[Intel-gfx] [CI 1/3] drm/i915/selftests: Serialise nop reset with retirement

[Chris Wilson]

In order for the reset count to be accurate across our selftest, we need
to prevent the background retire worker from modifying our expected
state. To preserve the intent of symmetry, we apply this to both
i915_reset and i915_reset_engine, even though it strictly only affects
i915_reset_engine currently.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
---
 drivers/gpu/drm/i915/gt/selftest_hangcheck.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
index 3ceb397c8645..0e0b6c572ae9 100644
--- a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
+++ b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
@@ -398,6 +398,7 @@ static int igt_reset_nop(void *arg)
 	count = 0;
 	do {
 		mutex_lock(&i915->drm.struct_mutex);
+
 		for_each_engine(engine, i915, id) {
 			int i;
 
@@ -413,11 +414,12 @@ static int igt_reset_nop(void *arg)
 				i915_request_add(rq);
 			}
 		}
-		mutex_unlock(&i915->drm.struct_mutex);
 
 		igt_global_reset_lock(i915);
 		i915_reset(i915, ALL_ENGINES, NULL);
 		igt_global_reset_unlock(i915);
+
+		mutex_unlock(&i915->drm.struct_mutex);
 		if (i915_reset_failed(i915)) {
 			err = -EIO;
 			break;
@@ -511,9 +513,8 @@ static int igt_reset_nop_engine(void *arg)
 
 				i915_request_add(rq);
 			}
-			mutex_unlock(&i915->drm.struct_mutex);
-
 			err = i915_reset_engine(engine, NULL);
+			mutex_unlock(&i915->drm.struct_mutex);
 			if (err) {
 				pr_err("i915_reset_engine failed\n");
 				break;
-- 
2.20.1