If you are using a new T61 or T61p please check your bios version. You can do this using:
lshal | grep system.firmware.version
If you are not running 7LETB7WW, then you really need to update your BIOS to v2.17-1.08
Symptoms of an old BIOS version are hard hangs when docking/undocking from the smart dock, or the USB might mysteriously stop working with Disabling IRQ #19 in the logs.
