drm/fb-helper: Push down modeset lock into FB helpers

Move the modeset locking from drivers into FB helpers.

v2: Also handle intel_connector_add_to_fbdev.

v3: Prevent race in intel_dp_mst with ->detect (Maarten)

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thierry Reding <treding@nvidia.com> (v1)
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170704151833.17304-2-daniel.vetter@ffwll.ch

1 files changed, 3 insertions, 6 deletions

diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index 2cf046beae0f..9aa959284497 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -501,11 +501,8 @@ static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topolo
 static void intel_dp_register_mst_connector(struct drm_connector *connector)
 {
         struct intel_connector *intel_connector = to_intel_connector(connector);
-        struct drm_device *dev = connector->dev;
 
-        drm_modeset_lock_all(dev);
         intel_connector_add_to_fbdev(intel_connector);
-        drm_modeset_unlock_all(dev);
 
         drm_connector_register(&intel_connector->base);
 }
@@ -514,15 +511,15 @@ static void intel_dp_destroy_mst_connector(struct drm_dp_mst_topology_mgr *mgr,
                                            struct drm_connector *connector)
 {
         struct intel_connector *intel_connector = to_intel_connector(connector);
-        struct drm_device *dev = connector->dev;
 
         drm_connector_unregister(connector);
 
         /* need to nuke the connector */
-        drm_modeset_lock_all(dev);
         intel_connector_remove_from_fbdev(intel_connector);
+        /* prevent race with the check in ->detect */
+        drm_modeset_lock(&connector->dev->mode_config.connection_mutex, NULL);
         intel_connector->mst_port = NULL;
-        drm_modeset_unlock_all(dev);
+        drm_modeset_unlock(&connector->dev->mode_config.connection_mutex);
 
         drm_connector_unreference(&intel_connector->base);
         DRM_DEBUG_KMS("\n");