[PATCH 1/9] drm/i915: Order assert forcewake test

Chris Wilson chris at chris-wilson.co.uk
Thu Jul 4 23:11:38 UTC 2019


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.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/intel_uncore.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 2042c94c9cc9..c83bfaae377f 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -760,14 +760,15 @@ void assert_forcewakes_active(struct intel_uncore *uncore,
 	 */
 	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();
-- 
2.20.1



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