[Intel-gfx] [PATCH i-g-t] tests/chamelium: Detect analogue bridges and handle EDID accordingly

[Paul Kocialkowski]

Nowadays, many VGA connectors are not actually native VGA but use a
discrete bridge to a digital connector. These bridges usually enforce
their own EDID instead of the one supplied by the chamelium.

Thus, the EDID read test for VGA is not relevant in that case and
should be skipped. Reported modes may also go beyond what the chamelium
can support. Thus, only supported resolutions should be tested for the
frame dump test and others should be pruned.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski at linux.intel.com>
---
 tests/chamelium.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)

diff --git a/tests/chamelium.c b/tests/chamelium.c
index 5ccdee7c..d26846ba 100644
--- a/tests/chamelium.c
+++ b/tests/chamelium.c
@@ -106,6 +106,76 @@ wait_for_connector(data_t *data, struct chamelium_port *port,
 	igt_assert(finished);
 }
 
+static int chamelium_vga_modes[][2] = {
+	{ 1600, 1200 },
+	{ 1920, 1200 },
+	{ 1920, 1080 },
+	{ 1680, 1050 },
+	{ 1280, 1024 },
+	{ 1280, 960 },
+	{ 1440, 900 },
+	{ 1280, 800 },
+	{ 1024, 768 },
+	{ 1360, 768 },
+	{ 1280, 720 },
+	{ 800, 600 },
+	{ 640, 480 },
+	{ -1, -1 },
+};
+
+static bool
+prune_vga_mode(data_t *data, drmModeModeInfo *mode)
+{
+	int i = 0;
+
+	while (chamelium_vga_modes[i][0] != -1) {
+		if (mode->hdisplay == chamelium_vga_modes[i][0] &&
+		    mode->vdisplay == chamelium_vga_modes[i][1])
+			return false;
+
+		i++;
+	}
+
+	return true;
+}
+
+static bool
+check_analogue_bridge(data_t *data, struct chamelium_port *port)
+{
+	drmModePropertyBlobPtr edid_blob = NULL;
+	drmModeConnector *connector = chamelium_port_get_connector(
+	    data->chamelium, port, false);
+	uint64_t edid_blob_id;
+	unsigned char *edid;
+	char edid_vendor[3];
+
+	if (chamelium_port_get_type(port) != DRM_MODE_CONNECTOR_VGA)
+		return false;
+
+	igt_assert(kmstest_get_property(data->drm_fd, connector->connector_id,
+					DRM_MODE_OBJECT_CONNECTOR, "EDID", NULL,
+					&edid_blob_id, NULL));
+	igt_assert(edid_blob = drmModeGetPropertyBlob(data->drm_fd,
+						      edid_blob_id));
+
+	edid = (unsigned char *) edid_blob->data;
+
+	edid_vendor[0] = ((edid[8] & 0x7c) >> 2) + '@';
+	edid_vendor[1] = (((edid[8] & 0x03) << 3) |
+			  ((edid[9] & 0xe0) >> 5)) + '@';
+	edid_vendor[2] = (edid[9] & 0x1f) + '@';
+
+	/* Analogue bridges provide their own EDID */
+	if (edid_vendor[0] != 'I' || edid_vendor[1] != 'G' ||
+	    edid_vendor[0] != 'T')
+		return true;
+
+	drmModeFreePropertyBlob(edid_blob);
+	drmModeFreeConnector(connector);
+
+	return false;
+}
+
 static void
 reset_state(data_t *data, struct chamelium_port *port)
 {
@@ -170,6 +240,8 @@ test_edid_read(data_t *data, struct chamelium_port *port,
 	chamelium_plug(data->chamelium, port);
 	wait_for_connector(data, port, DRM_MODE_CONNECTED, true);
 
+	igt_skip_on(check_analogue_bridge(data, port));
+
 	igt_assert(kmstest_get_property(data->drm_fd, connector->connector_id,
 					DRM_MODE_OBJECT_CONNECTOR, "EDID", NULL,
 					&edid_blob_id, NULL));
@@ -487,6 +559,7 @@ test_analogue_frame_dump(data_t *data, struct chamelium_port *port)
 	const char *connector_name;
 	char *frame_dump_path;
 	char path[PATH_MAX];
+	bool bridge;
 	bool eq;
 
 	output = prepare_output(data, &display, port);
@@ -497,9 +570,14 @@ test_analogue_frame_dump(data_t *data, struct chamelium_port *port)
 	connector_name = kmstest_connector_type_str(connector->connector_type);
 	frame_dump_path = chamelium_get_frame_dump_path(data->chamelium);
 
+	bridge = check_analogue_bridge(data, port);
+
 	for (i = 0; i < connector->count_modes; i++) {
 		mode = &connector->modes[i];
 
+		if (bridge && prune_vga_mode(data, mode))
+			continue;
+
 		fb_id = igt_create_color_pattern_fb(data->drm_fd,
 						    mode->hdisplay, mode->vdisplay,
 						    DRM_FORMAT_XRGB8888,
-- 
2.13.2