+ /*
+ * We could deadlock here in case another thread holding struct_mutex
+ * calls RPM suspend concurrently, since the RPM suspend will wait
+ * first for this RPM suspend to finish. In this case the concurrent
+ * RPM resume will be followed by its RPM suspend counterpart. Still
+ * for consistency return -EAGAIN, which will reschedule this suspend.
+ */
+ if (!mutex_trylock(&dev->struct_mutex)) {
+ DRM_DEBUG_KMS("device lock contention, deffering suspend\n");
+ /*
+ * Bump the expiration timestamp, otherwise the suspend won't
+ * be rescheduled.
+ */
+ pm_runtime_mark_last_busy(device);
+
+ return -EAGAIN;
+ }
+ /*
+ * We are safe here against re-faults, since the fault handler takes
+ * an RPM reference.
+ */
+ i915_gem_release_all_mmaps(dev_priv);
+ mutex_unlock(&dev->struct_mutex);
+