53e8f6c919
Remarks:
1. All processors (x86 or not) for which the vendor has implemented
ACPI I/O access routines are supported. Native instructions are
currently supported only for Intel's "Enhanced Speedstep". Code for
"PowerNow!" (AMD) will be merged later. Native support for VIA's
"PowerSaver" will be investigated.
2. Backwards compatibility with existing userland code is maintained.
Comparable to the case with cpu_idle(9), the ACPI CPU driver
installs alternative functions for the existing sysctl(8) controls.
The "native" behavior (if any) is restored upon detachment.
3. The dynamic nature of ACPI-provided P-states needs more investigation.
The maximum frequency induced (but not forced) by the firmware may
change dynamically. Currently, the sysctl(8) controls error out with
a value larger than the dynamic maximum. The code itself does not
however yet react to the notifications from the firmware by changing
the frequencies in-place. Presumably the system administrator should
be able to choose whether to use dynamic or static frequencies.
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|---|---|---|
| .. | ||
| acpi | ||
| conf | ||
| include | ||
| isa | ||
| pci | ||
| x86 | ||