Three Monkeys, Three Typewriters, Two Days

November 19, 2009

Linux (FC12) wake-on-LAN woes

I just spent the last two hours or so trying to get wake-on-lan to actually work on Linux. Sadly, most of the HOWTOs (assuming the link isn't broken) aren't actually that useful. Here's what I can observe

  1. Wake-on-LAN is enabled in the BIOS.
  2. Shutting down with "poweroff" or "shutdown -h" leaves the network card powered (the link light is on).
  3. Sending a magic packet to the machine doesn't power it on.
  4. If I hit the small black button on the back of the power supply once, it makes a slight noise, and after that sending a magic packet does power on the machine.

So my best guess so far is that poweroff puts the power supply into a state from which the NIC can't wake it up. I have no idea what that state might be, nor how to change this behavior. I welcome any ideas!

Update: To be clear, I've tried all the power management setting combinations in the BIOS. Most have the behavior I describe above; the rest power down the network card as well.

Update: To forestall more comments from people who aren't reading item 4 above carefully, the network card itself reports that it'll do wake on magic packet when you ask with ethtool. It DOES do wake on magic packet, in fact, but only after I press that button on the power supply. And honestly, try to give me some credit for actually trying the one thing all the howtos on this have in common, that being ethtool.

Posted by bzbarsky at November 19, 2009 12:02 AM