NetBSD/share/man/man4/ehci.4

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.\" $NetBSD: ehci.4,v 1.16 2008/08/10 13:39:58 jmcneill Exp $
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.\" by Lennart Augustsson.
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.Dd Aug 10, 2008
.Dt EHCI 4
.Os
.Sh NAME
.Nm ehci
.Nd USB Enhanced Host Controller driver
.Sh SYNOPSIS
.Cd "ehci* at cardbus? function ?"
.Cd "ehci* at pci? dev ? function ?"
.Cd "usb* at ehci?"
.Sh DESCRIPTION
The
.Nm
driver provides support for the USB Enhanced Host Controller Interface,
which is used by USB 2.0 controllers.
.Pp
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.,
.Xr ohci 4
or
.Xr 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.
.Sh SEE ALSO
.Xr cardbus 4 ,
.Xr ohci 4 ,
.Xr pci 4 ,
.Xr uhci 4 ,
.Xr usb 4
.Sh HISTORY
The
.Nm
driver appeared in
.Nx 1.6 .
.Sh 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.