diff --git a/pre-upload.py b/pre-upload.py
index 11b51fe..1d2c5b1 100755
--- a/pre-upload.py
+++ b/pre-upload.py
@@ -1098,6 +1098,9 @@
   # information on that file in our source trees, so let's suppress the
   # warning.
   options.append('--ignore=FILE_PATH_CHANGES')
+  # Do not complain about the Change-Id: fields, since we use Gerrit.
+  # Upstream does not want those lines (since they do not use Gerrit), but
+  # we always do, so disable the check globally.
   options.append('--ignore=GERRIT_CHANGE_ID')
   cmd = ['%s/checkpatch.pl' % hooks_dir] + options + ['-']
   cmd_result = cros_build_lib.RunCommand(cmd=cmd,