[PATCH i-g-t v3 4/5] lib/igt_kms: Add helper to obtain a connector by its name or MST path

[Louis Chauvet]

Introduce the functions igt_get_connector_from_name() and
igt_get_connector_id_from_mst_path(). These functions serve to retrieve
the connector object using a connector name and a connector ID from its
MST path, respectively.

Given that the connector id may not be consistent, especially with MST
connectors, these functions are essential to recognize each connector even
after system reboots and plug/unplug events.

The function igt_get_connector_id_from_name() is a convenient wrapper for
igt_get_connector_from_name() to streamline its usage when the caller only
requires the connector id.

Signed-off-by: Louis Chauvet <louis.chauvet at bootlin.com>
---
 lib/igt_kms.c | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/igt_kms.h |   3 ++
 2 files changed, 109 insertions(+)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index 5d3f609d469d741d9fd68a9a0b41ab0162d322b6..5c242a5bdec619d181c3d0d632f1ea7d94d34743 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -7314,3 +7314,109 @@ int igt_get_connected_connectors(int drm_fd, uint32_t **connector_ids)
 	return
 	    connected_count;
 }
+
+
+/**
+ * igt_get_connector_from_name:
+ * @drm_fd: DRM file descriptor
+ * @port_name: Port name to search
+ *
+ * Returns: The connector if found, NULL otherwise. The pointer must
+ * be freed with drmModeFreeConnector()
+ */
+drmModeConnectorPtr igt_get_connector_from_name(int drm_fd, const char *port_name)
+{
+	drmModeResPtr res = drmModeGetResources(drm_fd);
+	struct timespec start, end;
+	int i;
+
+	if (!res)
+		return 0;
+
+	for (i = 0; i < res->count_connectors; i++) {
+		char name[50];
+
+		drmModeConnectorPtr connector = drmModeGetConnector(drm_fd, res->connectors[i]);
+		/*
+		 * This time is required as sometimes some id in the connector list are not totally
+		 * ready or can disappear
+		 */
+		clock_gettime(CLOCK_MONOTONIC, &start);
+		end = start;
+		while (!connector &&
+		       igt_time_elapsed(&start, &end) <= igt_default_detect_timeout()) {
+			connector = drmModeGetConnector(drm_fd, res->connectors[i]);
+			clock_gettime(CLOCK_MONOTONIC, &end);
+		}
+
+		if (igt_time_elapsed(&start, &end) <= igt_default_detect_timeout()) {
+			igt_assert(connector);
+
+			/* We have to generate the connector name on our own */
+			snprintf(name, ARRAY_SIZE(name), "%s-%u",
+				 kmstest_connector_type_str(connector->connector_type),
+				 connector->connector_type_id);
+
+			if (strcmp(port_name, name) == 0) {
+				drmModeFreeResources(res);
+				return connector;
+			}
+			drmModeFreeConnector(connector);
+		}
+	}
+	drmModeFreeResources(res);
+	return NULL;
+}
+
+/**
+ * igt_get_connector_id_from_name:
+ * @drm_fd: DRM file descriptor
+ * @port_name: Port name to find in the connector
+ *
+ * Returns: The connector id if the port is found, 0 if the port is not found
+ */
+uint32_t igt_get_connector_id_from_name(int drm_fd, const char *port_name)
+{
+	drmModeConnectorPtr connector = igt_get_connector_from_name(drm_fd, port_name);
+
+	if (connector) {
+		int connector_id = connector->connector_id;
+
+		drmModeFreeConnector(connector);
+		return connector_id;
+	}
+	return 0;
+}
+
+/**
+ * igt_get_connector_id_from_mst_path:
+ * @drm_fd: DRM file descriptor
+ * @mst_path: MST path to find in the connector
+ *
+ * Returns: 0 when no connector is found with the correct mst path
+ */
+uint32_t igt_get_connector_id_from_mst_path(int drm_fd, const void *mst_path)
+{
+	drmModeResPtr res = drmModeGetResources(drm_fd);
+	int i;
+
+	if (!res)
+		return 0;
+
+	for (i = 0; i < res->count_connectors; i++) {
+		uint32_t connector_id = res->connectors[i];
+
+		drmModePropertyBlobPtr path_blob = kmstest_get_path_blob(drm_fd, connector_id);
+
+		if (path_blob) {
+			if (strcmp(path_blob->data, mst_path) == 0) {
+				drmModeFreePropertyBlob(path_blob);
+				drmModeFreeResources(res);
+				return connector_id;
+			}
+			drmModeFreePropertyBlob(path_blob);
+		}
+	}
+	drmModeFreeResources(res);
+	return 0;
+}
diff --git a/lib/igt_kms.h b/lib/igt_kms.h
index 33079b696c070ee7b62ec1d5705b221ba4ad5a7c..d61ddcaa0a25f1f9bc34eff7314eaa49a3de9cc2 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -1278,5 +1278,8 @@ float igt_default_detect_timeout(void);
 bool igt_wait_for_connector_status(int drm_fd, unsigned int connector_id, double timeout,
 				   int drm_mode);
 int igt_get_connected_connectors(int drm_fd, uint32_t **connector_ids);
+drmModeConnectorPtr igt_get_connector_from_name(int drm_fd, const char *port_name);
+uint32_t igt_get_connector_id_from_name(int drm_fd, const char *port_name);
+uint32_t igt_get_connector_id_from_mst_path(int drm_fd, const void *mst_path);
 
 #endif /* __IGT_KMS_H__ */

-- 
2.47.0