tests/kms_chamelium: add dp-audio test

This new test ensures DisplayPort audio works by using the Chamelium.

It enables the DisplayPort output and sends an audio signal containing a set of
frequencies we choose to all HDMI/DisplayPort audio devices. It starts
recording audio on the Chamelium device and uses the stream server to retrieve
captured audio pages. It then checks that the capture audio signal contains the
frequencies we sent, and only those, by computing a FFT.

A new library has been added to libigt to communicate with the stream server.
It implements a simple custom TCP protocol.

In case the test fails, a WAV file with the captured data is saved on disk.

Right now the test has a few limitations:

- Only the first channel is checked
- IGT only generates audio with a single sampling rate (48 KHz)
- Audio data is not captured in real-time

These limitations will be lifted in future patches.

PulseAudio must not run during the tests since ALSA is used directly. To ensure
this, edit /etc/pulse/client.conf and add `autospawn=no`. Then run
`pulseaudio --kill`.

This commit deletes the existing audio tests. They weren't run and required an
exotic configuration (HDMI audio splitter, dummy HDMI sink and a line-in port
on the DUT).

This patch also changes lib/igt_audio to use uint16_t instead of short. The
rationale is:

- The standard says a short is at least 16 bit wide, but a short can be
  larger (in practice it won't happen, but better use types correctly)
- It makes it clearer that the audio format is S16_LE, since "16" is
  in the type name.

This patch depends on the following Chameleon bugs:

- https://crbug.com/948060
- https://crbug.com/950857

Signed-off-by: Simon Ser <simon.ser@intel.com>
Reviewed-by: Martin Peres <martin.peres@linux.intel.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/lib/igt_audio.h b/lib/igt_audio.h
index b3b658a4..4aa43e69 100644
--- a/lib/igt_audio.h
+++ b/lib/igt_audio.h
@@ -30,6 +30,7 @@
 #include "config.h"
 
 #include <stdbool.h>
+#include <stdint.h>
 
 struct audio_signal;
 
@@ -37,8 +38,13 @@ struct audio_signal *audio_signal_init(int channels, int sampling_rate);
 int audio_signal_add_frequency(struct audio_signal *signal, int frequency);
 void audio_signal_synthesize(struct audio_signal *signal);
 void audio_signal_clean(struct audio_signal *signal);
-void audio_signal_fill(struct audio_signal *signal, short *buffer, int frames);
-bool audio_signal_detect(struct audio_signal *signal, int channels,
-			 int sampling_rate, short *buffer, int frames);
+void audio_signal_fill(struct audio_signal *signal, int16_t *buffer, int frames);
+bool audio_signal_detect(struct audio_signal *signal, int sampling_rate,
+			 double *data, size_t data_len);
+size_t audio_extract_channel_s32_le(double *dst, size_t dst_cap,
+				    int32_t *src, size_t src_len,
+				    int n_channels, int channel);
+int audio_create_wav_file_s32_le(const char *qualifier, uint32_t sample_rate,
+				 uint16_t channels, char **path);
 
 #endif