[PATCH i-g-t v2 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 | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/igt_kms.h |  3 ++
 2 files changed, 100 insertions(+)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index 44b546ae52dc..fce5666cefc6 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -7235,3 +7235,100 @@ int igt_get_connected_connectors(int drm_fd, uint32_t **connector_ids)
 	return
 	    connected_count;
 }
+
+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);
+		clock_gettime(CLOCK_MONOTONIC, &end);
+		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, 50, "%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 - Get a connector ID from a connector name
+ * @drm_fd: DRM file descriptor
+ * @port_name: Port name to find in the connector
+ *
+ * Returns 0 when no connector is found with the correct name
+ */
+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 - Get a connector ID from a 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 4674b271638a..e9732c247dea 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -1266,5 +1266,8 @@ 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__ */

-- 
2.46.2