Some time ago I noticed that I could no longer boot a remote machine via Wake-on-LAN. This annoyed me quite a bit, as the machine was 2100km away and there was nobody at that location who could boot it for me. I really had no clue why it stopped working. So when I recently arrived at the location again, I started looking into it. Everything I had previously configured was still in place. The BIOS option Power On by PCIE devices was enabled, and I still had this in /etc/local.d/wol.start:
#!/bin/sh
ethtool -s eth0 wol g
echo "GBE" > /proc/acpi/wakeup
Yet, when I ran ethtool eth0, it showed that WOL was disabled:
Settings for eth0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Speed: 1000Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
MDI-X: on (auto)
Supports Wake-on: pumbg
<strong>Wake-on: b</strong>
Current message level: 0x00000007 (7)
drv probe link
Link detected: yes
I manually ran ethtool -s eth0 wol g and verified, now it was enabled:
Settings for eth0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Speed: 1000Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
MDI-X: on (auto)
Supports Wake-on: pumbg
<strong>Wake-on: g</strong>
Current message level: 0x00000007 (7)
drv probe link
Link detected: yes
Then I verified in /proc/acpi/wakeup if the PCIe device was allowed to wake the system:
taz ~ # cat /proc/acpi/wakeup
Device S-state Status Sysfs node
UAR1 S4 *disabled pnp:00:05
PS2K S4 *disabled
PS2M S4 *disabled
BR20 S3 *disabled pci:0000:00:1e.0
EUSB S4 *enabled pci:0000:00:1d.0
USBE S4 *enabled pci:0000:00:1a.0
NPE1 S4 *disabled pci:0000:00:01.0
NPE3 S4 *disabled pci:0000:00:02.0
NPE4 S4 *disabled
NPE5 S4 *disabled
NPE6 S4 *disabled
NPE7 S4 *disabled pci:0000:00:03.0
NPE8 S4 *disabled
NPE9 S4 *disabled
NPEA S4 *disabled
PEX0 S4 *disabled pci:0000:00:1c.0
PEX1 S4 *disabled pci:0000:00:1c.1
PEX2 S4 *disabled pci:0000:00:1c.2
PEX3 S4 *disabled
PEX4 S4 *disabled pci:0000:00:1c.4
PEX5 S4 *disabled pci:0000:00:1c.5
PEX6 S4 *disabled
PEX7 S4 *disabled pci:0000:00:1c.7
<strong>GBE S4 *enabled pci:0000:00:19.0</strong>
NPE2 S4 *disabled pci:0000:00:01.1
SLPB S0 *disabled
PWRB S4 *enabled platform:PNP0C0C:00
All good, so I shut down the machine and tried to wake it via a Wake-on-LAN magic packet, by running this on my OpenWrt router: etherwake -i br-lan 10:bf:48:d5:44:b8. The machine booted, and I was happy. But then I ran ethtool again, and noticed Wake-on-LAN was again disabled. I verified that the startup script was actually executed by inserting an echo to a file in it and rebooting again. This confirmed that the startup script was working. So there must be something that toggles the WOL state after the startup script has been executed. Suspect number 1: NetworkManager. Started searching the web and quickly found an explanation. As you can read in the NetworkManager 1.0.6 release announcement, it now supports configuring Wake-on-LAN capabilities of Ethernet hardware. So I checked if I had recently updated NetworkManager, and according to qlop -gHv networkmanager that was indeed the case:
networkmanager-1.0.6: Tue Oct 13 05:23:19 2015: 1 minute, 53 seconds
Then I checked the Wake-on-LAN setting for my connection with nmcli c show 713b0ecf-fc5e-4387-99bd-4dceedd0027b | grep wake-on-lan:
802-3-ethernet.wake-on-lan: default
802-3-ethernet.wake-on-lan-password: --
Changed it to magic with nmcli c modify 713b0ecf-fc5e-4387-99bd-4dceedd0027b 802-3-ethernet.wake-on-lan magic and verified with ethtool. It still showed as disabled, so I disconnected and reconnected the connection via plasma-nm, verified again with ethtool and now WOL was enabled. Shutdown, etherwake, check WOL state in ethtool, all good. Yay.