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33 .Nd Enhanced Speedstep Technology
35 To compile this capability into your kernel
36 place the following line in your kernel
38 .Bd -ragged -offset indent
44 interface provides support for the Intel Enhanced Speedstep Technology.
48 capabilities are automatically loaded by the
54 interface is intended to allow
56 to access and implement Intel Enhanced SpeedStep Technology via
58 and the acpi_perf interface accessors.
59 If the default settings are not optimal, the following sysctls can be
60 used to modify or monitor
63 .Bl -tag -width indent
65 Attempt to infer information from direct probing of the msr.
66 Should only be used in diagnostic cases
69 Validate frequency requested is accepted by the cpu when set.
70 It appears that this will only work on single core cpus.
75 .It "est%d: <Enhanced SpeedStep Frequency Control> on cpu%d"
77 Indicates normal startup of this interface.
78 .It "est: CPU supports Enhanced Speedstep, but is not recognized."
79 .It "est: cpu_vendor GenuineIntel, msr 471c471c0600471c"
80 .It "device_attach: est%d attach returned 6"
82 Indicates all attempts to attach to this interface have failed.
83 This usually indicates an improper BIOS setting restricting O/S
84 control of the CPU speeds.
85 Consult your BIOS documentation for more details.
89 is only found on supported Intel CPUs.
93 .%T "Intel 64 and IA-32 Architectures Software Developer Manuals"
94 .%U "http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html"
97 This manual page was written by
98 .An Sean Bruno Aq sbruno@FreeBSD.org .