Hi,
I'm using the new Lenovo T420 port on gerrit[1] and found a bug about USB(in my post on the gerrit page). And just now I found a work around on this issue.
First I tested a USB disk on the buggy USB port before suspending the system, it works fine. Then I unplugged the USB disk, suspended my system, resume, and replugged the disk, the bug occurred. Then I unplugged the disk, reload the ehci_pci module as follows:
rmmod ehci_pci modprobe ehci-pci
The I plugged in the USB disk, it worked fine again.
I think the kernel message[2] gives some information about it, because it gives two different port number on the USB device. But I know almost nothing about USB, so I'm not sure what's happening.
[1] http://review.coreboot.org/#/c/11765/ [2] see the attached dmesg.log
Iru Cai