-Decide yourself whether you want to enable Software Suspend, Suspend-to-Disk
-and Sleep States (see below). If you own an ASUS, Medion or Toshiba laptop,
-enable the appropriate section.
+Decide yourself whether you want to enable Software Suspend, Suspend-to-Disk and
+Sleep States (see below). If you own an ASUS, Medion or Toshiba laptop, enable
+the appropriate section. Recent kernel versions (2.6.9 and later) include an
+
+The kernel has to know how to enable CPU frequency scaling on your processor. As
+each type of CPU has a different interface, you've got to choose the right
+driver for your processor. Be careful here - enabling
@@ -230,70 +240,106 @@
Typical ACPI events are closing the lid, changing the power source or pressing
-the sleep button. Every acpi event recognized by the kernel is catched by acpid
-which calls
-#!/bin/sh
-
-set $*
-
-group=${1/\/*/}
-action=${1/*\//}
-
-# runlevel to use in AC mode
-RLVL_AC="default"
-# runlevel to use in battery mode
-RLVL_BATTERY="battery"
-
-# file indicating the AC state. Verify the filename before using
-AC_STATE="/proc/acpi/ac_adapter/AC/state"
-# this string means running on AC
-AC_ON="on-line"
-# this string means running on batteries
-AC_OFF="off-line"
+the sleep button. Create the following files to switch between default
+and battery runlevel depending on the power source:
+
+
+
+#!/bin/bash
+
+# This runlevel will be used in AC mode
+#RUNLEVEL_AC="default"
+
+# This runlevel will be used in battery mode
+#RUNLEVEL_BATTERY="battery"
+
+# This file indicates the AC state
+# It's location may vary on your system. The script checks for
+# /proc/acpi/ac_adapter/AC/state, /proc/acpi/ac_adapter/AC0/state,
+# /proc/acpi/ac_adapter/AC1/state and /proc/acpi/ac_adapter/AC2/state
+# If it is something else on your system, uncomment the next line
+# and change appropriately.
+#AC_STATE="/proc/acpi/ac_adapter/AC/state"
+
+
+
+#!/bin/bash
+
+RUNLEVEL_AC="default"
+RUNLEVEL_BATTERY="battery"
+
+if [ -f '/proc/acpi/ac_adapter/AC0/state' ]
+then
+ AC_STATE="/proc/acpi/ac_adapter/AC0/state"
+elif [ -f '/proc/acpi/ac_adapter/AC1/state' ]
+then
+ AC_STATE="/proc/acpi/ac_adapter/AC1/state"
+elif [ -f '/proc/acpi/ac_adapter/AC2/state' ]
+then
+ AC_STATE="/proc/acpi/ac_adapter/AC2/state"
+else
+ AC_STATE="/proc/acpi/ac_adapter/AC/state"
+fi
+
+
+source /etc/acpi/switch_runlevel.conf
function SwitchRunlevel() {
- if [[ "$(grep ${AC_OFF} ${AC_STATE})" != "" && "$(cat /var/lib/init.d/softlevel)" != "${RLVL_BATTERY}" ]]
+
+ if [ ! -d "/etc/runlevels/${RUNLEVEL_AC}" ]
then
- logger "Switching to ${RLVL_BATTERY} runlevel"
- /sbin/rc ${RLVL_BATTERY}
- elif [[ "$(grep ${AC_ON} ${AC_STATE})" != "" && "$(cat /var/lib/init.d/softlevel)" != "${RLVL_AC}" ]]
+ logger "${0}: Runlevel ${RUNLEVEL_AC} does not exist. Aborting."
+ exit 1
+ fi
+
+
+ if [ ! -d "/etc/runlevels/${RUNLEVEL_BATTERY}" ]
+ then
+ logger "${0}: Runlevel ${RUNLEVEL_BATTERY} does not exist. Aborting."
+ exit 1
+ fi
+
+ if [ ! -f "${AC_STATE}" ]
then
- logger "Switching to ${RLVL_AC} runlevel"
- /sbin/rc ${RLVL_AC}
+ logger "${0}: File ${AC_STATE} does not exist. Aborting"
+ exit 1
+ fi
+
+
+ if [[ "$(grep off-line ${AC_STATE})" != "" && "$(cat /var/lib/init.d/softlevel)" != "${RUNLEVEL_BATTERY}" ]]
+ then
+ logger "Switching to ${RUNLEVEL_BATTERY} runlevel"
+ /sbin/rc ${RUNLEVEL_BATTERY}
+ elif [[ "$(grep on-line ${AC_STATE})" != "" && "$(cat /var/lib/init.d/softlevel)" != "${RUNLEVEL_AC}" ]]
+ then
+ logger "Switching to ${RUNLEVEL_AC} runlevel"
+ /sbin/rc ${RUNLEVEL_AC}
fi
}
+
+
+event=ac_adapter.*
+action=/etc/acpi/actions/pmg_ac_adapter.sh %e
+
+
+
+event=battery.*
+action=/etc/acpi/actions/pmg_battery.sh %e
+
+
+
+#! /bin/bash
+
+source /etc/acpi/switch_runlevel.sh
+SwitchRunlevel
+
+
+
+#! /bin/bash
-case "$group" in
- battery)
- case "$action" in
- battery)
- SwitchRunlevel
- ;;
- *)
- logger "ACPI group battery / action $action is not defined"
- ;;
- esac
- ;;
-
- ac_adapter)
- case "$action" in
- ac_adapter)
- SwitchRunlevel
- ;;
- *)
- logger "ACPI group ac_adapter / action $action is not defined"
- ;;
- esac
- ;;
- *)
- logger "ACPI group $group / action $action is not defined"
- ;;
-esac
+source /etc/acpi/switch_runlevel.sh
+SwitchRunlevel
@@ -313,7 +359,7 @@
# Fake acpi event to switch runlevel if running on batteries
-/etc/acpi/default.sh "battery/battery"
+/etc/acpi/actions/pmg_battery.sh "battery/battery"
@@ -328,6 +374,43 @@
CPU Power Management
+Some technical terms
+
+
+
+CPU frequency scaling brings up some technical terms that might be unknown to
+you. Here's a quick introduction.
+
+
+
+First of all, the kernel has to be able to change the processor's frequency. The
+CPUfreq processor driver knows the commands to do it on your CPU. Thus
+it's important to choose the right one in your kernel. You should already have
+done it above. Once the kernel knows how to change frequencies, it has to know
+which frequency it should set. This is done according to the policy which
+consists of CPUfreq policy and a governor . A CPUfreq policy are
+just two numbers which define a range the frequency has to stay between -
+minimal and maximal frequency. The governor now decides which of the available
+frequencies in between minimal and maximal frequency to choose. For example, the
+powersave governor always chooses the lowest frequency available, the
+performance governor the highest one. The userspace governor makes
+no decision but chooses whatever the user (or a program in userspace) wants -
+which means it reads the frequency from
+/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed .
+
+
+
+This doesn't sound like dynamic frequency changes yet and in fact it isn't.
+Dynamics however can be accomplished with various approaches. For example,
+the ondemand governor makes its decisions depending on the current CPU
+load. The same is done by various userland tools like cpudyn ,
+speedfreq , powernowd and many more. ACPI events can be used to
+enable or disable dynamic frequency changes depending on power source.
+
+
+
+
+
Setting the frequency manually
@@ -394,39 +477,120 @@
The above is quite nice, but not doable in daily life. Better let your system
-set the appropriate frequency automatically. A couple of user space programs
-like to do it for you. The following table gives a quick overview to help you
-decide on one of them.
+set the appropriate frequency automatically. There are many different approaches
+to do this. The following table gives a quick overview to help you decide on one
+of them. It's roughly seperated in three categories kernel for approaches
+that only need kernel support, daemon for programs that run in the
+background and graphical for programs that provide a GUI for easy
+configuration and changes.
Name
- Pro
- Con
+ Category
+ Switch decision
+ Kernel governors
+ Further governors
+ Comments
+
+
+ 'ondemand' governor
+ Kernel
+ CPU load
+ N.A.
+ N.A.
+
+ Further tuning through files in
+ /sys/devices/system/cpu/cpu0/cpufreq/ondemand/ . Still requires
+ userland tools (programs, scripts) if governor switching or similar is
+ desired.
+
cpudyn Also supports disk standby
- Daemon
+ CPU load
+ None
+ Dynamic
+
+ Also supports disk standby - notice however that laptop mode in most
+ cases will do a better job.
+
- cpufreq Sophisticated setup possible
- Complicated setup
+ cpufreqd Daemon
+ Battery state, CPU load, running programs
+ All available
+ None
+
+ Sophisticated (but also complicated) setup. An optimal configuration
+ requires detailed knowledge of your system.
+
+
+
+
+
+
+ ncpufreqd
+
+ Daemon
+ CPU temperature
+ Powersave, performance
+ temperature governor
+
+ It's main purpose is thermal management - whenever CPU temperature exceeds
+ a user defined trip point, processor frequency will be lowered through
+ frequency scaling or ACPI throttling. Very useful for laptops with mobile
+ versions of desktops CPUs and other ones that have heat problems. See the
+ "Thermal Management" chapter for details.
+
+
+
+
+ powernowd
+
+ Daemon
+ CPU load
+ None
+ Passive, sine, aggressive
+
+ Supports SMP.
+
speedfreq Daemon
+ CPU load
+ None
+ Dynamic, powersave, performance, fixed speed
- Small yet powerful
- Useful client/server interface
+ Small yet powerful with an useful client/server interface. Requires a 2.6
+ kernel.
- Kernel 2.6 series only
- powernowd Supports SMP
- gtk-cpuspeedy Graphical
+ None
+ None
+ None
+
+ Gnome application, a graphical tool to set CPU frequency manually. It does
+ not offer any automation and is mainly listed for the sake of completeness.
+
+
+
+ klaptopdaemon
+ Graphical
+ Battery state
+ All available
+ None
+
+ KDE only, 'ondemand' governor required for dynamic frequency scaling.
+
@@ -548,9 +712,43 @@
speedfreq .
+
+
+
+Thermal Management
+
+
+
+
+There's another area where throttling CPU frequency is useful. If your laptop
+(or Desktop system) has heat problems, frequency throttling can be the only
+alternative to a shutdown. ncpufreqd is a tool that keeps an eye on
+temperature and throttles CPU frequency whenever it gets too high. Make sure
+that no other daemon like speedfreqd, cpufreqd, powernowd or cpudyn is running
+and install ncpufreqd :
+
+
+
+# emerge ncpufreqd
+# rc-update add ncpufreqd default battery
+
+
+
+ncpufreqd is configured through /etc/ncpufreqd.conf . Modify
+it and start ncpufreqd afterwards: /etc/init.d/ncpufreqd start .
+
+
+
+
+
+
+Verifying the result
+
+
+
The last thing to check is that your new policies do a good job. An easy way to
-do so is monitoring the CPU speed while working with your laptop:
+do so is monitoring CPU speed while working with your laptop:
@@ -716,23 +914,21 @@
-To start and stop laptop-mode, create a script /etc/init.d/laptop-mode. You can
-take the one included in
-/usr/src/linux/Documentation/laptop-mode.txt . Onces it's ready,
-make sure it gets called.
+Besides kernel support you also need a script that controls starting and
+stopping of laptop-mode. The package laptop-mode-tools contains it.
-# rc-update add laptop-mode battery
+# emerge laptop-mode-tools
-
-Once again: Be careful with sleep/spin down settings of your hard drive.
-Setting it to small values might wear out your drive and lose warranty. Be sure
-to read the documentation in laptop-mode.txt. Make sure to stop laptop-mode
-before your battery runs out of power and data gets written to disk - otherwise
-you will at least lose the last 10 minutes of your work.
-
+
+laptop-mode-tools has it's configuration file in
+/etc/laptop-mode/laptop-mode.conf . Adjust it the way you like it,
+it's well commented. If you have apm or acpi in your USE flags,
+laptop-mode will be started automatically in battery mode. Otherwise you can
+automate it by running rc-update add laptop-mode battery .
+
@@ -1049,6 +1245,16 @@
+Q: When configuring the kernel, powersave, performance and userspace
+governors show up, but that ondemand thing is missing. Where do I get it?
+
+
+
+A: The ondemand governor is only included in recent kernel sources. Try
+updating them.
+
+
+
Q: Battery life time seems to be worse than before.