[PATCH i-g-t v1 02/25] lib/igt_kms: Add helper to wait for a specific status on a connector

[Mohammed Bilal <mohammed.bilal@intel.com>]

From: Louis Chauvet <louis.chauvet@bootlin.com>

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.

Reviewed-by: Kory Maincent <kory.maincent@bootlin.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@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 ece888d1a..25184531b 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -8214,3 +8214,42 @@ 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) {
+			free(connector);
+			return true;
+		}
+		free(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 b10df1d8d..60cfc1763 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -1299,4 +1299,7 @@ igt_colorop_t *igt_find_colorop(igt_display_t *display, uint32_t id);
 
 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__ */
-- 
2.48.1