When cancelling the requests and clearing out the ports following a
successful preemption completion, also clear the active flag. I had
assumed that all preemptions would be followed by an immediate dequeue
(preserving the active user flag), but under rare circumstances we may
be triggering a preemption for the second port only for it to have
completed before the preemotion kicks in; leaving execlists->active set
even though the system is now idle.
We can clear the flag inside the common execlists_cancel_port_requests()
as the other users also expect the semantics of active being cleared.
Fixes: f6322eddaff7 ("drm/i915/preemption: Allow preemption between submission ports")
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Michał Winiarski <michal.winiarski@xxxxxxxxx>
Cc: Michel Thierry <michel.thierry@xxxxxxxxx>
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_lrc.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 08d8ac9d1f8f..f9edfe4540e2 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -577,6 +577,8 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
* know the next preemption status we see corresponds
* to this ELSP update.
*/
+ GEM_BUG_ON(!execlists_is_active(execlists,
+ EXECLISTS_ACTIVE_USER));
GEM_BUG_ON(!port_count(&port[0]));
if (port_count(&port[0]) > 1)
goto unlock;
@@ -738,6 +740,8 @@ execlists_cancel_port_requests(struct intel_engine_execlists * const execlists)
memset(port, 0, sizeof(*port));
port++;
}
+
+ execlists_clear_active(execlists, EXECLISTS_ACTIVE_USER);
}
static void clear_gtiir(struct intel_engine_cs *engine)
@@ -1042,6 +1046,11 @@ static void execlists_submission_tasklet(unsigned long data)
if (fw)
intel_uncore_forcewake_put(dev_priv, execlists->fw_domains);
+
+ /* If the engine is now idle, so should be the flag; and vice versa. */
+ GEM_BUG_ON(execlists_is_active(&engine->execlists,
+ EXECLISTS_ACTIVE_USER) ==
+ !port_isset(engine->execlists.port));
}
static void queue_request(struct intel_engine_cs *engine,
--
2.16.3
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