68 lines
1.9 KiB
Groff
68 lines
1.9 KiB
Groff
.\" $NetBSD: piixpcib.4,v 1.5 2011/03/01 19:41:05 jruoho Exp $
|
|
.\"
|
|
.\" Copyright (c) 2007 Stephan Meisinger
|
|
.\"
|
|
.\" Permission to use, copy, modify, and distribute this software for any
|
|
.\" purpose with or without fee is hereby granted, provided that the above
|
|
.\" copyright notice and this permission notice appear in all copies.
|
|
.\"
|
|
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
|
|
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
|
|
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
|
|
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
|
|
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
|
|
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
|
|
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
|
.\"
|
|
.Dd March 1, 2011
|
|
.Dt PIIXPCIB 4
|
|
.Os
|
|
.Sh NAME
|
|
.Nm piixpcib
|
|
.Nd Intel PIIX4 PCI-ISA bridge with SpeedStep
|
|
.Sh SYNOPSIS
|
|
.Cd "piixpcib* at pci? dev ? function ?"
|
|
.Cd "isa* at piixpcib?"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
driver provides support for the Intel PIIX and compatible PCI-ISA Bridges
|
|
with Intel's first generation SpeedStep.
|
|
.Pp
|
|
Frequency scaling is supported on Pentium III with two voltage modes,
|
|
used by SpeedStep as power states low and high.
|
|
The driver will switch into low power state by reducing voltage
|
|
and frequency of the CPU.
|
|
The factor depends on the processor itself, but
|
|
will always reduce power consumption about 1/2.
|
|
.Pp
|
|
The user can manually control the CPU frequency with the
|
|
.Xr sysctl 8
|
|
program using the following node:
|
|
.Bl -tag -width usscanner -offset indent
|
|
.It machdep.speedstep_state = [0/1]
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr est 4 ,
|
|
.Xr isa 4 ,
|
|
.Xr pci 4 ,
|
|
.Xr apmd 8 ,
|
|
.Xr sysctl 8
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
driver first appeared in
|
|
.Fx 5.5
|
|
and then in
|
|
.Nx 4.0 .
|
|
.Sh AUTHORS
|
|
.An -nosplit
|
|
The current
|
|
.Nm
|
|
driver was written by
|
|
.An Bruno Ducrot .
|
|
It was ported to
|
|
.Nx
|
|
by
|
|
.An Jared D. McNeill Aq jmcneill@NetBSD.org .
|