+ const int last_prio = rq_prio(rq);
+
+ if (!intel_engine_has_preemption(engine))
+ return false;
+
+ if (i915_request_completed(rq))
+ return false;
+
+ /*
+ * Check if the current priority hint merits a preemption attempt.
+ *
+ * We record the highest value priority we saw during rescheduling
+ * prior to this dequeue, therefore we know that if it is strictly
+ * less than the current tail of ESLP[0], we do not need to force
+ * a preempt-to-idle cycle.
+ *
+ * However, the priority hint is a mere hint that we may need to
+ * preempt. If that hint is stale or we may be trying to preempt
+ * ourselves, ignore the request.
+ */
+ if (!__execlists_need_preempt(engine->execlists.queue_priority_hint,
+ last_prio))
+ return false;
+
+ /*
+ * Check against the first request in ELSP[1], it will, thanks to the
+ * power of PI, be the highest priority of that context.
+ */
+ if (!list_is_last(&rq->link, &engine->timeline.requests) &&
+ rq_prio(list_next_entry(rq, link)) > last_prio)
+ return true;
+
+ /*
+ * If the inflight context did not trigger the preemption, then maybe
+ * it was the set of queued requests? Pick the highest priority in
+ * the queue (the first active priolist) and see if it deserves to be
+ * running instead of ELSP[0].
+ *
+ * The highest priority request in the queue can not be either
+ * ELSP[0] or ELSP[1] as, thanks again to PI, if it was the same
+ * context, it's priority would not exceed ELSP[0] aka last_prio.
+ */
+ return queue_prio(&engine->execlists) > last_prio;
+}
+
+__maybe_unused static inline bool
+assert_priority_queue(const struct intel_engine_execlists *execlists,
+ const struct i915_request *prev,
+ const struct i915_request *next)
+{
+ if (!prev)
+ return true;
+
+ /*
+ * Without preemption, the prev may refer to the still active element
+ * which we refuse to let go.
+ *
+ * Even with preemption, there are times when we think it is better not
+ * to preempt and leave an ostensibly lower priority request in flight.
+ */
+ if (port_request(execlists->port) == prev)
+ return true;
+
+ return rq_prio(prev) >= rq_prio(next);