[PATCH i-g-t v2 02/26] lib/igt_kms: Add helper to wait for a specific status on a connector

[Louis Chauvet]

During testing with chamelium, it is frequent to wait for a specific
connector status. This new helper is polling the DRM API to wait for this
status. This allows detecting it without notifier systems which can fail
if hot plug detection is not working properly on the device under test.

Signed-off-by: Louis Chauvet <louis.chauvet at bootlin.com>
---
 lib/igt_kms.c | 39 +++++++++++++++++++++++++++++++++++++++
 lib/igt_kms.h |  3 +++
 2 files changed, 42 insertions(+)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index d0dcce5d008eb0e1953a2b60a6670c98562ba7a1..ad3a31b7a487f986083c6648e2cc1f5f14d5b4a2 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -7507,3 +7507,42 @@ double igt_default_display_detect_timeout(void)
 
 	return timeout;
 }
+
+/**
+ * igt_wait_for_connector_status:
+ * @drm_fd: drm file descriptor
+ * @connector_id: connector to monitor
+ * @timeout: maximum duration to wait, in second. Use -1.0 to set the timeout
+ *           to igt_default_detect_timeout().
+ * @drm_mode: mode to wait for, see enum drmModeConnection
+ *
+ * Wait for at most @timeout that the connector @connector_id  status
+ * become @drm_mode
+ * Returns: true when the status is reached, false if there is a timeout
+ */
+bool igt_wait_for_connector_status(int drm_fd, unsigned int connector_id, double timeout,
+				   int drm_mode)
+{
+	drmModeConnector *connector;
+	struct timespec start, end;
+
+	if (timeout == -1.0)
+		timeout = igt_default_display_detect_timeout();
+
+	clock_gettime(CLOCK_MONOTONIC, &start);
+	end = start;
+
+	while (igt_time_elapsed(&start, &end) <= timeout) {
+		connector = drmModeGetConnector(drm_fd, connector_id);
+		if (connector && connector->connection == drm_mode) {
+			drmModeFreeConnector(connector);
+			return true;
+		}
+		drmModeFreeConnector(connector);
+		clock_gettime(CLOCK_MONOTONIC, &end);
+	}
+
+	igt_debug("Timeout waiting for connection status %d on connector %d\n", drm_mode,
+		  connector_id);
+	return false;
+}
diff --git a/lib/igt_kms.h b/lib/igt_kms.h
index e39745b0a68cbac4bd57c4c4ceae82a64cfab5a9..1a2ecfd154769e5fcc755f126cd1e9c8dd1bc7c2 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -1291,4 +1291,7 @@ int igt_backlight_write(int value, const char *fname, igt_backlight_context_t *c
 
 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);
+
 #endif /* __IGT_KMS_H__ */

-- 
2.50.0