[PATCH i-g-t v4 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 | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/igt_kms.h |   3 ++
 2 files changed, 112 insertions(+)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index 93d5a0d64df9954f7da8254ee35a0fd887d31d78..f6d9341b75b4fc8dfa614478cd3bf35510f9ecea 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -93,6 +93,10 @@
 #define MAX_CONNECTORS 32
 #define MAX_EDID 2
 #define DISPLAY_TILE_BLOCK 0x12
+/**
+ * define IGT_KMS_CONNECTOR_NAME_SIZE - Size used when a connector name is needed
+ */
+#define IGT_KMS_CONNECTOR_NAME_SIZE 50
 
 typedef bool (*igt_connector_attr_set)(int dir, const char *attr, const char *value);
 
@@ -7349,3 +7353,108 @@ 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);
+	double timeout = igt_default_display_detect_timeout();
+	int i, len;
+
+	if (!res)
+		return NULL;
+
+	for (i = 0; i < res->count_connectors; i++) {
+		char name[IGT_KMS_CONNECTOR_NAME_SIZE];
+
+		drmModeConnectorPtr connector = igt_wait_for_connector(drm_fd, res->connectors[i],
+								       timeout);
+
+		if (connector) {
+			/* We have to generate the connector name on our own */
+			len = snprintf(name, ARRAY_SIZE(name), "%s-%u",
+				 kmstest_connector_type_str(connector->connector_type),
+				 connector->connector_type_id);
+			name[len] = 0;
+
+
+			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) {
+		uint32_t 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 (memcmp(path_blob->data, mst_path, path_blob->length) == 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 520d1b2f2056a21bcf25be36da32a63a17bfe364..3be9068384aa118461dd090224d15aa5c979ac06 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -1282,5 +1282,8 @@ double igt_default_display_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__ */

-- 
2.47.1