Command: idlehalt
IDLEHALT activates built-in kernel energy saving functionality if
n is not 0.
IDLEHALT is a CONFIG.SYS / FDCONFIG.SYS command.
Syntax:
idlehalt=n
where n can be -1, 0, 1 or higher (default 0)
Options:
- none -
Comments:
IDLEHALT activates built-in kernel energy saving functionality if
n is not 0. Value -1 enables all hooks, 1 enables only "safe" hooks,
CPU halted only if kernel is waiting for CON char device input.
Further hooks for n=-1 and n>0 depend on the kernel version:
In addition to the safe hooks, other hooks can get activated, for
example one for int 0x2f, ax=0x1680 "release time slice".
Note: In rare cases, entering or leaving HLT mode (which causes big
changes in CPU power consumption) can cause crashes if cheap power
supplies or mainboards cannot properly filter the transients.
Underclocking the whole system may help.
Linux always does a few HLT at boot time, to force a hang on buggy
systems early (boot with no-hlt to disable HLT).
P90 may have buggy HLT? www.tavi.co.uk/ps2pages/ohland/halt.html
IDLEHALT is a command internal to kernel.sys and needs no other
file in order to work.
Examples:
IN CONFIG.SYS / FDCONFIG.SYS:
idlehalt=1
See also:
config.sys/fdconfig.sys
Copyright © 2003 Robert Platt, updated 2008 by W. Spiegl.
This file is derived from the FreeDOS Spec Command HOWTO.
See the file H2Cpying for copying conditions.