Re: [igt-dev] [PATCH i-g-t v2] tests/kms_setmode: degrade assert to debug

[Hamza Mahfooz <hamza.mahfooz@amd.com>]

[Adding Petri and Siqueira]

On 2022-09-13 11:08, Hamza Mahfooz wrote:
> Unfortunately, there are too many sources of jitter that can cause the
> vblank interval approximation obtained from DRM_IOCTL_WAIT_VBLANK to be
> off by more than a scanline for this assert to be useful. So, to allow
> this test to pass consistently degrade the assert to a debug.
> 
> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
> ---
> v2: fix logic
> ---
>   tests/kms_setmode.c | 12 ++++++------
>   1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/tests/kms_setmode.c b/tests/kms_setmode.c
> index bfa10891..58abfe14 100644
> --- a/tests/kms_setmode.c
> +++ b/tests/kms_setmode.c
> @@ -527,12 +527,12 @@ static void check_timings(int crtc_idx, const drmModeModeInfo *kmode)
>   	 * See:
>   	 * https://en.wikipedia.org/wiki/Standard_deviation#Rules_for_normally_distributed_data
>   	 */
> -	igt_assert_f(fabs(mean - expected) < max(line_time(kmode), 1.718 * stddev),
> -		     "vblank interval differs from modeline! expected %.1fus, measured %1.fus +- %.3fus, difference %.1fus (%.1f sigma, %.1f scanlines)\n",
> -		     expected, mean, stddev,
> -		     fabs(mean - expected),
> -		     fabs(mean - expected) / stddev,
> -		     fabs(mean - expected) / line_time(kmode));
> +	if (fabs(mean - expected) > max(line_time(kmode), 1.718 * stddev))
> +		igt_info("vblank interval differs from modeline! expected %.1fus, measured %1.fus +- %.3fus, difference %.1fus (%.1f sigma, %.1f scanlines)\n",
> +			 expected, mean, stddev,
> +			 fabs(mean - expected),
> +			 fabs(mean - expected) / stddev,
> +			 fabs(mean - expected) / line_time(kmode));
>   }
>   
>   static void test_crtc_config(const struct test_config *tconf,

-- 
Hamza