[PATCH 4.4 192/342] drm/nouveau/kms: take mode_config mutex in connector hotplug path

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ben Skeggs <bskeggs@xxxxxxxxxx>

commit 0a882cadbc63fd2da3994af7115b4ada2fcbd638 upstream.

fdo#93634

Signed-off-by: Ben Skeggs <bskeggs@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/gpu/drm/nouveau/nouveau_connector.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -969,10 +969,13 @@ nouveau_connector_hotplug(struct nvif_no
 
 		NV_DEBUG(drm, "%splugged %s\n", plugged ? "" : "un", name);
 
+		mutex_lock(&drm->dev->mode_config.mutex);
 		if (plugged)
 			drm_helper_connector_dpms(connector, DRM_MODE_DPMS_ON);
 		else
 			drm_helper_connector_dpms(connector, DRM_MODE_DPMS_OFF);
+		mutex_unlock(&drm->dev->mode_config.mutex);
+
 		drm_helper_hpd_irq_event(connector->dev);
 	}