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drm/i915: Take all modeset locks for DP MST hotplug 

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.

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
This commit is contained in:
Daniel Vetter 2015-07-09 23:44:31 +02:00
parent 4676ba0be7
commit 8bb4da1df5
1 changed files with 6 additions and 6 deletions
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12
drivers/gpu/drm/i915/intel_dp_mst.c
View File

@ -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);