[Intel-gfx] [PATCH v4 3/4] drm/i915/selftest: Always cancel semaphore on error

[Ramalingam C]

From: Chris Wilson <chris at chris-wilson.co.uk>

Ensure that we always signal the semaphore when timing out, so that if it
happens to be stuck waiting for the semaphore we will quickly recover
without having to wait for a reset.

Reported-by: CQ Tang <cq.tang at intel.com>
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: CQ Tang <cq.tang at intel.com>
cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
Reviewed-by: Thomas Hellstrom <thomas.hellstrom at linux.intel.com>
---
 drivers/gpu/drm/i915/gt/selftest_lrc.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
index 3271f01fe7db..e4d5d74489bf 100644
--- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
@@ -1460,18 +1460,17 @@ static int __lrc_isolation(struct intel_engine_cs *engine, u32 poison)
 	}
 
 	err = poison_registers(B, poison, sema);
-	if (err) {
-		WRITE_ONCE(*sema, -1);
-		i915_request_put(rq);
-		goto err_result1;
-	}
-
-	if (i915_request_wait(rq, 0, HZ / 2) < 0) {
-		i915_request_put(rq);
+	if (err == 0 && i915_request_wait(rq, 0, HZ / 2) < 0) {
+		pr_err("%s(%s): wait for results timed out\n",
+		       __func__, engine->name);
 		err = -ETIME;
-		goto err_result1;
 	}
+
+	/* Always cancel the semaphore wait, just in case the GPU gets stuck */
+	WRITE_ONCE(*sema, -1);
 	i915_request_put(rq);
+	if (err)
+		goto err_result1;
 
 	err = compare_isolation(engine, ref, result, A, poison);
 
-- 
2.20.1