From: jsg <jsg@openbsd.org>
Date: Mon, 24 Jun 2024 03:49:19 +0000 (+0000)
Subject: drm/i915/gt: Disarm breadcrumbs if engines are already idle
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=9f286b8148825517cfbf2f56c813dedc497e5c3d;p=openbsd

drm/i915/gt: Disarm breadcrumbs if engines are already idle

From Chris Wilson
1d2f1123a05e3e269cd7564005b0b717f2014437 in linux-6.6.y/6.6.35
70cb9188ffc75e643debf292fcddff36c9dbd4ae in mainline linux
---

diff --git a/sys/dev/pci/drm/i915/gt/intel_breadcrumbs.c b/sys/dev/pci/drm/i915/gt/intel_breadcrumbs.c
index f9d88fa8bd6..46b6d0fad67 100644
--- a/sys/dev/pci/drm/i915/gt/intel_breadcrumbs.c
+++ b/sys/dev/pci/drm/i915/gt/intel_breadcrumbs.c
@@ -260,8 +260,13 @@ static void signal_irq_work(struct irq_work *work)
 		i915_request_put(rq);
 	}
 
+	/* Lazy irq enabling after HW submission */
 	if (!READ_ONCE(b->irq_armed) && !list_empty(&b->signalers))
 		intel_breadcrumbs_arm_irq(b);
+
+	/* And confirm that we still want irqs enabled before we yield */
+	if (READ_ONCE(b->irq_armed) && !atomic_read(&b->active))
+		intel_breadcrumbs_disarm_irq(b);
 }
 
 struct intel_breadcrumbs *
@@ -312,13 +317,7 @@ void __intel_breadcrumbs_park(struct intel_breadcrumbs *b)
 		return;
 
 	/* Kick the work once more to drain the signalers, and disarm the irq */
-	irq_work_sync(&b->irq_work);
-	while (READ_ONCE(b->irq_armed) && !atomic_read(&b->active)) {
-		local_irq_disable();
-		signal_irq_work(&b->irq_work);
-		local_irq_enable();
-		cond_resched();
-	}
+	irq_work_queue(&b->irq_work);
 }
 
 void intel_breadcrumbs_free(struct kref *kref)
@@ -401,7 +400,7 @@ static void insert_breadcrumb(struct i915_request *rq)
 	 * the request as it may have completed and raised the interrupt as
 	 * we were attaching it into the lists.
 	 */
-	if (!b->irq_armed || __i915_request_is_complete(rq))
+	if (!READ_ONCE(b->irq_armed) || __i915_request_is_complete(rq))
 		irq_work_queue(&b->irq_work);
 }