Quirky WOL Behavior
For a long time I have noticed a quirk with the Wake-On-LAN (WOL) feature.
If the network port is connected to a live switch or router, then the system remembers the WOL option. If the switch or router is unavailable, basically the same as disconnecting the cable, the machine will not thereafter awaken with a WOL magic packet.
The machine always has 5V standby power available and awakens itself when using the real time clock.
The particular machine I tested uses an Asus M3N78-EM motherboard and onboard NIC using the Nvidia GeForce 8300 MCP78S controller. I have Slackware 12.2 installed, using the 2.6.30.10 kernel and the forcedeth driver.
I have tried various scenarios and shutdown settings. I have tried setting WOL (usr/sbin/ethtool -s eth0 wol g) before and after shutting down the network interface. Makes no difference. The behavior is repeatable. The only criterion that matters is whether the NIC is connected to something "live."
Is this behavior caused by the kernel, driver, BIOS, or controller?
Thanks again.
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