[igt-dev] [PATCH i-g-t 2/2] lib/igt_audio: sanity-check generated signals

Simon Ser
2019-05-17T10:12:05Z

This is a safety net to ensure we haven't completely messed up our signal
generation. It would be unfortunate to send e.g. a null signal after a
refactoring.

Signed-off-by: Simon Ser <simon.ser@intel.com>
---
lib/igt_audio.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)

diff --git a/lib/igt_audio.c b/lib/igt_audio.c
index f6c8e399e345..0d7422c6f3ec 100644
--- a/lib/igt_audio.c
+++ b/lib/igt_audio.c
@@ -213,6 +213,34 @@ static size_t audio_signal_count_freqs(struct audio_signal *signal, int channel)
return n;
}

+/** audio_sanity_check:
+ *
+ * Make sure our generated signal is not messed up. In particular, make sure
+ * the maximum reaches a reasonable value but doesn't exceed our
+ * SYNTHESIZE_AMPLITUDE limit. Same for the minimum.
+ *
+ * We want the signal to be powerful enough to be able to hear something. We
+ * want the signal not to reach 1.0 so that we're sure it won't get capped by
+ * the audio card or the receiver.
+ */
+static void audio_sanity_check(double *samples, size_t samples_len)
+{
+ size_t i;
+ double min = 0, max = 0;
+
+ for (i = 0; i < samples_len; i++) {
+ if (samples[i] < min)
+ min = samples[i];
+ if (samples[i] > max)
+ max = samples[i];
+ }
+
+ igt_assert(-SYNTHESIZE_AMPLITUDE <= min);
+ igt_assert(min <= -SYNTHESIZE_AMPLITUDE + 0.2);
+ igt_assert(SYNTHESIZE_AMPLITUDE - 0.2 <= max);
+ igt_assert(max <= SYNTHESIZE_AMPLITUDE);
+}
+
/**
* audio_signal_fill:
* @signal: The target signal structure
@@ -268,6 +296,8 @@ void audio_signal_fill(struct audio_signal *signal, double *buffer,
total += count;
}
}
+
+ audio_sanity_check(buffer, signal->channels * samples);
}

void audio_signal_fill_s16_le(struct audio_signal *signal, int16_t *buffer,
--
2.21.0