[PATCH i-g-t 7/9] lib/igt_kms: add function to check force link training failure support

[Kunal Joshi <kunal1.joshi@intel.com>]

add function to check if output supports forcing link training failures

Signed-off-by: Kunal Joshi <kunal1.joshi@intel.com>
---
 lib/igt_kms.c | 23 +++++++++++++++++++++++
 lib/igt_kms.h |  1 +
 2 files changed, 24 insertions(+)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index 4b354826d..be5d7d4fa 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -6933,3 +6933,26 @@ void igt_read_link_training_info(int drm_fd, igt_output_t *output,
 				&link_training_info->seq_train_failures) == 5);
 	link_training_info->retrain_disabled = strcmp(retrain_disabled_buf, "yes") == 0;
 }
+
+/**
+ * Checks if the force link training failure debugfs
+ * is available for a specific output.
+ *
+ * @drmfd: file descriptor of the DRM device.
+ * @output: output to check.
+ * Returns:
+ *  true if the debugfs is available, false otherwise.
+ */
+bool igt_has_force_link_training_failure_debugfs(int drmfd, igt_output_t *output)
+{
+	int debugfs_fd, ret;
+	char buf[512];
+
+	igt_assert_f(output->name, "Invalid output\n");
+	debugfs_fd = igt_debugfs_connector_dir(drmfd, output->name, O_RDONLY);
+	if (debugfs_fd < 0)
+		return false;
+	ret = igt_debugfs_simple_read(debugfs_fd, "i915_dp_force_link_training_failure", buf, sizeof(buf));
+	close(debugfs_fd);
+	return ret >= 0;
+}
diff --git a/lib/igt_kms.h b/lib/igt_kms.h
index 9301df1e2..58dd90b85 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -1268,5 +1268,6 @@ enum dp_link_rate igt_get_dp_max_link_rate(int drm_fd, igt_output_t *output);
 enum dp_lane_count igt_get_dp_max_lane_count(int drm_fd, igt_output_t *output);
 void igt_read_link_training_info(int drm_fd, igt_output_t *output,
 				 struct dp_link_training_info *link_training_info);
+bool igt_has_force_link_training_failure_debugfs(int drmfd, igt_output_t *output);
 
 #endif /* __IGT_KMS_H__ */
-- 
2.43.0