From f527a38ee764f57a86ceedfc105f425e56392db4 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sun, 24 Jul 2016 10:10:21 +0100 Subject: [PATCH] drm/i915: Update the breadcrumb interrupt counter before enabling In order to close a race with a long running hangcheck comparing a stale interrupt counter with a just started waiter, we need to first bump the counter as we start the fresh wait. References: https://bugs.freedesktop.org/show_bug.cgi?id=96974 Signed-off-by: Chris Wilson Cc: Joonas Lahtinen Cc: Tvrtko Ursulin Reviewed-by: Tvrtko Ursulin Link: http://patchwork.freedesktop.org/patch/msgid/1469351421-13493-2-git-send-email-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/intel_breadcrumbs.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_breadcrumbs.c b/drivers/gpu/drm/i915/intel_breadcrumbs.c index f0b56e3f4abe..d893ccdd62ac 100644 --- a/drivers/gpu/drm/i915/intel_breadcrumbs.c +++ b/drivers/gpu/drm/i915/intel_breadcrumbs.c @@ -51,6 +51,13 @@ static void irq_enable(struct intel_engine_cs *engine) */ engine->breadcrumbs.irq_posted = true; + /* Make sure the current hangcheck doesn't falsely accuse a just + * started irq handler from missing an interrupt (because the + * interrupt count still matches the stale value from when + * the irq handler was disabled, many hangchecks ago). + */ + engine->breadcrumbs.irq_wakeups++; + spin_lock_irq(&engine->i915->irq_lock); engine->irq_enable(engine); spin_unlock_irq(&engine->i915->irq_lock); -- 2.20.1