Attachment 47563 Details for Bug 69734 – power-management-guide.diff

[patch] power-management-guide.diff

power-management-guide.diff.txt (text/plain), 17.31 KB, created by Dennis Nienhüser (RETIRED) on 2005-01-04 02:53:47 UTC

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Creator: Dennis Nienhüser (RETIRED)

Created: 2005-01-04 02:53:47 UTC

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>--- power-management-guide-1.17.xml	2004-10-15 22:33:00.000000000 +0200
>+++ power-management-guide.xml	2005-01-04 11:46:54.934550552 +0100
>@@ -5,7 +5,7 @@
> <title>Power Management Guide</title>
> 
> <author title="Author">
>- <mail link="fragfred@gmx.de">Dennis Nienh&#252;ser</mail>
>+ <mail link="fragfred@gmx.de">Dennis NienhÃ¼ser</mail>
> </author>
> 
> <abstract>
>@@ -17,8 +17,8 @@
> 
> <license/>
> 
>-<version>1.17</version>
>-<date>October 10, 2004</date>
>+<version>1.18</version>
>+<date>January 02, 2005</date>
> 
> <chapter>
> <title>Introduction</title>
>@@ -164,15 +164,26 @@
> Default CPUFreq governor (userspace)
> &lt;*&gt; 'performance' governor
> &lt;*&gt; 'powersave' governor
>+ &lt;*&gt; 'ondemand' cpufreq policy governor
> &lt;*&gt; CPU frequency table helpers
> &lt;M&gt; ACPI Processor P-States driver
> &lt;*&gt; CPUFreq driver for your processor
> </pre>
> 
> 
>-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
>+<e>'ondemand' governor</e> for CPU Frequency Scaling, activate it as well when
>+using such a kernel.
>+
>+
>+
>+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 <e>Intel Pentium 4 clock
>+modulation</e> on a Pentium M system will lead to strange results for example.
>+Consult the kernel documentation if you're unsure which one to take.
> 
> 
> 
>@@ -230,70 +241,102 @@
> 
> 
> 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 <path>/etc/acpi/default.sh</path>. Here is a basic modification
>-supporting runlevel switching:
>-
>-
>-<pre caption="Event driven runlevel switching with acpid">
>-#!/bin/sh
>-
>-set $*
>-
>-group=${1/\/*/}
>-action=${1/*\//}
>-
>-<comment># runlevel to use in AC mode</comment>
>-RLVL_AC="default"
>-<comment># runlevel to use in battery mode</comment>
>-RLVL_BATTERY="battery"
>-
>-<comment># file indicating the AC state. Verify the filename before using</comment>
>-AC_STATE="/proc/acpi/ac_adapter/AC/state"
>-<comment># this string means running on AC</comment>
>-AC_ON="on-line"
>-<comment># this string means running on batteries</comment>
>-AC_OFF="off-line"
>+the sleep button. An important event is changing the power source, which should
>+cause a runlevel switch. This can be done with a script which gets called from
>+acpid. The script needs the package <c>sys-apps/powermgmt-base</c>, so let's
>+first install that. You may have to unmask powermgmt-base, see the Gentoo
>+Handbook for details on how to do that.
>+
>+
>+<pre caption="Emerging dependency powermgmt-base">
>+# emerge powermgmt-base
>+</pre>
>+
>+
>+Create the following files to switch between <e>default</e>
>+and <e>battery</e> runlevel depending on the power source:
>+
>+
>+<pre caption="/etc/acpi/switch_runlevel.conf">
>+#!/bin/bash
>+
>+# This runlevel will be used in AC mode
>+#RUNLEVEL_AC="default"
>+
>+# This runlevel will be used in battery mode
>+#RUNLEVEL_BATTERY="battery"
>+</pre>
>+
>+<pre caption="/etc/acpi/switch_runlevel.sh">
>+#!/bin/bash
>+
>+RUNLEVEL_AC="default"
>+RUNLEVEL_BATTERY="battery"
>+
>+source /etc/acpi/switch_runlevel.conf
> 
> function SwitchRunlevel() {
>- if [[ "$(grep ${AC_OFF} ${AC_STATE})" != "" &amp;&amp; "$(cat /var/lib/init.d/softlevel)" != "${RLVL_BATTERY}" ]]
>+
>+ if [ ! -d "/etc/runlevels/${RUNLEVEL_AC}" ]
>+ then
>+ logger "${0}: Runlevel ${RUNLEVEL_AC} does not exist. Aborting."
>+ exit 1
>+ fi
>+
>+
>+ if [ ! -d "/etc/runlevels/${RUNLEVEL_BATTERY}" ]
>+ then
>+ logger "${0}: Runlevel ${RUNLEVEL_BATTERY} does not exist. Aborting."
>+ exit 1
>+ fi
>+
>+ if on_ac_power
>+ then if [[ "$(cat /var/lib/init.d/softlevel)" != "${RUNLEVEL_AC}" ]]
> then
>- logger "Switching to ${RLVL_BATTERY} runlevel"
>- /sbin/rc ${RLVL_BATTERY}
>- elif [[ "$(grep ${AC_ON} ${AC_STATE})" != "" &amp;&amp; "$(cat /var/lib/init.d/softlevel)" != "${RLVL_AC}" ]]
>+ logger "Switching to ${RUNLEVEL_AC} runlevel"
>+ /sbin/rc ${RUNLEVEL_AC}
>+ fi
>+ elif [[ "$(cat /var/lib/init.d/softlevel)" != "${RUNLEVEL_BATTERY}" ]]
> then
>- logger "Switching to ${RLVL_AC} runlevel"
>- /sbin/rc ${RLVL_AC}
>+ logger "Switching to ${RUNLEVEL_BATTERY} runlevel"
>+ /sbin/rc ${RUNLEVEL_BATTERY}
> fi
> }
>+</pre>
>+
>+<pre caption="/etc/acpi/events/pmg_ac_adapter">
>+event=ac_adapter.*
>+action=/etc/acpi/actions/pmg_ac_adapter.sh %e
>+</pre>
>+
>+<pre caption="/etc/acpi/events/pmg_battery">
>+event=battery.*
>+action=/etc/acpi/actions/pmg_battery.sh %e
>+</pre>
>+
>+<pre caption="/etc/acpi/actions/pmg_ac_adapter.sh">
>+#! /bin/bash
>+
>+source /etc/acpi/switch_runlevel.sh
>+SwitchRunlevel
>+</pre>
>+
>+<pre caption="/etc/acpi/actions/pmg_battery.sh">
>+#! /bin/bash
>+
>+source /etc/acpi/switch_runlevel.sh
>+SwitchRunlevel
>+</pre>
> 
>+
>+Some of these files must be executable. Last not least restart acpid to have
>+it recognize the changes.
>+
> 
>-case "$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
>+<pre caption="Finishing runlevel switching with acpid">
>+# chmod +x /etc/acpi/switch_runlevel.sh
>+# chmod +x /etc/acpi/actions/pmg_*
>+# /etc/init.d/acpid restart
> </pre>
> 
> 
>@@ -304,7 +347,7 @@
> 
> Due to the nature of the event mechanism, your laptop will boot into runlevel
> <e>default</e> regardless of the AC/battery state. You can add another entry
>-to the boot loader with <c>softlevel=boot</c>, but it's likely to forget
>+to the boot loader with <c>softlevel=battery</c>, but it's likely to forget
> choosing it. A better way is faking an ACPI event in the end of the boot
> process and let the <path>/etc/acpi/default.sh</path> script decide whether a
> runlevel change is necessary. Open <path>/etc/conf.d/local.start</path> in your
>@@ -313,7 +356,7 @@
> 
> <pre caption="Runlevel switch at boot time by editing local.start">
> <comment># Fake acpi event to switch runlevel if running on batteries</comment>
>-/etc/acpi/default.sh "battery/battery"
>+/etc/acpi/actions/pmg_battery.sh "battery/battery"
> </pre>
> 
> 
>@@ -328,6 +371,43 @@
> <chapter>
> <title>CPU Power Management</title>
> <section>
>+<title>Some technical terms</title>
>+<body>
>+
>+
>+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
>+<e>CPUfreq processor driver</e> 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 <e>policy</e> which
>+consists of <e>CPUfreq policy</e> and a <e>governor</e>. 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
>+<e>powersave governor</e> always chooses the lowest frequency available, the
>+<e>performance governor</e> the highest one. The <e>userspace governor</e> makes
>+no decision but chooses whatever the user (or a program in userspace) wants -
>+which means it reads the frequency from
>+<path>/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed</path>.
>+
>+
>+
>+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 <e>ondemand governor</e> makes its decisions depending on the current CPU
>+load. The same is done by various userland tools like <c>cpudyn</c>,
>+<c>speedfreq</c>, <c>powernowd</c> and many more. ACPI events can be used to
>+enable or disable dynamic frequency changes depending on power source.
>+
>+
>+</body>
>+</section>
>+<section>
> <title>Setting the frequency manually</title>
> <body>
> 
>@@ -394,39 +474,101 @@
> 
> 
> 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 <e>kernel</e> for approaches
>+that only need kernel support, <e>daemon</e> for programs that run in the
>+background and <e>graphical</e> for programs that provide a GUI for easy
>+configuration and changes.
> 
> 
> <table>
> <tr>
> <th>Name</th>
>- <th>Pro</th>
>- <th>Con</th>
>+ <th>Category</th>
>+ <th>Switch decision</th>
>+ <th>Kernel governors</th>
>+ <th>Further governors</th>
>+ <th>Comments</th>
>+</tr>
>+<tr>
>+ <ti>'ondemand' governor</ti>
>+ <ti>Kernel</ti>
>+ <ti>CPU load</ti>
>+ <ti>N.A.</ti>
>+ <ti>N.A.</ti>
>+ <ti>
>+ Further tuning through files in
>+ <path>/sys/devices/system/cpu/cpu0/cpufreq/ondemand/</path>. Still requires
>+ userland tools (programs, scripts) if governor switching or similar is
>+ desired.
>+ </ti>
> </tr>
> <tr>
> <ti><uri link="http://mnm.uib.es/~gallir/cpudyn/">cpudyn</uri></ti>
>- <ti>Also supports disk standby</ti>
>- <ti></ti>
>+ <ti>Daemon</ti>
>+ <ti>CPU load</ti>
>+ <ti>None</ti>
>+ <ti>Dynamic</ti>
>+ <ti>
>+ Also supports disk standby - notice however that <e>laptop mode</e> in most
>+ cases will do a better job.
>+ </ti>
>+</tr>
>+<tr>
>+ <ti><uri link="http://sourceforge.net/projects/cpufreqd/">cpufreqd</uri></ti>
>+ <ti>Daemon</ti>
>+ <ti>Battery state, CPU load, running programs</ti>
>+ <ti>All available</ti>
>+ <ti>None</ti>
>+ <ti>
>+ Sophisticated (but also complicated) setup. An optimal configuration
>+ requires detailed knowledge of your system.
>+ </ti>
> </tr>
> <tr>
>- <ti><uri link="http://sourceforge.net/projects/cpufreqd/">cpufreq</uri></ti>
>- <ti>Sophisticated setup possible</ti>
>- <ti>Complicated setup</ti>
>+ <ti>
>+ <uri link="http://www.deater.net/john/powernowd.html">powernowd</uri>
>+ </ti>
>+ <ti>Daemon</ti>
>+ <ti>CPU load</ti>
>+ <ti>None</ti>
>+ <ti>Passive, sine, aggressive</ti>
>+ <ti>
>+ Supports SMP.
>+ </ti>
> </tr>
> <tr>
> <ti><uri link="http://www.goop.org/~jeremy/speedfreq/">speedfreq</uri></ti>
>+ <ti>Daemon</ti>
>+ <ti>CPU load</ti>
>+ <ti>None</ti>
>+ <ti>Dynamic, powersave, performance, fixed speed</ti>
> <ti>
>- Small yet powerful 
>- Useful client/server interface
>+ Small yet powerful with an useful client/server interface. Requires a 2.6
>+ kernel.
> </ti>
>- <ti>Kernel 2.6 series only</ti>
> </tr>
> <tr>
>- <ti><uri link="http://www.deater.net/john/powernowd.html">powernowd</uri></ti>
>- <ti>Supports SMP</ti>
>- <ti></ti>
>+ <ti><uri link="http://cpuspeedy.sourceforge.net/">gtk-cpuspeedy</uri></ti>
>+ <ti>Graphical</ti>
>+ <ti>None</ti>
>+ <ti>None</ti>
>+ <ti>None</ti>
>+ <ti>
>+ 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.
>+ </ti>
>+</tr>
>+<tr>
>+ <ti>klaptopdaemon</ti>
>+ <ti>Graphical</ti>
>+ <ti>Battery state</ti>
>+ <ti>All available</ti>
>+ <ti>None</ti>
>+ <ti>
>+ KDE only, 'ondemand' governor required for dynamic frequency scaling.
>+ </ti>
> </tr>
> </table>
> 
>@@ -458,13 +600,13 @@
> </pre>
> 
> 
>-Setting up cpufreq is a little bit more complicated.
>+Setting up cpufreqd is a little bit more complicated.
> 
> 
> <warn>
> Do not run more than one of the above programs at the same time. It may cause
> confusion like switching between two frequencies all the time. If you just
>-installed speedfreq, skip cpufreq now.
>+installed speedfreq, skip cpufreqd now.
> </warn>
> 
> <pre caption="Installing cpufreqd">
>@@ -548,9 +690,17 @@
> <c>speedfreq</c>.
> 
> 
>+</body>
>+</section>
>+
>+<section>
>+<title>Verifying the result</title>
>+
>+<body>
>+
> 
> 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:
> 
> 
> <pre caption="Monitoring CPU speed">
>@@ -715,25 +865,42 @@
> 
> 
> 
>-
>-To start and stop laptop-mode, create a script /etc/init.d/laptop-mode. You can
>-take the one included in
>-<path>/usr/src/linux/Documentation/laptop-mode.txt</path>. 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. You kernel documentation in
>+<path>/usr/src/linux/Documentation/laptop-mode.txt</path> contains one as well
>+as the package <c>laptop-mode-tools</c>. None of them is easy to install
>+though.
> 
> 
>-<pre caption="Automatic start of laptop-mode">
>-# rc-update add laptop-mode battery
>-</pre>
>+
>+Ebuilds for laptop-mode-tools are not in Portage, because Gentoo developers
>+don't think they are production ready yet. Take that into consideration
>+before using the ebuilds which can be found in <uri
>+link="http://bugs.gentoo.org/show_bug.cgi?id=45593">Bugzilla</uri>. The Gentoo
>+Handbook tells you how to use external ebuilds if you don't know where to put
>+them. Once your PORTDIR_OVERLAY contains the ebuilds, install the
>+script:
>+
> 
> <warn>
>-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.
>+This package is not seen as production ready and installing custom ebuilds from
>+Bugzilla is not recommended. Please don't use laptop-mode-tools if you're
>+unsure.
> </warn>
> 
>+<pre caption="Automated start of laptop-mode">
>+# emerge laptop-mode-tools
>+</pre>
>+
>+
>+<c>laptop-mode-tools</c> has it's configuration file in
>+<path>/etc/laptop-mode/laptop-mode.conf</path>. Adjust it the way you like it,
>+it's well commented. If you have <e>apm</e> or <e>acpi</e> in your USE flags,
>+laptop-mode will be started automatically in battery mode. Otherwise you can
>+automate it by running <c>rc-update add laptop-mode battery</c>.
>+
>+
> </body>
> </section>
> <section>
>@@ -948,17 +1115,17 @@
> # echo 3 &gt; /proc/acpi/sleep <comment>(sleep)</comment>
> 
> <comment>(kernel 2.6 series)</comment>
>-# echo -n standby &gt; /sys/power/state <comment>standby</comment>
>-# echo -n mem &gt; /sys/power/state <comment>sleep</comment>
>+# echo -n standby &gt; /sys/power/state <comment>(standby)</comment>
>+# echo -n mem &gt; /sys/power/state <comment>(sleep)</comment>
> 
> <comment>(swsusp)</comment>
>-# echo 4 &gt; /proc/acpi/sleep <comment>hibernate</comment>
>+# echo 4 &gt; /proc/acpi/sleep <comment>(hibernate)</comment>
> 
> <comment>(Suspend-to-Disk)</comment>
>-# echo -n disk &gt; /sys/power/state <comment>hibernate</comment>
>+# echo -n disk &gt; /sys/power/state <comment>(hibernate)</comment>
> 
> <comment>(swsusp2)</comment>
>-# echo &gt; /proc/swsusp/activate
>+# /usr/sbin/hibernate <comment>(hibernate, see below)</comment>
> </pre>
> 
> <warn>
>@@ -976,12 +1143,20 @@
> 
> While the above should be sufficient to get swsusp and Suspend-to-Disk running
> (I didn't say working), swsusp2 needs special care. 
>-The first thing to do is to patch the kernel with the patches provided at <uri
>+The first thing to do is patching the kernel with the patches provided at <uri
> link="http://softwaresuspend.berlios.de/">
>-http://softwaresuspend.berlios.de/</uri>. Afterwards, install the hibernate 
>-script from the same page.
>+http://softwaresuspend.berlios.de/</uri>. Additionally you've got to emerge
>+<c>hibernate-script</c>. Once it is installed, configure
>+<path>/etc/hibernate/hibernate.conf</path> and try whether it works:
> 
> 
>+<pre>
>+# emerge hibernate-script
>+# $EDITOR /etc/hibernate/hibernate.conf
>+<comment>(Last chance to backup any data)</comment>
>+# hibernate
>+</pre>
>+
> </body>
> </section>
> </chapter>
>@@ -1049,6 +1224,16 @@
> 
> 
> 
>+<e>Q:</e> When configuring the kernel, powersave, performance and userspace
>+governors show up, but that ondemand thing is missing. Where do I get it?
>+
>+
>+
>+<e>A:</e> The ondemand governor is only included in recent kernel sources. Try
>+updating them.
>+
>+
>+
> <e>Q:</e> Battery life time seems to be worse than before.
> 
>

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