[igt-dev] [PATCH i-g-t] tests/kms_chamelium: add a hotplug test with active connector

[Simon Ser]

This test enables a connector, unplugs it, re-plugs it, and makes sure the
Chamelium board still receives a video signal.

Legacy userspace doesn't necessarily handle hotplug uevents. This test makes
sure we don't break it.

See [1] and [2] for more context.

[1]: https://lists.freedesktop.org/archives/igt-dev/2019-July/015071.html
[2]: https://bugs.freedesktop.org/show_bug.cgi?id=111045

Signed-off-by: Simon Ser <simon.ser at intel.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Imre Deak <imre.deak at intel.com>
---

We should probably skip this test on DP-MST and USB-C?

 tests/kms_chamelium.c | 84 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)

diff --git a/tests/kms_chamelium.c b/tests/kms_chamelium.c
index f25d13c6e7c3..5cb9a3b9b363 100644
--- a/tests/kms_chamelium.c
+++ b/tests/kms_chamelium.c
@@ -862,6 +862,80 @@ static void test_mode_timings(data_t *data, struct chamelium_port *port)
 	drmModeFreeConnector(connector);
 }

+#define WAIT_VIDEO_INPUT_STABLE_TIMEOUT 5 /* seconds */
+
+/** test_hotplug_while_active:
+ *
+ * Plug a connector, enable it, unplug it, re-plug it and check we still have a
+ * stable input signal.
+ *
+ * Legacy userspace that doesn't consume hotplug events rely on this behaviour.
+ */
+static void
+test_hotplug_while_active(data_t *data, struct chamelium_port *port)
+{
+	struct udev_monitor *mon = igt_watch_hotplug();
+	igt_output_t *output;
+	drmModeConnector *connector;
+	igt_plane_t *primary;
+	struct igt_fb fb;
+	drmModeModeInfo *mode;
+	unsigned int fb_id;
+	bool ok;
+
+	reset_state(data, port);
+
+	igt_flush_hotplugs(mon);
+
+	chamelium_plug(data->chamelium, port);
+	igt_assert(igt_hotplug_detected(mon, HOTPLUG_TIMEOUT));
+	igt_assert_eq(reprobe_connector(data, port), DRM_MODE_CONNECTED);
+
+	output = prepare_output(data, port, TEST_EDID_BASE);
+	connector = chamelium_port_get_connector(data->chamelium, port, false);
+	primary = igt_output_get_plane_type(output, DRM_PLANE_TYPE_PRIMARY);
+	igt_assert(primary);
+
+	igt_assert(connector->count_modes > 0);
+	mode = &connector->modes[0];
+
+	fb_id = igt_create_color_pattern_fb(data->drm_fd,
+					    mode->hdisplay, mode->vdisplay,
+					    DRM_FORMAT_XRGB8888,
+					    LOCAL_DRM_FORMAT_MOD_NONE,
+					    0, 0, 0, &fb);
+	igt_assert(fb_id > 0);
+
+	enable_output(data, port, output, mode, &fb);
+
+	ok = chamelium_port_wait_video_input_stable(data->chamelium, port,
+						    WAIT_VIDEO_INPUT_STABLE_TIMEOUT);
+	igt_assert_f(ok, "Failed to wait for video input to become stable "
+		     "after hotplug\n");
+
+	igt_flush_hotplugs(mon);
+
+	/* Unplug and re-plug the connector without disabling the output. */
+	chamelium_unplug(data->chamelium, port);
+	igt_assert_f(igt_hotplug_detected(mon, HOTPLUG_TIMEOUT),
+		     "Expected hotplug event after unplug\n");
+	igt_assert_eq(reprobe_connector(data, port), DRM_MODE_DISCONNECTED);
+
+	igt_flush_hotplugs(mon);
+
+	chamelium_plug(data->chamelium, port);
+	igt_assert_f(igt_hotplug_detected(mon, HOTPLUG_TIMEOUT),
+		     "Expected hotplug event after unplug-replug sequence\n");
+	igt_assert_eq(reprobe_connector(data, port), DRM_MODE_CONNECTED);
+
+	ok = chamelium_port_wait_video_input_stable(data->chamelium, port,
+						    WAIT_VIDEO_INPUT_STABLE_TIMEOUT);
+	igt_assert_f(ok, "Failed to wait for video input to become stable "
+		     "after unplug and re-plug\n");
+
+	igt_cleanup_hotplug(mon);
+}
+

 /* Playback parameters control the audio signal we synthesize and send */
 #define PLAYBACK_CHANNELS 2
@@ -2267,6 +2341,9 @@ igt_main
 			test_basic_hotplug(&data, port,
 					   HPD_TOGGLE_COUNT_FAST);

+		connector_subtest("dp-hpd-active", DisplayPort)
+			test_hotplug_while_active(&data, port);
+
 		connector_subtest("dp-edid-read", DisplayPort) {
 			test_edid_read(&data, port, TEST_EDID_BASE);
 			test_edid_read(&data, port, TEST_EDID_ALT);
@@ -2345,6 +2422,9 @@ igt_main
 			test_basic_hotplug(&data, port,
 					   HPD_TOGGLE_COUNT_FAST);

+		connector_subtest("hdmi-hpd-active", HDMIA)
+			test_hotplug_while_active(&data, port);
+
 		connector_subtest("hdmi-edid-read", HDMIA) {
 			test_edid_read(&data, port, TEST_EDID_BASE);
 			test_edid_read(&data, port, TEST_EDID_ALT);
@@ -2501,6 +2581,10 @@ igt_main
 		connector_subtest("vga-hpd-fast", VGA)
 			test_basic_hotplug(&data, port, HPD_TOGGLE_COUNT_FAST);

+		connector_subtest("vga-hpd-active", VGA)
+			test_hotplug_while_active(&data, port);
+
+
 		connector_subtest("vga-edid-read", VGA) {
 			test_edid_read(&data, port, TEST_EDID_BASE);
 			test_edid_read(&data, port, TEST_EDID_ALT);
--
2.22.0