Datasheet

“main” (Installation and Administration) — 2004/6/25 — 13:29 — page 365 — #391
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17
Power Management
/proc/acpi/thermal_zone/ A separate subdirectory exists for every
thermal zone. A thermal zone is an area with similar thermal prop-
erties whose number and names are designated by the hardware
manufacturer. However, many of the possibilities offered by ACPI
are rarely implemented. Instead, the temperature control is handled
conventionally by the BIOS. The operating system is not given much
opportunity to intervene, as the life span of the hardware is at stake.
Therefore, some of the following descriptions only have a theoretical
value.
/proc/acpi/thermal_zone/*/temperature
Current temperature of the thermal zone.
/proc/acpi/thermal_zone/*/state
The state indicates if everything is “ok” or if ACPI applies “active” or
“passive” cooling. In the case of ACPI-independent fan control, this
state will always be “ok”.
/proc/acpi/thermal_zone/*/cooling_mode
Enables the selection of the passive (less performance, very econom-
ical) or active (full performance, uninterrupted fan noise) cooling
method for full ACPI control.
/proc/acpi/thermal_zone/*/trip_points
Enables the determination of temperature limits for triggering spe-
cific actions like passive or active cooling, suspension (“hot”), or a
shutdown (“critical”).
/proc/acpi/thermal_zone/*/polling_frequency
If the value in temperature is not updated automatically when
the temperature changes, the polling mode can be toggled here. The
command echo X > /proc/acpi/thermal_zone/*/polling_-
frequency causes the temperature to be queried every X seconds.
Set X=0 to disable polling.
17.3.2 The ACPI Daemon (acpid)
Like the APM daemon, the ACPI daemon processes certain events. Cur-
rently, the only supported events are the actuation of switches, such as
the power button or the lid contact. All events are logged in the system
log. Set the actions to perform in response to these events in the variables
ACPI_BUTTON_POWER and ACPI_BUTTON_LID in /etc/sysconfig/
365SUSE LINUX Enterprise Server