title: Cannot disable systemd serial-getty service
body: <p>On Raspberry Pi with Arch Linux there is a service active called <code>serial-getty@AMA0</code>.</p>
  
  <p>The unit file is: /usr/lib/systemd/system/serial-getty@.service</p>
  
  <p>As root I can invoke</p>
  
  <pre><code>systemctl stop serial-getty@ttyAMA0
  systemctl disable serial-getty@ttyAMA0
  </code></pre>
  
  <p>But after reboot the service is enabled and running again.</p>
  
  <p>Why is the service enabled after disabling it? How can I disable it permanent?</p>
  
  <p>UPDATE</p>
  
  <p>systemd uses <a href="http://www.freedesktop.org/wiki/Software/systemd/Generators/" rel="noreferrer">generators</a> at /usr/lib/systemd/system-generators/ is a binary called systemd-getty-generator. This binary runs at system start and adds the symlink serial-getty@ttyAMA0.service to <code>/run/systemd/generator/getty.target.wants</code>.</p>
  
  <p>I eventually found a dirty solution. I commented out all actions in /usr/lib/systemd/system/serial-getty@.service. The service did appear to start anyway, but without blocking ttyAMA0.</p>