[PATCH i-g-t v1] lib/igt_debugfs: Add "errno" to debug print

[Ngai-Mint Kwan <ngai-mint.kwan@linux.intel.com>]

When igt_debugfs_path() fails under igt_debugfs_dir(), add "errno" to the
debug print for additional context of the failure.

Signed-off-by: Ngai-Mint Kwan <ngai-mint.kwan@linux.intel.com>
---
 lib/igt_debugfs.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/igt_debugfs.c b/lib/igt_debugfs.c
index ed0a20773..a8c45945c 100644
--- a/lib/igt_debugfs.c
+++ b/lib/igt_debugfs.c
@@ -187,8 +187,12 @@ int igt_debugfs_dir(int device)
 	int debugfs_dir_fd;
 	char path[200];
 
-	if (igt_debug_on(!igt_debugfs_path(device, path, sizeof(path))))
+	errno = 0;
+	if (igt_debug_on(!igt_debugfs_path(device, path, sizeof(path)))) {
+		igt_debug("Last errno: %i, %s\n", errno, strerror(errno));
+
 		return -1;
+	}
 
 	debugfs_dir_fd = open(path, O_RDONLY);
 	igt_debug_on_f(debugfs_dir_fd < 0, "path: %s\n", path);
-- 
2.43.0