igt/pm_rpm: Use libc 'ftw' rather than opencoding our own filetree walk

By using ftw, we avoid the issue of having to handle directory recursion
ourselves and can focus on the test of checking the reading a
sysfs/debugfs does not break runtime suspend. In the process, disregard
errors when opening the individual files as they may fail for other
reasons.

v2: Bracket the file open/close with the wait_for_suspended() tests.
Whilst the fd is open, it may be keeping the device awake, e.g.
i915_forcewake_user.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Jari Tahvanainen <jari.tahvanainen@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/igt_debugfs.h b/lib/igt_debugfs.h
index f1a76406..4fa49d21 100644
--- a/lib/igt_debugfs.h
+++ b/lib/igt_debugfs.h
@@ -32,6 +32,7 @@
 enum pipe;
 
 const char *igt_debugfs_mount(void);
+char *igt_debugfs_path(int device, char *path, int pathlen);
 
 int igt_debugfs_dir(int device);