I've just purchased a cheap Turbo-Trak USB keyboard, but when I connect it
up (to various ports on different machines running 1.6.1/i386) it reports:

uhub0: port 1, set config at addr 2 failed
uhub0: device problem, disabling port 1

Switching on USB_DEBUG shows:

usbd_transfer_cb: short transfer 1<9
uhub_explore: usb_new_device failed, error=SHORT_XFER

Serves me right buying cheap rubbish, but (as expected) it works with
Windows.

Just tried it on -current/i386 and it shows the same (except doesn't seem
to print the "set config" line.

-- 
Stephen