NAME
ehci —
USB Enhanced Host Controller
driver
SYNOPSIS
ehci* at cardbus? function ?
ehci* at pci? dev ? function ?
usb* at ehci?
DESCRIPTION
The
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.
SEE ALSO
cardbus(4),
ohci(4),
pci(4),
uhci(4),
usb(4)
HISTORY
The
ehci driver appeared in
NetBSD
1.6.
BUGS
The support for hubs that are connected with high speed upstream and low or full
speed downstream (i.e., for transaction translators) is limited.