/* We may be recursing from the signal callback of another i915 fence */
        spin_lock_nested(&request->lock, SINGLE_DEPTH_NESTING);
+
        GEM_BUG_ON(test_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags));
        set_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags);
+
        if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags) &&
            !i915_request_enable_breadcrumb(request))
                intel_engine_queue_breadcrumbs(engine);
+
        spin_unlock(&request->lock);
 
        engine->emit_fini_breadcrumb(request,
 
        /* We may be recursing from the signal callback of another i915 fence */
        spin_lock_nested(&request->lock, SINGLE_DEPTH_NESTING);
+
+       /*
+        * As we do not allow WAIT to preempt inflight requests,
+        * once we have executed a request, along with triggering
+        * any execution callbacks, we must preserve its ordering
+        * within the non-preemptible FIFO.
+        */
+       BUILD_BUG_ON(__NO_PREEMPTION & ~I915_PRIORITY_MASK); /* only internal */
+       request->sched.attr.priority |= __NO_PREEMPTION;
+
        if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags))
                i915_request_cancel_breadcrumb(request);
+
        GEM_BUG_ON(!test_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags));
        clear_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags);
+
        spin_unlock(&request->lock);
 
        /* Transfer back from the global per-engine timeline to per-context */
 
        goto err_client_b;
 }
 
+static int __i915_sw_fence_call
+dummy_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)
+{
+       return NOTIFY_DONE;
+}
+
+static struct i915_request *dummy_request(struct intel_engine_cs *engine)
+{
+       struct i915_request *rq;
+
+       rq = kzalloc(sizeof(*rq), GFP_KERNEL);
+       if (!rq)
+               return NULL;
+
+       INIT_LIST_HEAD(&rq->active_list);
+       rq->engine = engine;
+
+       i915_sched_node_init(&rq->sched);
+
+       /* mark this request as permanently incomplete */
+       rq->fence.seqno = 1;
+       BUILD_BUG_ON(sizeof(rq->fence.seqno) != 8); /* upper 32b == 0 */
+       rq->hwsp_seqno = (u32 *)&rq->fence.seqno + 1;
+       GEM_BUG_ON(i915_request_completed(rq));
+
+       i915_sw_fence_init(&rq->submit, dummy_notify);
+       i915_sw_fence_commit(&rq->submit);
+
+       return rq;
+}
+
+static void dummy_request_free(struct i915_request *dummy)
+{
+       i915_request_mark_complete(dummy);
+       i915_sched_node_fini(&dummy->sched);
+       i915_sw_fence_fini(&dummy->submit);
+
+       dma_fence_free(&dummy->fence);
+}
+
+static int live_suppress_wait_preempt(void *arg)
+{
+       struct drm_i915_private *i915 = arg;
+       struct preempt_client client[4];
+       struct intel_engine_cs *engine;
+       enum intel_engine_id id;
+       intel_wakeref_t wakeref;
+       int err = -ENOMEM;
+       int i;
+
+       /*
+        * Waiters are given a little priority nudge, but not enough
+        * to actually cause any preemption. Double check that we do
+        * not needlessly generate preempt-to-idle cycles.
+        */
+
+       if (!HAS_LOGICAL_RING_PREEMPTION(i915))
+               return 0;
+
+       mutex_lock(&i915->drm.struct_mutex);
+       wakeref = intel_runtime_pm_get(i915);
+
+       if (preempt_client_init(i915, &client[0])) /* ELSP[0] */
+               goto err_unlock;
+       if (preempt_client_init(i915, &client[1])) /* ELSP[1] */
+               goto err_client_0;
+       if (preempt_client_init(i915, &client[2])) /* head of queue */
+               goto err_client_1;
+       if (preempt_client_init(i915, &client[3])) /* bystander */
+               goto err_client_2;
+
+       for_each_engine(engine, i915, id) {
+               int depth;
+
+               if (!engine->emit_init_breadcrumb)
+                       continue;
+
+               for (depth = 0; depth < ARRAY_SIZE(client); depth++) {
+                       struct i915_request *rq[ARRAY_SIZE(client)];
+                       struct i915_request *dummy;
+
+                       engine->execlists.preempt_hang.count = 0;
+
+                       dummy = dummy_request(engine);
+                       if (!dummy)
+                               goto err_client_3;
+
+                       for (i = 0; i < ARRAY_SIZE(client); i++) {
+                               rq[i] = igt_spinner_create_request(&client[i].spin,
+                                                                  client[i].ctx, engine,
+                                                                  MI_NOOP);
+                               if (IS_ERR(rq[i])) {
+                                       err = PTR_ERR(rq[i]);
+                                       goto err_wedged;
+                               }
+
+                               /* Disable NEWCLIENT promotion */
+                               __i915_active_request_set(&rq[i]->timeline->last_request,
+                                                         dummy);
+                               i915_request_add(rq[i]);
+                       }
+
+                       dummy_request_free(dummy);
+
+                       GEM_BUG_ON(i915_request_completed(rq[0]));
+                       if (!igt_wait_for_spinner(&client[0].spin, rq[0])) {
+                               pr_err("%s: First client failed to start\n",
+                                      engine->name);
+                               goto err_wedged;
+                       }
+                       GEM_BUG_ON(!i915_request_started(rq[0]));
+
+                       if (i915_request_wait(rq[depth],
+                                             I915_WAIT_LOCKED |
+                                             I915_WAIT_PRIORITY,
+                                             1) != -ETIME) {
+                               pr_err("%s: Waiter depth:%d completed!\n",
+                                      engine->name, depth);
+                               goto err_wedged;
+                       }
+
+                       for (i = 0; i < ARRAY_SIZE(client); i++)
+                               igt_spinner_end(&client[i].spin);
+
+                       if (igt_flush_test(i915, I915_WAIT_LOCKED))
+                               goto err_wedged;
+
+                       if (engine->execlists.preempt_hang.count) {
+                               pr_err("%s: Preemption recorded x%d, depth %d; should have been suppressed!\n",
+                                      engine->name,
+                                      engine->execlists.preempt_hang.count,
+                                      depth);
+                               err = -EINVAL;
+                               goto err_client_3;
+                       }
+               }
+       }
+
+       err = 0;
+err_client_3:
+       preempt_client_fini(&client[3]);
+err_client_2:
+       preempt_client_fini(&client[2]);
+err_client_1:
+       preempt_client_fini(&client[1]);
+err_client_0:
+       preempt_client_fini(&client[0]);
+err_unlock:
+       if (igt_flush_test(i915, I915_WAIT_LOCKED))
+               err = -EIO;
+       intel_runtime_pm_put(i915, wakeref);
+       mutex_unlock(&i915->drm.struct_mutex);
+       return err;
+
+err_wedged:
+       for (i = 0; i < ARRAY_SIZE(client); i++)
+               igt_spinner_end(&client[i].spin);
+       i915_gem_set_wedged(i915);
+       err = -EIO;
+       goto err_client_3;
+}
+
 static int live_chain_preempt(void *arg)
 {
        struct drm_i915_private *i915 = arg;
                SUBTEST(live_preempt),
                SUBTEST(live_late_preempt),
                SUBTEST(live_suppress_self_preempt),
+               SUBTEST(live_suppress_wait_preempt),
                SUBTEST(live_chain_preempt),
                SUBTEST(live_preempt_hang),
                SUBTEST(live_preempt_smoke),