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.vet...@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);
--
2.1.4
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