.\" $NetBSD: powernow.4,v 1.3 2017/02/17 22:10:47 christos Exp $
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.\" Copyright (c) 2011 Jukka Ruohonen <jruohonen@iki.fi>
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.Dd February 17, 2017
.Dt POWERNOW 4
.Os
.Sh NAME
.Nm powernow
.Nd AMD PowerNow! and Cool'n'Quiet
.Sh SYNOPSIS
.Cd "powernow0 at cpu0"
.Sh DESCRIPTION
The
.Nm
driver supports
.Tn AMD
.Dq PowerNow!
and
.Dq Cool'n'Quiet
.Tn CPU
frequency scaling technologies.
The following
.Xr sysctl 8
variables are available with
.Nm :
.Bl -tag -width "machdep.powernow.frequency.available" -offset 2n
.It Ic machdep.powernow.frequency.target
The target frequency of the
.Tn CPUs .
.It Ic machdep.powernow.frequency.current
The current frequency.
.It Ic machdep.powernow.frequency.available
The available frequencies.
.El
.Pp
Note, however, that these variables are
not guaranteed to exist in the future versions of
.Nx .
.Sh SEE ALSO
.Xr acpicpu 4 ,
.Xr x86/est 4 ,
.Xr x86/odcm 4
.Sh CAVEATS
The
.Nm
driver is considered a legacy interface to
be used only with relatively old systems.
The driver supports only
.Tn AMD
processor families
.Tn K7
(for instance, Duron, Athlon, and some Semprons) and
.Tn K8
(namely, the early 64-bit family, including Athlon 64, Opteron, and Turion).