commit 4f5368b5541a902f6596558b05f5c21a9770dd32 Author: Daniel Vetter daniel.vetter@ffwll.ch Date: Fri Jun 14 08:17:23 2019 +0200
drm/kms: Catch mode_object lifetime errors
uncovered a bit a mess in dp drivers. Most drivers (from a quick look, all except i915) register all the dp stuff in their init code, which is too early. With CONFIG_DRM_DP_AUX_CHARDEV this will blow up, because drm_dp_aux_register tries to add a child to a device in sysfs (the connector) which doesn't even exist yet.
No one seems to have cared thus far. But with the above change I also moved the setting of dev->registered after the ->load callback, in an attempt to keep old drivers from hitting any WARN_ON backtraces. But that moved radeon.ko from the "working, by accident" to "now also broken" category.
Since this is a huge mess I figured a revert would be simplest. But this check has already caught issues in i915:
commit 1b9bd09630d4db4827cc04d358a41a16a6bc2cb0 Author: Ville Syrjälä ville.syrjala@linux.intel.com Date: Tue Aug 20 19:16:57 2019 +0300
drm/i915: Do not create a new max_bpc prop for MST connectors
Hence I'd like to retain it. Fix the radeon regression by moving the setting of dev->registered back to were it was, and stop the backtraces with an explicit check for dev->driver->load.
Everyone else will stay as broken with CONFIG_DRM_DP_AUX_CHARDEV. The next patch will improve the kerneldoc and add a todo entry for this.
Fixes: 4f5368b5541a ("drm/kms: Catch mode_object lifetime errors") Cc: Sean Paul sean@poorly.run Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Reported-by: Michel Dänzer michel@daenzer.net Cc: Michel Dänzer michel@daenzer.net Signed-off-by: Daniel Vetter daniel.vetter@intel.com --- drivers/gpu/drm/drm_drv.c | 4 ++-- drivers/gpu/drm/drm_mode_object.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index b634882056c8..0c9978af9f72 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -983,14 +983,14 @@ 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) goto err_minors; }
- dev->registered = true; - if (drm_core_check_feature(dev, DRIVER_MODESET)) drm_modeset_register_all(dev);
diff --git a/drivers/gpu/drm/drm_mode_object.c b/drivers/gpu/drm/drm_mode_object.c index c355ba8e6d5d..6a23e36ed4fe 100644 --- a/drivers/gpu/drm/drm_mode_object.c +++ b/drivers/gpu/drm/drm_mode_object.c @@ -42,7 +42,7 @@ int __drm_mode_object_add(struct drm_device *dev, struct drm_mode_object *obj, { int ret;
- WARN_ON(dev->registered && !obj_free_cb); + WARN_ON(!dev->driver->load && dev->registered && !obj_free_cb);
mutex_lock(&dev->mode_config.idr_mutex); ret = idr_alloc(&dev->mode_config.object_idr, register_obj ? obj : NULL, @@ -104,7 +104,7 @@ void drm_mode_object_register(struct drm_device *dev, void drm_mode_object_unregister(struct drm_device *dev, struct drm_mode_object *object) { - WARN_ON(dev->registered && !object->free_cb); + WARN_ON(!dev->driver->load && dev->registered && !object->free_cb);
mutex_lock(&dev->mode_config.idr_mutex); if (object->id) {