drm_kms_helper_poll_disable(dev);
 
        /* turn off display hw */
+       drm_modeset_lock_all(dev);
        list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
                drm_helper_connector_dpms(connector, DRM_MODE_DPMS_OFF);
        }
+       drm_modeset_unlock_all(dev);
 
        /* unpin the front buffers */
        list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
        if (fbcon) {
                drm_helper_resume_force_mode(dev);
                /* turn on display hw */
+               drm_modeset_lock_all(dev);
                list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
                        drm_helper_connector_dpms(connector, DRM_MODE_DPMS_ON);
                }
+               drm_modeset_unlock_all(dev);
        }
 
        drm_kms_helper_poll_enable(dev);