That rule looks good.
Have you put it in a file in
50-udev.rules? Then did you reboot or run
/sbin/udevcontrol reload_rules and then
You can test it like so:
Edit: Here is an example that worked for me. In
KERNEL=="ttyS0", NAME="%k", GROUP="adm", MODE="666", OPTIONS="last_rule"
udevcontrol reload_rules then
udevtrigger --verbose. Result:
crw-rw-rw- 1 root adm 4, 64 Oct 18 16:16 /dev/ttyS0
# udevtest /class/tty/ttyS0
main: looking at device '/class/tty/ttyS0' from subsystem 'tty'
udev_node_add: creating device node '/dev/ttyS0', major = '4', minor = '64', mode = '0666', uid = '0', gid = '4'
Edit2: Also you can run
udevcontrol log_priority=debug to get more info reported via syslog.