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, 11 insertions, 0 deletions

diff --git a/lib/igt_chamelium.h b/lib/igt_chamelium.h
index 233ead85..047f8c5d 100644
--- a/lib/igt_chamelium.h
+++ b/lib/igt_chamelium.h
@@ -53,6 +53,12 @@ enum chamelium_check {
 	CHAMELIUM_CHECK_CRC,
 };
 
+struct chamelium_audio_file {
+	char *path;
+	int rate; /* Hz */
+	int channels;
+};
+
 struct chamelium *chamelium_init(int drm_fd);
 void chamelium_deinit(struct chamelium *chamelium);
 void chamelium_reset(struct chamelium *chamelium);
@@ -100,6 +106,10 @@ void chamelium_start_capture(struct chamelium *chamelium,
 void chamelium_stop_capture(struct chamelium *chamelium, int frame_count);
 void chamelium_capture(struct chamelium *chamelium, struct chamelium_port *port,
 		       int x, int y, int w, int h, int frame_count);
+void chamelium_start_capturing_audio(struct chamelium *chamelium,
+				    struct chamelium_port *port, bool save_to_file);
+struct chamelium_audio_file *chamelium_stop_capturing_audio(struct chamelium *chamelium,
+							    struct chamelium_port *port);
 igt_crc_t *chamelium_read_captured_crcs(struct chamelium *chamelium,
 					int *frame_count);
 struct chamelium_frame_dump *chamelium_read_captured_frame(struct chamelium *chamelium,
@@ -131,5 +141,6 @@ void chamelium_assert_frame_match_or_dump(struct chamelium *chamelium,
 void chamelium_crop_analog_frame(struct chamelium_frame_dump *dump, int width,
 				 int height);
 void chamelium_destroy_frame_dump(struct chamelium_frame_dump *dump);
+void chamelium_destroy_audio_file(struct chamelium_audio_file *audio_file);
 
 #endif /* IGT_CHAMELIUM_H */