ACPI disables USB ports on Lenovo X200

[Damian Gerow]

Damian Gerow wrote:
: : Hi Damian,
: :     Have you also tried setting hw.usb.debug=1 and see what's reported
: : by the new USB stack?
: 
: Yup.  I couldn't remember if hw.usb.debug was a blanket statement for
: hw.usb*debug, so I also set hw.usb.ehci.debug, hw.usb.ohci.debug,
: hw.usb.dev.debug, and hw.usb.ums.debug to 1.

For kicks, I just booted a kernel without any USB support at all, and
experience the same symptoms: the mouse is functional (well, appears to be,
anyhow) when the boot loader is active, but goes dark around when ACPI
starts to do its thing.