[i-g-t v7 8/8] tests/kms_vrr: Add a max/min test to oscillate between rates

[Bhanuprakash Modem]

From: Sean Paul <seanpaul at chromium.org>

The new MAXMIN test will oscillate between the max and min
refresh rates every frame to stress test the panel. This is
useful for manual profiling of flicker.

v2:
- Added to the set
v3: (Bhanu)
- Rebase
- Add testplan documentation
v4: (Bhanu)
- Don't execute other stuff in max-min
v5: (Bhanu)
- Adjust Pass/Fail criteria
- Tweak min rate for Intel h/w

Signed-off-by: Sean Paul <seanpaul at chromium.org>
Reviewed-by: Bhanuprakash Modem <bhanuprakash.modem at intel.com>
Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem at intel.com>
---
 tests/kms_vrr.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/tests/kms_vrr.c b/tests/kms_vrr.c
index 6d516d8fc..15c62b34b 100644
--- a/tests/kms_vrr.c
+++ b/tests/kms_vrr.c
@@ -66,6 +66,10 @@
  * Description: Test to switch RR seamlessly without modeset.
  * Functionality: adaptive_sync, drrs
  *
+ * SUBTEST: max-min
+ * Description: Oscillates between highest and lowest refresh each frame for
+ *              manual flicker profiling
+ *
  * SUBTEST: negative-basic
  * Description: Make sure that VRR should not be enabled on the Non-VRR panel.
  */
@@ -86,7 +90,8 @@ enum {
 	TEST_SEAMLESS_VRR = 1 << 4,
 	TEST_SEAMLESS_DRRS = 1 << 5,
 	TEST_FASTSET = 1 << 6,
-	TEST_NEGATIVE = 1 << 7,
+	TEST_MAXMIN = 1 << 7,
+	TEST_NEGATIVE = 1 << 8,
 };
 
 enum {
@@ -537,7 +542,7 @@ test_basic(data_t *data, enum pipe pipe, igt_output_t *output, uint32_t flags)
 			     (range.max + 5), rate[0], result);
 	}
 
-	if (flags & ~TEST_NEGATIVE) {
+	if (flags & ~(TEST_NEGATIVE | TEST_MAXMIN)) {
 		rate[0] = vtest_ns.rate_ns;
 		result = flip_and_measure(data, output, pipe, rate, 1, data->duration_ns);
 		igt_assert_f(result > 75,
@@ -553,6 +558,19 @@ test_basic(data_t *data, enum pipe pipe, igt_output_t *output, uint32_t flags)
 			     (range.min - 10), rate[0], result);
 	}
 
+	if (flags & TEST_MAXMIN) {
+		unsigned int range_min =
+			/* For Intel h/w tweak the min rate, as h/w will terminate the vblank at Vmax. */
+			is_intel_device(data->drm_fd) ? (range.min + 2) : range.min;
+		uint64_t maxmin_rates[] = {vtest_ns.max, rate_from_refresh(range_min)};
+
+		result = flip_and_measure(data, output, pipe, maxmin_rates, 2, data->duration_ns);
+		igt_assert_f(result > 75,
+			     "Refresh rates (%u/%u Hz) %"PRIu64"ns/%"PRIu64"ns: Target VRR on threshold not reached, result was %u%%\n",
+			     range.max, range_min, maxmin_rates[0], maxmin_rates[1], result);
+		return;
+	}
+
 	/*
 	 * If we request VRR on a non-VRR panel, it is unlikely to reject the
 	 * modeset. And the expected behavior is the same as disabling VRR on
@@ -802,6 +820,11 @@ igt_main_args("drs:", long_opts, help_str, opt_handler, &data)
 	igt_subtest_with_dynamic("negative-basic")
 		run_vrr_test(&data, test_basic, TEST_NEGATIVE);
 
+	igt_describe("Oscillates between highest and lowest refresh each frame for manual "
+		     "flicker profiling");
+	igt_subtest_with_dynamic("max-min")
+		run_vrr_test(&data, test_basic, TEST_MAXMIN);
+
 	igt_subtest_group {
 		igt_fixture
 			igt_require_intel(data.drm_fd);
-- 
2.43.0