[i-g-t 1/2] tests/kms_vrr: Enhance flip accuracy measurement
Bhanuprakash Modem
bhanuprakash.modem at intel.com
Wed Jan 17 06:33:38 UTC 2024
The threshold of ~50us, which is roughly the difference between
144Hz & 143Hz, to be too high for high refresh rate panels (like
60-360Hz) and too low for low refresh rate panels (like 40-60Hz)
when measuring flip accuracy.
Revise the threshold to allow for a deviation of approximately
(+/-) 1 Hz will improve the accuracy of flip measurements across
a wider range of panel refresh rates.
Cc: Mitul Golani <mitulkumar.ajitkumar.golani at intel.com>
Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem at intel.com>
---
tests/kms_vrr.c | 27 ++++++++++++++++-----------
1 file changed, 16 insertions(+), 11 deletions(-)
diff --git a/tests/kms_vrr.c b/tests/kms_vrr.c
index 71fc36162..44bc3480d 100644
--- a/tests/kms_vrr.c
+++ b/tests/kms_vrr.c
@@ -339,10 +339,23 @@ static uint32_t
flip_and_measure(data_t *data, igt_output_t *output, enum pipe pipe,
uint64_t rate_ns, uint64_t duration_ns)
{
- uint64_t start_ns, last_event_ns, target_ns;
+ uint64_t start_ns, last_event_ns, target_ns, exp_rate_ns;
uint32_t total_flip = 0, total_pass = 0;
bool front = false;
vtest_ns_t vtest_ns = get_test_rate_ns(data->range);
+ uint64_t threshold_hi, threshold_lo;
+
+ if ((rate_ns <= vtest_ns.min) && (rate_ns >= vtest_ns.max))
+ exp_rate_ns = rate_ns;
+ else
+ exp_rate_ns = vtest_ns.max;
+
+ /* Allow ~1 Hz deviation for different reasons causing delay. */
+ threshold_hi = NSECS_PER_SEC / (((float)NSECS_PER_SEC / exp_rate_ns) + 1);
+ threshold_lo = NSECS_PER_SEC / (((float)NSECS_PER_SEC / exp_rate_ns) - 1);
+
+ igt_info("Requested rate: %"PRIu64" ns, Expected rate between: %"PRIu64" ns to %"PRIu64" ns\n",
+ rate_ns, threshold_hi, threshold_lo);
/* Align with the flip completion event to speed up convergence. */
do_flip(data, &data->fb0);
@@ -369,18 +382,10 @@ flip_and_measure(data_t *data, igt_output_t *output, enum pipe pipe,
/*
* Check if the difference between the two flip timestamps
* was within the required threshold from the expected rate.
- *
- * A ~50us threshold is arbitrary, but it's roughly the
- * difference between 144Hz and 143Hz which should give this
- * enough accuracy for most use cases.
*/
- if ((rate_ns <= vtest_ns.min) && (rate_ns >= vtest_ns.max))
- diff_ns = rate_ns;
- else
- diff_ns = vtest_ns.max;
- diff_ns -= event_ns - last_event_ns;
+ diff_ns = event_ns - last_event_ns;
- if (llabs(diff_ns) < 50000ll)
+ if (llabs(diff_ns) < threshold_lo && llabs(diff_ns) > threshold_hi)
total_pass += 1;
last_event_ns = event_ns;
--
2.40.0
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