xref: /freebsd/share/man/man4/est.4 (revision 724b4bfdf1306e4f2c451b6d146fe0fe0353b2c8)
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26.\" $FreeBSD$
27.\"
28.Dd October 18, 2012
29.Dt EST 4
30.Os
31.Sh NAME
32.Nm est
33.Nd Enhanced Speedstep Technology
34.Sh SYNOPSIS
35To compile this capability into your kernel
36place the following line in your kernel
37configuration file:
38.Bd -ragged -offset indent
39.Cd "device cpufreq"
40.Ed
41.Sh DESCRIPTION
42The
43.Nm
44interface provides support for the Intel Enhanced Speedstep Technology.
45.Pp
46Note that
47.Nm
48capabilities are automatically loaded by the
49.Xr cpufreq 4
50driver.
51.Sh LOADER TUNABLES
52The
53.Nm
54interface is intended to allow
55.Xr cpufreq 4
56to access and implement Intel Enhanced SpeedStep Technology via
57.Xr acpi 4
58and the acpi_perf interface accessors.
59If the default settings are not optimal, the following sysctls can be
60used to modify or monitor
61.Nm
62behavior.
63.Bl -tag -width indent
64.It hw.est.msr_info
65Attempt to infer information from direct probing of the msr.
66Should only be used in diagnostic cases.
67.Pq default 0
68.It hw.est.strict
69Validate frequency requested is accepted by the cpu when set.
70It appears that this will only work on single core cpus.
71.Pq default 0
72.El
73.Sh SYSCTL VARIABLES
74The following
75.Xr sysctl 8
76values are available
77.Bl -tag -width indent
78.It Va dev.est.%d.\%desc
79Description of support, almost always Enhanced SpeedStep Frequency Control.
80.It dev.est.0.%desc: Enhanced SpeedStep Frequency Control
81.It Va dev.est.%d.\%driver
82Driver in use, always est.
83.It dev.est.0.%driver: est
84.It Va dev.est.%d.\%parent
85.It dev.est.0.%parent: cpu0
86The cpu that is exposing these frequencies.
87For example
88.Va cpu0 .
89.It Va dev.est.%d.freq_settings .
90The valid frequencies that are allowed by this CPU and their step values.
91.It dev.est.0.freq_settings: 2201/45000 2200/45000 2000/39581 1900/37387
921800/34806 1700/32703 1600/30227 1500/28212 1400/25828 1300/23900 1200/21613
931100/19775 1000/17582 900/15437 800/13723
94.Pp
95.El
96.Sh DIAGNOSTICS
97.Bl -diag
98.It "est%d: <Enhanced SpeedStep Frequency Control> on cpu%d"
99.Pp
100Indicates normal startup of this interface.
101.It "est: CPU supports Enhanced Speedstep, but is not recognized."
102.It "est: cpu_vendor GenuineIntel, msr 471c471c0600471c"
103.It "device_attach: est%d attach returned 6"
104.Pp
105Indicates all attempts to attach to this interface have failed.
106This usually indicates an improper BIOS setting restricting O/S
107control of the CPU speeds.
108Consult your BIOS documentation for more details.
109.El
110.Sh COMPATIBILITY
111.Nm
112is only found on supported Intel CPUs.
113.Sh SEE ALSO
114.Xr cpufreq 4
115.Rs
116.%T "Intel 64 and IA-32 Architectures Software Developer Manuals"
117.%U "http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html"
118.Re
119.Sh AUTHORS
120This manual page was written by
121.An Sean Bruno Aq sbruno@FreeBSD.org .
122