A mkinitcpio hook to fix e1000e network driver issues with WoL packets on startup

info.md

The X230 I use for playing with Coreboot has a Intel Corporation 82579LM ethernet card with WoL support. Problem is, when the laptop is woken up via a WoL packet, the e1000e driver in linux is not able to bring up the network card correctly.

As highlighted on this Arch forums post, the problem can be solved resetting the PCI device before the driver is loaded. This mkinitcpio hook does exactly that if you add reset-e1000e as the first hook in your HOOKS list. Don't forget to rebuild your initrd.

install_hook_reset-e1000e

#!/bin/bash
# Place this file in /etc/initcpio/install/reset-e1000e

build ()
{
  add_runscript
}

help ()
{
    cat<<HELPEOF
This hook reset the 82579LM Ethernet board on my Thinkpad X230 laptop on
boot to restore it to a clean state after a WoL packet woke up the PC.
HELPEOF
}

runtime_hook_reset-e1000e

#!/usr/bin/ash
# Place this file in /etc/initcpio/hooks/reset-e1000e

run_hook ()
{
  echo "Resetting PCI Ethernet card"
  # Hardcoded PCI path, check the right one on your machine
  echo 1 > /sys/devices/pci0000\:00/0000\:00\:19.0/reset
}