I had a weird issue where the CPU frequency of my Thinkpad X61 was stuck
To enable the Wake On Lan feature of my Thinkpad X61 that serves as a low power home server I had to jump through some hoops:
1. Enable Wake On Lan (wol) in the machine BIOS. Also make sure that the boot order of the Network boot is set correctly.
2. Disable Cloud Init by removing the config file '50-cloud-init.yaml' from '/etc/netplan' and creating the file could-init.disable by running
sudo touch /etc/cloud/cloud-init.disabled
3. Configure Netplan to enable wol for the network interfaces with a config file '01-netcfg.yaml' in '/etc/netplan' with the contents:
network: ethernets: enp0s25: match: macaddress: 00:1d:72:90:b2:17 dhcp4: true wakeonlan: true version: 2 renderer: networkd
You need to replace the device name and mac address with yours, obviously.
4. I have also added the following line to the crontab with 'crontab -e'
@reboot /usr/sbin/netplan apply
4. To disable the auto sleep when the lid is closed I have edited the file '/etc/systemd/logind.conf' and added the entries: