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.\" $FreeBSD: releng/12.2/share/man/man4/xhci.4 332950 2018-04-24 17:46:33Z trasz $
.\"
.Dd April 24, 2018
.Dt XHCI 4
.Os
.Sh NAME
.Nm xhci
.Nd USB eXtensible Host Controller driver
.Sh SYNOPSIS
.Cd "device xhci"
.Sh DESCRIPTION
The
.Nm
driver provides support for the
.Tn USB
eXtensible Host Controller Interface,
which allows use of
.Tn USB
1.0, 2.0 and 3.0 devices on the same
.Tn USB
port.
.Pp
The
.Tn XHCI
controller supports
.Tn USB
connection speeds up to 5.0Gbps when using a USB 3.0 compliant device.
.Sh HARDWARE
The
.Nm
driver supports
.Tn XHCI
compatible controllers having PCI class 12 (serial bus),
subclass 3 (USB) and programming interface 48 (XHCI).
.Sh SYSCTL VARIABLES
The following variables are available as both
.Xr sysctl 8
variables and
.Xr loader 8
tunables:
.Bl -tag -width indent
.It Va hw.usb.xhci.debug
Debug output level, where 0 is debugging disabled and larger values increase
debug message verbosity.
Default is 0.
.Sh SEE ALSO
.Xr ehci 4 ,
.Xr ohci 4 ,
.Xr uhci 4 ,
.Xr usb 4
.Sh HISTORY
The
.Nm
device driver first appeared in
.Fx 8.2 .