From e6e7b48b295afa5a5ab440de0a94d9ad8b3ce2d0 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Thu, 12 Jan 2017 17:15:56 +0100 Subject: [PATCH] drm: Don't race connector registration I was under the misconception that the sysfs dev stuff can be fully set up, and then registered all in one step with device_add. That's true for properties and property groups, but not for parents and child devices. Those must be fully registered before you can register a child. Add a bit of tracking to make sure that asynchronous mst connector hotplugging gets this right. For consistency we rely upon the implicit barriers of the connector->mutex, which is taken anyway, to ensure that at least either the connector or device registration call will work out. Mildly tested since I can't reliably reproduce this on my mst box here. Reported-by: Dave Hansen Cc: Dave Hansen Acked-by: Chris Wilson Cc: Chris Wilson Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/1484237756-2720-1-git-send-email-daniel.vetter@ffwll.ch --- drivers/gpu/drm/drm_connector.c | 3 +++ drivers/gpu/drm/drm_drv.c | 4 ++++ include/drm/drmP.h | 1 + 3 files changed, 8 insertions(+) diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index 8be60a4576b3..7a7019ac9388 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -379,6 +379,9 @@ int drm_connector_register(struct drm_connector *connector) { int ret = 0; + if (!connector->dev->registered) + return 0; + mutex_lock(&connector->mutex); if (connector->registered) goto unlock; diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index a525751b4559..6594b4088f11 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -745,6 +745,8 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags) if (ret) goto err_minors; + dev->registered = true; + if (dev->driver->load) { ret = dev->driver->load(dev, flags); if (ret) @@ -785,6 +787,8 @@ void drm_dev_unregister(struct drm_device *dev) drm_lastclose(dev); + dev->registered = false; + if (drm_core_check_feature(dev, DRIVER_MODESET)) drm_modeset_unregister_all(dev); diff --git a/include/drm/drmP.h b/include/drm/drmP.h index 192016e2b518..9c4ee144b5f6 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -517,6 +517,7 @@ struct drm_device { struct drm_minor *control; /**< Control node */ struct drm_minor *primary; /**< Primary node */ struct drm_minor *render; /**< Render node */ + bool registered; /* currently active master for this device. Protected by master_mutex */ struct drm_master *master;