USB Enhanced Host Controller driver
ehci* at cardbus? function ?
ehci* at pci? dev ? function ?
usb* at ehci?
ehci driver provides support for the USB Enhanced
Host Controller Interface, which is used by USB 2.0 controllers.
EHCI controllers are peculiar in that they can only handle the USB
2.0 protocol. This means that they normally have one or more companion
controllers (i.e., ohci(4) or
uhci(4)) handling USB 1.x
devices. Consequently each USB connector is electrically connected to two
USB controllers. The handling of this is totally automatic, but can be
noticed since USB 1.x and USB 2.0 devices plugged in to the same connector
appear to connect to different USB busses.
ehci driver appeared in NetBSD
The support for hubs that are connected with high speed upstream and low or full
speed downstream (i.e., for transaction translators) is limited.