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.\" Copyright (c) 2012 Sean Bruno <sbruno@freebsd.org>
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.Dd June 12, 2012
.Dt EST 4
.Os
.Sh NAME
.Nm est
.Nd Enhanced Speedstep Technology
.Sh SYNOPSIS
To compile this capability into your kernel
place the following line in your kernel
configuration file:
.Bd -ragged -offset indent
.Cd "device cpufreq"
.Ed
.Sh DESCRIPTION
The
.Nm
interface provides support for the Intel Enhanced Speedstep Technology.
.Pp
Note that
.Nm
capabilities are automatically loaded by the
.Xr cpufreq 4
driver.
.Sh LOADER TUNABLES
The
.Nm
interface is intended to allow
.Xr cpufreq 4
to access and implement Intel Enhanced SpeedStep Technology via
.Xr acpi 4
and the acpi_perf interface accessors.
If the default settings are not optimal, the following sysctls can be
used to modify or monitor
.Nm
behavior.
.Bl -tag -width indent
.It hw.est.msr_info
Attempt to infer information from direct probing of the msr.
Should only be used in diagnostic cases 
.Pq default 0
.It hw.est.strict
Do not allow different cpus to be set to different frequencies.
It appears that this will only work on i386 systems 
.Pq default 0
.El
.Sh DIAGNOSTICS
.Bl -diag
.It "est%d: <Enhanced SpeedStep Frequency Control> on cpu%d"
.Pp
Indicates normal startup of this interface.
.It "est: CPU supports Enhanced Speedstep, but is not recognized."
.It "est: cpu_vendor GenuineIntel, msr 471c471c0600471c"
.It "device_attach: est%d attach returned 6"
.Pp
Indicates all attempts to attach to this interface have failed.
This usually indicates an improper BIOS setting restricting O/S
control of the CPU speeds.
Consult your BIOS documentation for more details.
.El
.Sh COMPATIBILITY
.Nm
is only found on supported Intel CPUs.
.Sh SEE ALSO
.Xr cpufreq 4
.Sh SUPPORT
For general information and support,
go to the Intel 64 and IA-32 Architectures Software Developer
Manuals site.
.Pa http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html
.Sh AUTHORS
.Pp
This manual page was written by
.An Sean Bruno Aq sbruno@FreeBSD.org .