drm/i915/selftests: Disable preemption while setting up fence-timers (d2eeaf2b) · Commits · 戴 / test

The impossible happens and a future fence expired while we were still initialising. The probable cause is that the test was preempted and we lost our scheduler cpu slice. Disable preemption during this test to rule out preemption as a source of timer disruption. References: https://bugs.freedesktop.org/show_bug.cgi?id=110039 Signed-off-by:

Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by:

Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190313205944.5768-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/selftests/i915_sw_fence.c

+8 −1

Original line number	Diff line number	Diff line
		@@ -571,21 +571,27 @@ static int test_timer(void *arg)
		unsigned long target, delay;
		struct timed_fence tf;

		preempt_disable();
		timed_fence_init(&tf, target = jiffies);
		if (!i915_sw_fence_done(&tf.fence)) {
		pr_err("Fence with immediate expiration not signaled\n");
		goto err;
		}
		preempt_enable();
		timed_fence_fini(&tf);

		for_each_prime_number(delay, i915_selftest.timeout_jiffies/2) {
		preempt_disable();
		timed_fence_init(&tf, target = jiffies + delay);
		if (i915_sw_fence_done(&tf.fence)) {
		pr_err("Fence with future expiration (%lu jiffies) already signaled\n", delay);
		goto err;
		}
		preempt_enable();

		i915_sw_fence_wait(&tf.fence);

		preempt_disable();
		if (!i915_sw_fence_done(&tf.fence)) {
		pr_err("Fence not signaled after wait\n");
		goto err;
		@@ -595,13 +601,14 @@ static int test_timer(void *arg)
		target, jiffies);
		goto err;
		}

		preempt_enable();
		timed_fence_fini(&tf);
		}

		return 0;

		err:
		preempt_enable();
		timed_fence_fini(&tf);
		return -EINVAL;
		}

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