Copyright (c) 2011 Jukka Ruohonen <jruohonen@iki.fi>
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.Dd September 7, 2020 .Dt EST 4 x86 .Os .Sh NAME .Nm est .Nd Enhanced SpeedStep .Sh SYNOPSIS .Cd "est0 at cpu0" .Sh DESCRIPTION The .Nm driver provides support for Enhanced SpeedStep introduced in Intel's first and second generation of Pentium M processors. The following .Xr sysctl 8 variables are available with .Nm : l -tag -width "machdep.cpu.frequency.available" -offset indent t Ic machdep.cpu.frequency.target The target frequency of the .Tn CPUs . t Ic machdep.cpu.frequency.current The current frequency. t Ic machdep.cpu.frequency.available The frequencies recognized by .Nm . .El
p Note, however, that these variables are not guaranteed to exist in the future versions of .Nx . .Sh SEE ALSO .Xr acpicpu 4 , .Xr x86/odcm 4 , .Xr x86/powernow 4 .Rs .%A Intel Corporation .%T Intel Pentium M Processor. .%T Datasheet .%D March, 2004 .%U http://download.intel.com/support/processors/mobile/pm/sb/25261203.pdf .Re .Rs .%A Intel Corporation .%T Enhanced Intel SpeedStep Technology for the Intel Pentium M Processor. .%T White Paper .%D March, 2004 .%U http://download.intel.com/design/network/papers/30117401.pdf .Re .Sh CAVEATS The .Nm driver is considered a legacy interface to be used only with old systems. It is known to be problematic with new .Tn CPUs . Furthermore, in the unlikely case where both .Nm and .Xr x86/ichlpcib 4 or .Xr piixpcib 4 provide support for SpeedStep, the PCI-based interfaces should not be accessed due possible race conditions.