device *typec_connector, void *data) -{ - int ret; - - ret = sysfs_create_link(&dev->kobj, &typec_connector->kobj, "typec_connector"); - if (ret) - return ret; - - ret = sysfs_create_link(&typec_connector->kobj, &dev->kobj, "drm_connector"); - if (ret) - sysfs_remove_link(&dev->kobj, "typec_connector"); - - return ret; -} - -static void typec_connector_unbind(struct device *dev, - struct device *typec_connector, void *data) -{ - sysfs_remove_link(&typec_connector->kobj, "drm_connector"); - sysfs_remove_link(&dev->kobj, "typec_connector"); -} - -static const struct component_ops typec_connector_ops = { - .bind = typec_connector_bind, - .unbind = typec_connector_unbind, -}; - static CLASS_ATTR_STRING(version, S_IRUGO, "drm 1.1.0 20060810"); /** @@ -394,16 +364,9 @@ int drm_sysfs_connector_add(struct drm_connector *connector) connector->kdev = kdev; - if (dev_fwnode(kdev)) { - r = component_add(kdev, &typec_connector_ops); - if (r) - 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: @@ -419,9 +382,6 @@ void drm_sysfs_connector_remove(struct drm_connector *connector) if (connector->ddc) sysfs_remove_link(&connector->kdev->kobj, "ddc"); - if (dev_fwnode(connector->kdev)) - component_del(connector->kdev, &typec_connector_ops); - DRM_DEBUG("removing \"%s\" from sysfs\n", connector->name); -- 2.39.2
