The target is that we report the vblank time accurate to within a scanline (limit of the hw with which we can reliably compensate).
Signed-off-by: Chris Wilson <[email protected]> --- tests/kms_setmode.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/tests/kms_setmode.c b/tests/kms_setmode.c index 9dafca0..e1e1893 100644 --- a/tests/kms_setmode.c +++ b/tests/kms_setmode.c @@ -417,6 +417,11 @@ static double frame_time(const drmModeModeInfo *kmode) return 1000.0 * kmode->htotal * kmode->vtotal / kmode->clock; } +static double line_time(const drmModeModeInfo *kmode) +{ + return 1000.0 * kmode->htotal / kmode->clock; +} + static void check_timings(int crtc_idx, const drmModeModeInfo *kmode) { #define CALIBRATE_TS_STEPS 120 /* ~2s has to be less than 128! */ @@ -425,6 +430,7 @@ static void check_timings(int crtc_idx, const drmModeModeInfo *kmode) uint32_t last_seq; uint64_t last_timestamp; double expected; + double accuracy; double mean; double stddev; int n; @@ -470,15 +476,21 @@ static void check_timings(int crtc_idx, const drmModeModeInfo *kmode) mean = igt_stats_get_mean(&stats); stddev = igt_stats_get_std_deviation(&stats); + accuracy = 3.090 * stddev; /* 2-tailed 99% confidence */ + + igt_info("Expected frametime: %.0fus; measured %.1fus +- %.3fus accuracy %.2f%% [%.2f scanlines]\n", + expected, mean, stddev, + 100 * accuracy / mean, accuracy / line_time(kmode)); - igt_info("Expected frametime: %.0fus; measured %.1fus +- %.3fus accuracy %.2f%%\n", - expected, mean, stddev, 100 * 6 * stddev / mean); - igt_assert(6 * stddev / mean < 0.005); /* 99% accuracy within 0.5% */ + /* 99% accuracy within one scanline */ + igt_assert_f(accuracy < line_time(kmode), + "vblank accuracy (%.3fus, %.1f%%) worse than a scanline (%.3fus)\n", + accuracy, 100 * accuracy / mean, line_time(kmode)); igt_assert_f(fabs(mean - expected) < 2*stddev, - "vblank interval differs from modeline! expected %.1fus, measured %1.fus +- %.3fus, difference %.1fus (%.1f sigma)\n", - expected, mean, stddev, - fabs(mean - expected), fabs(mean - expected) / stddev); + "vblank interval differs from modeline! expected %.1fus, measured %1.fus +- %.3fus, difference %.1fus (%.1f sigma)\n", + expected, mean, stddev, + fabs(mean - expected), fabs(mean - expected) / stddev); } static void test_crtc_config(const struct test_config *tconf, -- 2.10.2 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
