Error opening low/full speed isoc endpoint.
A low/full speed device is attached to a USB2 hub, and
transaction translations are not yet supported.
Reattach the device to the root hub instead.
It annoyed me that this doesn't yet work. But since I needed to plug my
device into the hub, I found a different solution: Just disable ehci
support in kernel. Works fine :-D keyboard, mouse and full-duplex audio
all at one hub.
Reading the TODO in ehci.c suggests that fixing this the right way would
be a lot of work - writing a scheduler... ?