NAME

       est — Enhanced Speedstep Technology

SYNOPSIS

       To compile this capability into your kernel place the following line in your kernel configuration file:

             device cpufreq

DESCRIPTION

       The est interface provides support for the Intel Enhanced Speedstep Technology.

       Note that est capabilities are automatically loaded by the cpufreq(4) driver.

LOADER TUNABLES

       The  est  interface  is  intended  to  allow  cpufreq(4) to access and implement Intel Enhanced SpeedStep
       Technology via 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 est behavior.

       hw.est.msr_info
               Attempt  to  infer information from direct probing of the msr.  Should only be used in diagnostic
               cases.  (default 0)

       hw.est.strict
               Validate frequency requested is accepted by the CPU when set.  It appears  that  this  will  only
               work on single core cpus.  (default 0)

SYSCTL VARIABLES

       The following sysctl(8) values are available

       dev.est.%d.%desc
               Description of support, almost always Enhanced SpeedStep Frequency Control.

       dev.est.0.%desc: Enhanced SpeedStep Frequency Control

       dev.est.%d.%driver
               Driver in use, always est.

       dev.est.0.%driver: est

       dev.est.%d.%parent
               The CPU that is exposing these frequencies.  For example cpu0.

       dev.est.0.%parent: cpu0

       dev.est.%d.freq_settings.
               The valid frequencies that are allowed by this CPU and their step values.

       dev.est.0.freq_settings: 2201/45000 2200/45000 2000/39581 1900/37387
               1800/34806   1700/32703   1600/30227   1500/28212  1400/25828  1300/23900  1200/21613  1100/19775
               1000/17582 900/15437 800/13723

DIAGNOSTICS

       est%d: <Enhanced SpeedStep Frequency Control> on cpu%d

       Indicates normal startup of this interface.

       est: CPU supports Enhanced Speedstep, but is not recognized.
       est: cpu_vendor GenuineIntel, msr 471c471c0600471c
       device_attach: est%d attach returned 6

       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.

COMPATIBILITY

       est is only found on supported Intel CPUs.

SEE ALSO

       cpufreq(4)

       Intel        64        and        IA-32       Architectures       Software       Developer       Manuals,
       http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html.

AUTHORS

       This manual page was written by Sean Bruno <sbruno@FreeBSD.org>.

Debian                                           April 21, 2020                                           EST(4)