1.\" $NetBSD: ehci.4,v 1.8 2001/11/21 17:22:56 augustss Exp $ 2.\" 3.\" Copyright (c) 2001 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Lennart Augustsson. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28.\" POSSIBILITY OF SUCH DAMAGE. 29.\" 30.Dd April 24, 2018 31.Dt EHCI 4 32.Os 33.Sh NAME 34.Nm ehci 35.Nd USB Enhanced Host Controller driver 36.Sh SYNOPSIS 37.Cd "device ehci" 38.Sh DESCRIPTION 39The 40.Nm 41driver provides support for the 42.Tn USB 43Enhanced Host Controller Interface, 44which is used by 45.Tn USB 462.0 controllers. 47.Pp 48.Tn EHCI 49controllers are peculiar in that they can only handle the 50.Tn USB 512.0 protocol. 52This means that they normally have one or more companion controllers 53(i.e., 54.Xr ohci 4 55or 56.Xr uhci 4 ) 57handling USB 1.x devices. 58Consequently each 59.Tn USB 60connector is electrically connected to two 61.Tn USB 62controllers. 63The handling of this is totally automatic, 64but can be noticed since 65.Tn USB 661.x and 67.Tn USB 682.0 devices plugged in to the same 69connector appear to connect to different USB buses. 70.Sh LOADER TUNABLES 71When the kernel has been compiled with 72.Cd options USB_DEBUG , 73some tunables become available that affect the behavior of 74.Nm . 75These tunables can be set at the 76.Xr loader 8 77prompt before booting the kernel or stored in 78.Xr loader.conf 5 . 79.Bl -tag -width "xxxxxx" 80.It Va hw.usb.ehci.lostintrbug 81This tunable enables the lost interrupt quirk. 82The default value is 0 (off). 83.It Va hw.usb.ehci.iaadbug 84This tunable enables the EHCI doorbell quirk. 85The default value is 0 (off). 86.It Va hw.usb.ehci.no_hs 87This tunable disables USB devices to attach like HIGH-speed ones and will force all attached devices to attach to the FULL- or LOW-speed companion controller. 88The default value is 0 (off). 89.El 90.Sh SYSCTL VARIABLES 91The following variables are available as both 92.Xr sysctl 8 93variables and 94.Xr loader 8 95tunables: 96.Bl -tag -width indent 97.It Va hw.usb.ehci.debug 98Debug output level, where 0 is debugging disabled and larger values increase 99debug message verbosity. 100Default is 0. 101.El 102.Sh SEE ALSO 103.Xr ohci 4 , 104.Xr uhci 4 , 105.Xr usb 4 , 106.Xr xhci 4 107.Sh HISTORY 108The 109.Nm 110device driver first appeared in 111.Fx 5.1 . 112