I forgot this patch that will avoid people to wonder why nothing happens when sys dev is wrong: --- tmp/v4l-utils-1.20.0/utils/keytable/keytable.c 2020-05-21 11:22:36.000000000 +0100 +++ v4l-utils-1.20.0/utils/keytable/keytable.c 2023-10-29 20:23:48.580655881 +0000 @@ -2067,6 +2067,7 @@ return -1; rc_dev.sysfs_name = names->name; if (get_attribs(&rc_dev, names->name)) { + fprintf(stderr, _("Wrong sysdev %s: cannot retrieve attributes\n"), devclass); free_names(names); return -1; } Regards