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Commit badf1f27 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Order assert forcewake test 

Read the current value before computing the expected to ensure that if
the timer does complete early (against our will), it should not cause a
false positive.

v2: The local irq disable did not prevent the timer from running.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111074


Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190705074604.16496-1-chris@chris-wilson.co.uk
parent eef037ea

drivers/gpu/drm/i915/intel_uncore.c

+3 −4
Original line number Diff line number Diff line
@@ -758,19 +758,18 @@ void assert_forcewakes_active(struct intel_uncore *uncore, 
	 * Check that the caller has an explicit wakeref and we don't mistake

	 * it for the auto wakeref.

	 */

	local_irq_disable();

	for_each_fw_domain_masked(domain, fw_domains, uncore, tmp) {

		unsigned int actual = READ_ONCE(domain->wake_count);

		unsigned int expect = 1;



		if (hrtimer_active(&domain->timer) && READ_ONCE(domain->active))

			expect++; /* pending automatic release */



		if (WARN(domain->wake_count < expect,

		if (WARN(actual < expect,

			 "Expected domain %d to be held awake by caller, count=%d\n",

			 domain->id, domain->wake_count))

			 domain->id, actual))

			break;

	}

	local_irq_enable();

}



/* We give fast paths for the really cool registers */