I have a Lenovo X61. I got the same problem. One gpe had hundreds of interrupts (#12 in my case).
However, disabling gpe12 did not help, CPU spikes continued. `ifconfig eth0 down` did stop the kworker CPU spikes. I disabled allow-hotplug for eth0 in /etc/network/interfaces. Now it is fine, with gpe12 enabled again. I'm glad I got a wireless router recently. :-) HTH. -Mark
