[arch-general] Ethernet stopped working after update

[dmbuce at gmail.com]

My card:

# lspci | grep -i ethernet
Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI 
Express Gigabit Ethernet controller (rev 03)

After doing pacman -Syu, ethernet on my desktop stopped working. The 
card on my laptop is the same, at least according to lspci, and is 
working fine.

When I upgraded, there was a change in syntax in rc.conf for defining 
the network, but I'm just attempting dhcp for now before I try to set up 
a static ip:

interface=eth0
address=
netmask=
gateway=


I've tried resetting the router and switching from the kernel's r8169 
driver to the r8168 driver from the aur. I compiled the aur driver on my 
laptop and transferred to the desktop on usb -- as long as they're both 
x86_64, this shouldn't be a problem, right?

Regardless of my choice of driver, ethernet on the laptop works fine, 
and doesn't work at all on the desktop. If I set up ethernet manually 
using ifconfig to define the address/netmask/broadcast/etc (making sure 
the routes are correct), everything appears to work fine until I try to 
ping the router and get "Destination Host Unreachable".

And the kicker is that the light on the router for the port I have my 
ethernet cable plugged into will light up for the laptop, but not the 
desktop. Given this and the other behavior, I'm inclined to think it's a 
hardware issue, but this hardware is only several months old, and having 
this happen right after an upgrade seems unlikely to be a coincidence. 
Anything else I can try short of reinstalling or getting a replacement 
from the manufacturer?