While auditing various users of the connector/encoder lists I realized that the atomic code is a very prolific user of them. And it only ever grabs the mode_config->connection_mutex, but not the mode_config->mutex like all the other code walking encoder/connector lists.
The problem is that we can't grab the mode_config.mutex late in atomic code since that would lead to locking inversions. And we don't want to grab it unconditionally like the legacy set_config modeset path since that would render all the fine-grained locking moot.
Instead just grab more locks in the dp mst hotplug code. Note that drm_connector_init (which is the one adding the connector to these lists) already uses drm_modeset_lock_all.
The other reason for grabbing all locks is that the dpms off in the unplug function amounts to a modeset, so better to take all required locks for that.
Signed-off-by: Daniel Vetter daniel.vetter@intel.com --- drivers/gpu/drm/i915/intel_dp_mst.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c index 6e4cc5334f47..d0b2569c6241 100644 --- a/drivers/gpu/drm/i915/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/intel_dp_mst.c @@ -442,9 +442,9 @@ static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topolo
drm_mode_connector_set_path_property(connector, pathprop); drm_reinit_primary_mode_group(dev); - mutex_lock(&dev->mode_config.mutex); + drm_modeset_lock_all(dev); intel_connector_add_to_fbdev(intel_connector); - mutex_unlock(&dev->mode_config.mutex); + drm_modeset_unlock_all(dev); drm_connector_register(&intel_connector->base); return connector; } @@ -455,16 +455,16 @@ static void intel_dp_destroy_mst_connector(struct drm_dp_mst_topology_mgr *mgr, struct intel_connector *intel_connector = to_intel_connector(connector); struct drm_device *dev = connector->dev; /* need to nuke the connector */ - mutex_lock(&dev->mode_config.mutex); + drm_modeset_lock_all(dev); intel_connector_dpms(connector, DRM_MODE_DPMS_OFF); - mutex_unlock(&dev->mode_config.mutex); + drm_modeset_unlock_all(dev);
intel_connector->unregister(intel_connector);
- mutex_lock(&dev->mode_config.mutex); + drm_modeset_lock_all(dev); intel_connector_remove_from_fbdev(intel_connector); drm_connector_cleanup(connector); - mutex_unlock(&dev->mode_config.mutex); + drm_modeset_unlock_all(dev);
drm_reinit_primary_mode_group(dev);