NAME
est —
Enhanced SpeedStep
SYNOPSIS
est0 at cpu0
DESCRIPTION
The
est driver provides support for Enhanced SpeedStep
introduced in Intel's first and second generation of Pentium M processors. The
following
sysctl(8) variables
are available with
est:
-
-
- machdep.est.frequency.target
- The target frequency of the CPUs.
-
-
- machdep.est.frequency.current
- The current frequency.
-
-
- machdep.est.frequency.available
- The frequencies recognized by est.
Note, however, that these variables are not guaranteed to exist in the future
versions of
NetBSD.
SEE ALSO
acpicpu(4),
x86/odcm(4),
x86/powernow(4)
Intel Corporation,
Intel Pentium M Processor.,
Datasheet,
http://download.intel.com/support/processors/mobile/pm/sb/25261203.pdf,
March, 2004.
Intel Corporation,
Enhanced Intel SpeedStep Technology for the Intel Pentium M
Processor., White Paper,
http://download.intel.com/design/network/papers/30117401.pdf,
March, 2004.
CAVEATS
The
est driver is considered a legacy interface to be used
only with old systems. It is known to be problematic with new CPUs.
Furthermore, in the unlikely case where both
est and
x86/ichlpcib(4) or
piixpcib(4) provide support
for SpeedStep, the PCI-based interfaces should not be accessed due possible
race conditions.