Grepping syslog for tty's, this was the only one to come up on my machine
$ sudo zgrep -a tty /var/log/syslog.*
...
Jun 26 08:25:53 taro kernel: [ 1.786819] 0000:00:16.3: ttyS4 at I/O 0x30a0 (irq = 19, base_baud = 115200) is a 16550A
...
Finding the device from udevadm
$ udevadm info -a /dev/ttyS4
...
ATTRS{device}=="0xa363"
...
Udev persisent rules, to ensure this device will always be /dev/ttySOL
# /etc/udev/rules.d/z25_persistent-serial.rules
KERNEL!="ttyS[0-9]", GOTO="no_serial"
ATTRS{vendor}!="0x8086", GOTO="vendor_not_intel"
# From udevadm
ATTRS{device}=="0xa363", SYMLINK+="ttySOL", ENV{COMMENT}="Serial-Over-Lan $attr{vendor}:$attr{device}"
GOTO="vendor_not_intel"
LABEL="no_serial"
Make udev do it's thing without a reboot
sudo udevadm control --reload
sudo udevadm trigger
Shoud now have a symlink to our tty
$ ls -lah /dev/ttySOL
lrwxrwxrwx 1 root root 5 Jul 1 20:58 /dev/ttySOL -> ttyS4
I didn't do any GRUB stuff but probably should, but for testing, starting getty on my new tty a login showed up in Serial over Lan
systemctl start [email protected]