[PATCH v8 3/4] drm: Suppress intentional warning backtraces in scaling unit tests

[Albert Esteve]

From: Guenter Roeck <linux at roeck-us.net>

The drm_test_rect_calc_hscale and drm_test_rect_calc_vscale unit tests
intentionally trigger warning backtraces by providing bad parameters to
the tested functions. What is tested is the return value, not the existence
of a warning backtrace. Suppress the backtraces to avoid clogging the
kernel log and distraction from real problems.

Tested-by: Linux Kernel Functional Testing <lkft at linaro.org>
Acked-by: Dan Carpenter <dan.carpenter at linaro.org>
Acked-by: Maíra Canal <mcanal at igalia.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: David Airlie <airlied at gmail.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Signed-off-by: Guenter Roeck <linux at roeck-us.net>
Signed-off-by: Alessandro Carminati <acarmina at redhat.com>
Acked-by: David Gow <david at davidgow.net>
Signed-off-by: Albert Esteve <aesteve at redhat.com>
---
 drivers/gpu/drm/tests/drm_rect_test.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/tests/drm_rect_test.c b/drivers/gpu/drm/tests/drm_rect_test.c
index 17e1f34b76101..818e16e80c8f9 100644
--- a/drivers/gpu/drm/tests/drm_rect_test.c
+++ b/drivers/gpu/drm/tests/drm_rect_test.c
@@ -409,8 +409,16 @@ static void drm_test_rect_calc_hscale(struct kunit *test)
 	const struct drm_rect_scale_case *params = test->param_value;
 	int scaling_factor;
 
-	scaling_factor = drm_rect_calc_hscale(&params->src, &params->dst,
-					      params->min_range, params->max_range);
+	/*
+	 * drm_rect_calc_hscale() generates a warning backtrace whenever bad
+	 * parameters are passed to it. This affects all unit tests with an
+	 * error code in expected_scaling_factor.
+	 */
+	kunit_warning_suppress(test) {
+		scaling_factor = drm_rect_calc_hscale(&params->src, &params->dst,
+						      params->min_range,
+						      params->max_range);
+	}
 
 	KUNIT_EXPECT_EQ(test, scaling_factor, params->expected_scaling_factor);
 }
@@ -420,8 +428,15 @@ static void drm_test_rect_calc_vscale(struct kunit *test)
 	const struct drm_rect_scale_case *params = test->param_value;
 	int scaling_factor;
 
-	scaling_factor = drm_rect_calc_vscale(&params->src, &params->dst,
-					      params->min_range, params->max_range);
+	/*
+	 * drm_rect_calc_vscale() generates a warning backtrace whenever bad
+	 * parameters are passed to it. This affects all unit tests with an
+	 * error code in expected_scaling_factor.
+	 */
+	kunit_warning_suppress(test) {
+		scaling_factor = drm_rect_calc_vscale(&params->src, &params->dst,
+						      params->min_range, params->max_range);
+	}
 
 	KUNIT_EXPECT_EQ(test, scaling_factor, params->expected_scaling_factor);
 }

-- 
2.53.0