[PATCH i-g-t v3 02/29] 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 11e957171a1000889601d56b2c12af9d3d95f754..f24fa52ae715607515c18962f30e1c45d5860303 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -7572,3 +7572,42 @@ 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 83d1ed427cdf39875a8f9db48b17eb20978ebfc2..02c68737fd68a3dfee9aeba17489a17300e0bf67 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -1299,4 +1299,7 @@ drmModePropertyBlobRes *igt_get_writeback_formats_blob(igt_output_t *output);
 
 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__ */

-- 
2.50.1