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1	<?xml version='1.0' encoding="UTF-8"?>	1	<?xml version='1.0' encoding="UTF-8"?>
2	<!DOCTYPE guide SYSTEM "/dtd/guide.dtd">	2	<!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
3	<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/power-management-guide.xml,v 1.11 2005/04/18 19:19:27 dertobi123 Exp $ -->	3	<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/power-management-guide.xml,v 1.12 2005/05/04 16:54:18 neysx Exp $ -->
4	<guide link="power-management-guide.xml">	4	<guide link="power-management-guide.xml">
5	<title>Power Management Guide</title>	5	<title>Power Management Guide</title>
6		6
7	<author title="Author">	7	<author title="Author">
8	<mail link="fragfred@gmx.de">Dennis Nienhüser</mail>	8	<mail link="fragfred@gmx.de">Dennis Nienhüser</mail>
…		…
15		15
16	<!-- The content of this document is licensed under the CC-BY-SA license -->	16	<!-- The content of this document is licensed under the CC-BY-SA license -->
17	<!-- See http://creativecommons.org/licenses/by-sa/2.0 -->	17	<!-- See http://creativecommons.org/licenses/by-sa/2.0 -->
18	<license/>	18	<license/>
19		19
20	<version>1.21</version>	20	<version>1.22</version>
21	<date>2005-04-18</date>	21	<date>2005-05-04</date>
22		22
23	<chapter>	23	<chapter>
24	<title>Introduction</title>	24	<title>Introduction</title>
25
26	<section>	25	<section>
27	<title>Why Power Management?</title>	26	<title>Why Power Management?</title>
28
29	<body>	27	<body>
30		28
31	<p>	29	<p>
32	Capacity and lifetime of laptop batteries has improved much in the last years.	30	Capacity and lifetime of laptop batteries has improved much in the last years.
33	Nevertheless modern processors consume much more energy than older ones and	31	Nevertheless modern processors consume much more energy than older ones and
…		…
147	[ ] Suspend-to-Disk Support	145	[ ] Suspend-to-Disk Support
148		146
149	ACPI( Advanced Configuration and Power Interface ) Support --->	147	ACPI( Advanced Configuration and Power Interface ) Support --->
150	[*] ACPI Support	148	[*] ACPI Support
151	[ ] Sleep States	149	[ ] Sleep States
152	<M> AC Adapter	150	[*] AC Adapter
153	<M> Battery	151	[*] Battery
154	<M> Button	152	<M> Button
155	<M> Fan	153	<M> Fan
156	<M> Processor	154	<M> Processor
157	<M> Thermal Zone	155	<M> Thermal Zone
158	< > ASUS/Medion Laptop Extras	156	< > ASUS/Medion Laptop Extras
…		…
171	</pre>	169	</pre>
172		170
173	<p>	171	<p>
174	Decide yourself whether you want to enable Software Suspend, Suspend-to-Disk and	172	Decide yourself whether you want to enable Software Suspend, Suspend-to-Disk and
175	Sleep States (see below). If you own an ASUS, Medion or Toshiba laptop, enable	173	Sleep States (see below). If you own an ASUS, Medion or Toshiba laptop, enable
176	the appropriate section. Recent kernel versions (2.6.9 and later) include an	174	the appropriate section.
177	<e>'ondemand' governor</e> for CPU Frequency Scaling, activate it as well when
178	using such a kernel.
179	</p>	175	</p>
180		176
181	<p>	177	<p>
182	The kernel has to know how to enable CPU frequency scaling on your processor. As	178	The kernel has to know how to enable CPU frequency scaling on your processor. As
183	each type of CPU has a different interface, you've got to choose the right	179	each type of CPU has a different interface, you've got to choose the right
…		…
188		184
189	<p>	185	<p>
190	Compile your kernel, make sure the right modules get loaded at startup and boot	186	Compile your kernel, make sure the right modules get loaded at startup and boot
191	into your new ACPI-enabled kernel. Next run <c>emerge sys-power/acpid</c> to get	187	into your new ACPI-enabled kernel. Next run <c>emerge sys-power/acpid</c> to get
192	the acpi daemon. This one informs you about events like switching from AC to	188	the acpi daemon. This one informs you about events like switching from AC to
193	battery or closing the lid. Make sure the module <e>button</e> is loaded if you	189	battery or closing the lid. Make sure the modules are loaded if you didn't
194	didn't compile it into the kernel and start acpid with <c>/etc/init.d/acpid	190	compile them into the kernel and start acpid by executing
195	start</c>. Run <c>rc-update add acpid default</c> to load it on startup. You'll	191	<c>/etc/init.d/acpid start</c>. Run <c>rc-update add acpid default</c> to load
196	soon see how to use it.	192	it on startup. You'll soon see how to use it.
197	</p>	193	</p>
198		194
199	<pre caption="Installing acpid">	195	<pre caption="Installing acpid">
200	# <i>emerge sys-power/acpid</i>	196	# <i>emerge sys-power/acpid</i>
201	# <i>modprobe button</i>
202	# <i>/etc/init.d/acpid start</i>	197	# <i>/etc/init.d/acpid start</i>
203	# <i>rc-update add acpid default</i>	198	# <i>rc-update add acpid default</i>
204	</pre>	199	</pre>
205		200
206	</body>	201	</body>
…		…
244	the sleep button. An important event is changing the power source, which should	239	the sleep button. An important event is changing the power source, which should
245	cause a runlevel switch. Create the following files to switch between	240	cause a runlevel switch. Create the following files to switch between
246	<e>default</e> and <e>battery</e> runlevel depending on the power source:	241	<e>default</e> and <e>battery</e> runlevel depending on the power source:
247	</p>	242	</p>
248		243
249	<pre caption="/etc/acpi/switch_runlevel.sh">	244	<pre caption="/etc/acpi/actions/pmg_switch_runlevel.sh">
250	#!/bin/bash	245	#!/bin/bash
251		246
		247	<comment># BEGIN configuration</comment>
252	RUNLEVEL_AC="default"	248	RUNLEVEL_AC="default"
253	RUNLEVEL_BATTERY="battery"	249	RUNLEVEL_BATTERY="battery"
		250	<comment># END configuration</comment>
254		251
255	function on_ac () {
256	if which on_ac_power &> /dev/null
257	then
258	on_ac_power
259	else
260	grep --quiet on-line /proc/acpi/ac_adapter/*/state
261	fi
262	}
263		252
264	function SwitchRunlevel () {
265
266	if [ ! -d "/etc/runlevels/${RUNLEVEL_AC}" ]	253	if [ ! -d "/etc/runlevels/${RUNLEVEL_AC}" ]
267	then	254	then
268	logger "${0}: Runlevel ${RUNLEVEL_AC} does not exist. Aborting."	255	logger "${0}: Runlevel ${RUNLEVEL_AC} does not exist. Aborting."
269	exit 1	256	exit 1
270	fi	257	fi
271		258
272
273	if [ ! -d "/etc/runlevels/${RUNLEVEL_BATTERY}" ]	259	if [ ! -d "/etc/runlevels/${RUNLEVEL_BATTERY}" ]
274	then	260	then
275	logger "${0}: Runlevel ${RUNLEVEL_BATTERY} does not exist. Aborting."	261	logger "${0}: Runlevel ${RUNLEVEL_BATTERY} does not exist. Aborting."
276	exit 1	262	exit 1
277	fi	263	fi
278		264
279	if on_ac	265	if on_ac_power
		266	then
280	then if [[ "$(cat /var/lib/init.d/softlevel)" != "${RUNLEVEL_AC}" ]]	267	if [[ "$(cat /var/lib/init.d/softlevel)" != "${RUNLEVEL_AC}" ]]
281	then	268	then
282	logger "Switching to ${RUNLEVEL_AC} runlevel"	269	logger "Switching to ${RUNLEVEL_AC} runlevel"
283	/sbin/rc ${RUNLEVEL_AC}	270	/sbin/rc ${RUNLEVEL_AC}
284	fi	271	fi
285	elif [[ "$(cat /var/lib/init.d/softlevel)" != "${RUNLEVEL_BATTERY}" ]]	272	elif [[ "$(cat /var/lib/init.d/softlevel)" != "${RUNLEVEL_BATTERY}" ]]
286	then	273	then
287	logger "Switching to ${RUNLEVEL_BATTERY} runlevel"	274	logger "Switching to ${RUNLEVEL_BATTERY} runlevel"
288	/sbin/rc ${RUNLEVEL_BATTERY}	275	/sbin/rc ${RUNLEVEL_BATTERY}
289	fi	276	fi
290	}
291	</pre>	277	</pre>
292		278
293	<pre caption="/etc/acpi/events/pmg_ac_adapter">	279	<pre caption="/etc/acpi/events/pmg_ac_adapter">
		280	<comment># replace "ac_adapter" below with the event generated on your laptop</comment>
		281	<comment># See /var/log/acpid</comment>
294	event=ac_adapter.*	282	event=ac_adapter.*
295	action=/etc/acpi/actions/pmg_ac_adapter.sh %e	283	action=/etc/acpi/actions/pmg_switch_runlevel.sh %e
296	</pre>	284	</pre>
297		285
298	<pre caption="/etc/acpi/events/pmg_battery">	286	<pre caption="/etc/acpi/events/pmg_battery">
		287	<comment># replace "battery" below with the event generated on your laptop</comment>
		288	<comment># See /var/log/acpid</comment>
299	event=battery.*	289	event=battery.*
300	action=/etc/acpi/actions/pmg_battery.sh %e	290	action=/etc/acpi/actions/pmg_switch_runlevel.sh %e
301	</pre>	291	</pre>
302		292
303	<pre caption="/etc/acpi/actions/pmg_ac_adapter.sh">
304	#!/bin/bash
305
306	source /etc/acpi/switch_runlevel.sh
307	SwitchRunlevel
308	</pre>
309
310	<pre caption="/etc/acpi/actions/pmg_battery.sh">
311	#!/bin/bash
312
313	source /etc/acpi/switch_runlevel.sh
314	SwitchRunlevel
315	</pre>
316
317	<p>	293	<p>
318	Some of these files must be executable. Last not least restart acpid to have	294	Additionally you need the package sys-power/powermgmt-base which contains
319	it recognize the changes.	295	the <c>on_ac_power</c> utility. The file <path>pmg_switch_runlevel.sh</path>
		296	must be executable.
320	</p>	297	</p>
321		298
322	<pre caption="Finishing runlevel switching with acpid">	299	<pre caption="Finishing runlevel switching with acpid">
323	<i># emerge powermgmt-base</i>	300	<i># emerge powermgmt-base</i>
324	<i># chmod +x /etc/acpi/switch_runlevel.sh</i>	301	<i># chmod +x /etc/acpi/actions/pmg_switch_runlevel.sh</i>
325	<i># chmod +x /etc/acpi/actions/pmg_*</i>
326	<i># /etc/init.d/acpid restart</i>	302	<i># /etc/init.d/acpid restart</i>
327	</pre>	303	</pre>
328		304
329	<p>	305	<p>
330	Give it a try: Plug AC in and out and watch syslog for the "Switching to AC	306	Give it a try: Plug AC in and out and watch syslog for the "Switching to AC
…		…
342	favourite editor and add these lines:	318	favourite editor and add these lines:
343	</p>	319	</p>
344		320
345	<pre caption="Runlevel switch at boot time by editing local.start">	321	<pre caption="Runlevel switch at boot time by editing local.start">
346	<comment># Fake acpi event to switch runlevel if running on batteries</comment>	322	<comment># Fake acpi event to switch runlevel if running on batteries</comment>
347	/etc/acpi/actions/pmg_battery.sh "battery/battery"	323	/etc/acpi/actions/pmg_switch_runlevel.sh "battery/battery"
348	</pre>	324	</pre>
349		325
350	<p>	326	<p>
351	Prepared like this you can activate Power Management policies for individual	327	Prepared like this you can activate Power Management policies for individual
352	devices.	328	devices.
…		…
371	First of all, the kernel has to be able to change the processor's frequency. The	347	First of all, the kernel has to be able to change the processor's frequency. The
372	<e>CPUfreq processor driver</e> knows the commands to do it on your CPU. Thus	348	<e>CPUfreq processor driver</e> knows the commands to do it on your CPU. Thus
373	it's important to choose the right one in your kernel. You should already have	349	it's important to choose the right one in your kernel. You should already have
374	done it above. Once the kernel knows how to change frequencies, it has to know	350	done it above. Once the kernel knows how to change frequencies, it has to know
375	which frequency it should set. This is done according to the <e>policy</e> which	351	which frequency it should set. This is done according to the <e>policy</e> which
376	consists of <e>CPUfreq policy</e> and a <e>governor</e>. A CPUfreq policy are	352	consists of a <e>CPUfreq policy</e> and a <e>governor</e>. A CPUfreq policy are
377	just two numbers which define a range the frequency has to stay between -	353	just two numbers which define a range the frequency has to stay between -
378	minimal and maximal frequency. The governor now decides which of the available	354	minimal and maximal frequency. The governor now decides which of the available
379	frequencies in between minimal and maximal frequency to choose. For example, the	355	frequencies in between minimal and maximal frequency to choose. For example, the
380	<e>powersave governor</e> always chooses the lowest frequency available, the	356	<e>powersave governor</e> always chooses the lowest frequency available, the
381	<e>performance governor</e> the highest one. The <e>userspace governor</e> makes	357	<e>performance governor</e> the highest one. The <e>userspace governor</e> makes
…		…
387	<p>	363	<p>
388	This doesn't sound like dynamic frequency changes yet and in fact it isn't.	364	This doesn't sound like dynamic frequency changes yet and in fact it isn't.
389	Dynamics however can be accomplished with various approaches. For example,	365	Dynamics however can be accomplished with various approaches. For example,
390	the <e>ondemand governor</e> makes its decisions depending on the current CPU	366	the <e>ondemand governor</e> makes its decisions depending on the current CPU
391	load. The same is done by various userland tools like <c>cpudyn</c>,	367	load. The same is done by various userland tools like <c>cpudyn</c>,
392	<c>speedfreq</c>, <c>powernowd</c> and many more. ACPI events can be used to	368	<c>cpufreqd</c>, <c>powernowd</c> and many more. ACPI events can be used to
393	enable or disable dynamic frequency changes depending on power source.	369	enable or disable dynamic frequency changes depending on power source.
394	</p>	370	</p>
395		371
396	</body>	372	</body>
397	</section>	373	</section>
…		…
412	of supported processors in the <e>Troubleshooting</e> section to verify your's	388	of supported processors in the <e>Troubleshooting</e> section to verify your's
413	is supported.	389	is supported.
414	</note>	390	</note>
415		391
416	<p>	392	<p>
417	It's time to test whether CPU frequency changing works. To get comfortable with	393	It's time to test whether CPU frequency changing works. Let's install another
418	the interface to the kernel, first do some manual speed modifications. To set	394	tool which is very handy for debugging purposes: <c>sys-power/cpufrequtils</c>
419	another CPU speed, use:
420	</p>
421
422	<pre caption="Manual CPU speed modifications">
423	<comment>(Get current frequency)</comment>
424	# <i>grep "cpu MHz" /proc/cpuinfo</i>
425
426	<comment>(Lists supported frequencies. This might fail.)</comment>
427	# <i>cd /sys/devices/system/cpu/cpu0/cpufreq/</i>
428	# <i>cat scaling_available_frequencies</i>
429
430	<comment>(Change frequency to 1 GHz (1000000 KHz)
431	Replace with a frequency your laptop supports.)</comment>
432	# <i>echo -n userspace > scaling_governor</i>
433	# <i>echo -n 1000000 > scaling_setspeed</i>
434
435	<comment>(Verify frequency was changed)</comment>
436	# <i>grep "cpu MHz" /proc/cpuinfo</i>
437	</pre>
438
439	<p>	395	</p>
440	If you are getting error messages, please refer to the <e>Troubleshooting</e>	396
441	chapter in the end of this guide.	397	<pre caption="Checking CPU frequency">
		398	# <i>emerge cpufrequtils</i>
		399	# <i>cpufreq-info</i>
		400	</pre>
		401
442	</p>	402	<p>
443		403	Here is an example output:
444	<p>	404	</p>
445	You can also write to <path>scaling_max_freq</path> and	405
446	<path>scaling_min_freq</path> to set boundaries the frequency should stay in	406	<pre caption="Sample output from cpufreq-info">
447	between.	407	cpufrequtils 0.2: cpufreq-info (C) Dominik Brodowski 2004
		408	Report errors and bugs to linux@brodo.de, please.
		409	analyzing CPU 0:
		410	driver: centrino
		411	CPUs which need to switch frequency at the same time: 0
		412	hardware limits: 600 MHz - 1.40 GHz
		413	available frequency steps: 600 MHz, 800 MHz, 1000 MHz, 1.20 GHz, 1.40 GHz
		414	available cpufreq governors: ondemand, powersave, userspace, performance
		415	current policy: frequency should be within 924 MHz and 1.40 GHz.
		416	The governor "performance" may decide which speed to use
		417	within this range.
		418	current CPU frequency is 1.40 GHz (asserted by call to hardware).
		419	</pre>
		420
448	</p>	421	<p>
449		422	Now play around with <c>cpufreq-set</c> to make sure frequency switching works.
450	<note>	423	Run <c>cpufreq-set -g ondemand</c> for example to activate the ondemand
451	Some kernel seem to be buggy about updating <path>/proc/cpuinfo</path>. If you	424	governor and verify the change with <c>cpufreq-info</c>. If it doesn't work as
452	don't see any change there, this doesn't neccessarily mean the CPU frequency	425	expected, you might find help in the Troubleshooting section in the end of this
453	wasn't changed. If this happens to you, run <c>emerge x86info</c>, update your	426	guide.
454	kernel as asked and check the current frequency with <c>x86info -mhz</c>.	427	</p>
455	</note>
456		428
457	</body>	429	</body>
458	</section>	430	</section>
459	<section>	431	<section>
460	<title>Automated frequency adaption</title>	432	<title>Automated frequency adaption</title>
…		…
494	</tr>	466	</tr>
495	<tr>	467	<tr>
496	<ti><uri link="http://mnm.uib.es/~gallir/cpudyn/">cpudyn</uri></ti>	468	<ti><uri link="http://mnm.uib.es/~gallir/cpudyn/">cpudyn</uri></ti>
497	<ti>Daemon</ti>	469	<ti>Daemon</ti>
498	<ti>CPU load</ti>	470	<ti>CPU load</ti>
499	<ti>None</ti>	471	<ti>Performance, powersave</ti>
500	<ti>Dynamic</ti>	472	<ti>Dynamic</ti>
501	<ti>	473	<ti>
502	Also supports disk standby - notice however that <e>laptop mode</e> in most	474	Also supports disk standby - notice however that <e>laptop mode</e> in most
503	cases will do a better job.	475	cases will do a better job.
504	</ti>	476	</ti>
…		…
508	<ti>Daemon</ti>	480	<ti>Daemon</ti>
509	<ti>Battery state, CPU load, running programs</ti>	481	<ti>Battery state, CPU load, running programs</ti>
510	<ti>All available</ti>	482	<ti>All available</ti>
511	<ti>None</ti>	483	<ti>None</ti>
512	<ti>	484	<ti>
513	Sophisticated (but also complicated) setup. An optimal configuration	485	Sophisticated (but also complicated) setup.
514	requires detailed knowledge of your system.
515	</ti>	486	</ti>
516	</tr>	487	</tr>
517	<tr>	488	<tr>
518	<ti>	489	<ti>
519	<uri link="http://www.deater.net/john/powernowd.html">powernowd</uri>	490	<uri link="http://www.deater.net/john/powernowd.html">powernowd</uri>
…		…
532	<ti>CPU load</ti>	503	<ti>CPU load</ti>
533	<ti>None</ti>	504	<ti>None</ti>
534	<ti>Dynamic, powersave, performance, fixed speed</ti>	505	<ti>Dynamic, powersave, performance, fixed speed</ti>
535	<ti>	506	<ti>
536	Small yet powerful with an useful client/server interface. Requires a 2.6	507	Small yet powerful with an useful client/server interface. Requires a 2.6
537	kernel.	508	kernel. Doesn't seem to be maintained anymore and will be removed from
		509	Portage in the near future.
538	</ti>	510	</ti>
539	</tr>	511	</tr>
540	<tr>	512	<tr>
541	<ti><uri link="http://cpuspeedy.sourceforge.net/">gtk-cpuspeedy</uri></ti>	513	<ti><uri link="http://cpuspeedy.sourceforge.net/">gtk-cpuspeedy</uri></ti>
542	<ti>Graphical</ti>	514	<ti>Graphical</ti>
543	<ti>None</ti>	515	<ti>None</ti>
544	<ti>None</ti>	516	<ti>None</ti>
545	<ti>None</ti>	517	<ti>None</ti>
546	<ti>	518	<ti>
547	Gnome application, a graphical tool to set CPU frequency manually. It does	519	Gnome application, a graphical tool to set CPU frequency manually. It does
548	not offer any automation and is mainly listed for the sake of completeness.	520	not offer any automation.
549	</ti>	521	</ti>
550	</tr>	522	</tr>
551	<tr>	523	<tr>
552	<ti>klaptopdaemon</ti>	524	<ti>klaptopdaemon</ti>
553	<ti>Graphical</ti>	525	<ti>Graphical</ti>
…		…
566	two frequencies all the time or wasting energy when setting frequency to an	538	two frequencies all the time or wasting energy when setting frequency to an
567	unnecessary high level.	539	unnecessary high level.
568	</p>	540	</p>
569		541
570	<p>	542	<p>
571	Which one to choose? If you have no idea about it, first try <c>speedfreq</c>:	543	Which one to choose? If you have no idea about it, try <c>cpufreqd</c>:
572	</p>
573
574	<pre caption="Installing speedfreq">
575	# <i>emerge speedfreq</i>
576	# <i>rc-update add speedfreq battery</i>
577	</pre>
578
579	<p>	544	</p>
580	<c>speedfreq</c> can be configured by editing
581	<path>/etc/conf.d/speedfreq</path>. For example, if you like users to be able
582	to change the policy, modify <c>SPEEDFREQ_OPTS=""</c> to
583	<c>SPEEDFREQ_OPTS="-u"</c>. Having done your changes, start the daemon.
584	</p>
585
586	<pre caption="Starting speedfreq">
587	# <i>/etc/init.d/speedfreq start</i>
588	</pre>
589
590	<p>
591	Setting up cpufreqd is a little bit more complicated.
592	</p>
593
594	<warn>
595	Do not run more than one of the above programs at the same time. It may cause
596	confusion like switching between two frequencies all the time. If you just
597	installed speedfreq, skip cpufreqd now.
598	</warn>
599		545
600	<pre caption="Installing cpufreqd">	546	<pre caption="Installing cpufreqd">
601	# <i>emerge cpufreqd</i>	547	# <i>emerge cpufreqd</i>
602	# <i>rc-update add cpufreqd battery</i>
603	</pre>	548	</pre>
604		549
605	<p>
606	<c>cpufreqd</c> comes with a default configuration in
607	<path>/etc/cpufreqd.conf</path>.
608	Change the config file to fit your needs. The following will save more energy
609	than the default one - at the cost of less performance, of course.
610	</p>	550	<p>
		551	<c>cpufreqd</c> can be configured by editing <path>/etc/cpufreqd.conf</path>.
		552	The default one that ships with cpufreqd may look a bit confusing. I recommend
		553	replacing it with the one from Gentoo developer Henrik Brix Andersen (see
		554	below).
		555	</p>
611		556
612	<pre caption="A sample cpufreqd config file">	557	<pre caption="/etc/cpufreqd.conf">
613	[General]	558	[General]
614	pidfile=/var/run/cpufreqd.pid	559	pidfile=/var/run/cpufreqd.pid
615	poll_interval=2	560	poll_interval=2
616	pm_type=acpi	561	pm_type=acpi
617	<comment># Uncomment the following line to enable ACPI workaround (see cpufreqd.conf(5))	562	verbosity=5
618	# acpi_workaround=1</comment>
619	verbosity=4 <comment>#(if you want a minimal logging set to 5)</comment>
620		563
621	<comment># Full performance</comment>
622	[Profile]	564	[Profile]
		565	name=ondemand
		566	minfreq=0%
		567	maxfreq=100%
		568	policy=ondemand
		569
		570	[Profile]
		571	name=powersave
		572	minfreq=0%
		573	maxfreq=100%
		574	policy=powersave
		575
		576	[Profile]
		577	name=performance
		578	minfreq=0%
		579	maxfreq=100%
		580	policy=performance
		581
		582	[Rule]
		583	name=battery
		584	ac=off
		585	profile=ondemand
		586
		587	[Rule]
		588	name=battery_low
		589	ac=off
		590	battery_interval=0-10
		591	profile=powersave
		592
		593	[Rule]
623	name=ac	594	name=ac
		595	ac=on
		596	profile=performance
		597	</pre>
		598
		599	<p>
		600	You can't use a percentage value like above for min_freq and max_freq if you
		601	are using kernel 2.6 with the sysfs interface (you probably do). Replace it
		602	with the lowest and highest frequency as reported by <c>cpufreq-info
		603	--hwlimits</c>. For example, on my 1.4 GHz Pentium M I put in
		604	</p>
		605
		606	<pre caption="Sample values for minfreq and maxfreq">
624	minfreq=600000	607	minfreq=600000
625	maxfreq=1400000	608	maxfreq=1400000
626	policy=performance
627
628	<comment># Maximum power saving</comment>
629	[Profile]
630	name=battery
631	minfreq=600000
632	maxfreq=900000
633	policy=powersave
634
635	<comment># Constant frequency</comment>
636	[Profile]
637	name=dvd
638	minfreq=900000
639	maxfreq=1100000
640	policy=powersave
641
642	<comment># Full performance when running on AC</comment>
643	[Rule]
644	name=ac_on
645	ac=on
646	profile=ac
647
648	<comment># Compiling should be fast if battery state is ok</comment>
649	[Rule]
650	name=compiling
651	ac=off
652	battery_interval=30-100
653	programs=emerge,make,gcc,cpp
654	cpu_interval=0-100
655	profile=ac
656
657	<comment># watching DVD's gets sluggish with slow CPU frequency
658	# Can also be used for games etc.</comment>
659	[Rule]
660	name=dvd_watching
661	ac=off
662	battery_interval=15-100
663	programs=xine,mplayer,avidemux,kaffeine,kmplayer
664	cpu_interval=0-100
665	profile=dvd
666
667	<comment># If above doesn't apply, maximise power saving</comment>
668	[Rule]
669	name=battery_on
670	ac=off
671	battery_interval=0-100
672	cpu_interval=0-100
673	profile=battery
674	</pre>	609	</pre>
675		610
676	<p>
677	<c>cpudyn</c> and <c>powernowd</c> are installed in the same way as
678	<c>speedfreq</c>.
679	</p>	611	<p>
		612	Last not least start the daemon.
		613	</p>
		614
		615	<pre caption="Starting cpufreqd">
		616	# <i>rc-update add cpufreqd default battery</i>
		617	# <i>rc</i>
		618	</pre>
		619
		620	<warn>
		621	Do not run more than one of the above programs at the same time. It may cause
		622	confusion like switching between two frequencies all the time.
		623	</warn>
680		624
681	</body>	625	</body>
682	</section>	626	</section>
683		627
684	<section>	628	<section>
…		…
690	The last thing to check is that your new policies do a good job. An easy way to	634	The last thing to check is that your new policies do a good job. An easy way to
691	do so is monitoring CPU speed while working with your laptop:	635	do so is monitoring CPU speed while working with your laptop:
692	</p>	636	</p>
693		637
694	<pre caption="Monitoring CPU speed">	638	<pre caption="Monitoring CPU speed">
695	# <i>watch -n 1 'grep "cpu MHz" /proc/cpuinfo'</i>	639	# <i>watch grep "cpu MHz" /proc/cpuinfo</i>
696	</pre>	640	</pre>
697		641
698	<p>	642	<p>
699	If <path>/proc/cpuinfo</path> doesn't get updated (see above), monitor the CPU	643	If <path>/proc/cpuinfo</path> doesn't get updated (see Troubleshooting),
700	frequency with:	644	monitor the CPU frequency with:
701	</p>	645	</p>
702		646
703	<pre caption="Alternative CPU speed monitoring">	647	<pre caption="Alternative CPU speed monitoring">
704	# <i>watch -n 1 x86info -mhz</i>	648	# <i>watch x86info -mhz</i>
705	</pre>	649	</pre>
706		650
707	<p>	651	<p>
708	Depending on your setup, CPU speed should increase on heavy load, decrease on	652	Depending on your setup, CPU speed should increase on heavy load, decrease on
709	no activity or just stay at the same level.	653	no activity or just stay at the same level. When using cpufreqd and verbosity
		654	set to 5 or higher in <path>cpufreqd.conf</path> you'll get additional
		655	information about what's happening reported to syslog.
710	</p>	656	</p>
711		657
712	</body>	658	</body>
713	</section>	659	</section>
714	</chapter>	660	</chapter>
…		…
761	</p>	707	</p>
762		708
763	<p>	709	<p>
764	Probably more important is the backlight dimming. If you have access to the	710	Probably more important is the backlight dimming. If you have access to the
765	dimming settings via a tool, write a small script that dims the backlight in	711	dimming settings via a tool, write a small script that dims the backlight in
766	battery mode and place it in your <e>battery</e> runlevel.	712	battery mode and place it in your <e>battery</e> runlevel. The following script
		713	should work on most IBM Thinkpads. It needs the <c>app-laptop/ibm-acpi</c>
		714	package or the appropriate option in your kernel has to be enabled.
		715	</p>
		716
		717	<warn>
		718	Support for setting brightness is marked experimental in ibm-acpi. It accesses
		719	hardware directly and may cause severe harm to your system. Please read the
		720	<uri link="http://ibm-acpi.sourceforge.net/">ibm-acpi website</uri>
		721	</warn>
		722
767	</p>	723	<p>
		724	To be able to set the brightness level, the ibm_acpi module has to be loaded
		725	with the experimental parameter.
		726	</p>
		727
		728	<pre caption="automatically loading the ibm_acpi module">
		729	<comment>(Please read the warnings above before doing this!)</comment>
		730	<i># emerge ibm-acpi</i>
		731	<i># echo "options ibm_acpi experimental=1" >> /etc/modules.d/ibm_acpi</i>
		732	<i># /sbin/modules-update</i>
		733	<i># echo ibm_acpi >> /etc/modules.autoload.d/kernel-2.6</i>
		734	<i># modprobe ibm_acpi</i>
		735	</pre>
		736
		737	<p>
		738	This should work without error messages and a file
		739	<path>/proc/acpi/ibm/brightness</path> should be created after loading the
		740	module. An init script will take care of choosing the brightness according
		741	to the power source.
		742	</p>
		743
		744	<pre caption="/etc/conf.d/lcd-brightness">
		745	<comment># See /proc/acpi/ibm/brightness for available values</comment>
		746	<comment># Please read /usr/share/doc/ibm-acpi-*/README.gz</comment>
		747
		748	<comment># brigthness level in ac mode. Default is 7.</comment>
		749	BRIGHTNESS_AC=7
		750
		751	<comment># brightness level in battery mode. Default is 4.</comment>
		752	BRIGHTNESS_BATTERY=4
		753	</pre>
		754
		755	<pre caption="/etc/init.d/lcd-brightness">
		756	#!/sbin/runscript
		757
		758	set_brightness() {
		759	if on_ac_power
		760	then
		761	LEVEL=${BRIGHTNESS_AC:-7}
		762	else
		763	LEVEL=${BRIGHTNESS_BATTERY:-4}
		764	fi
		765
		766	if [ -f /proc/acpi/ibm/brightness ]
		767	then
		768	ebegin "Setting LCD brightness"
		769	echo "level ${LEVEL}" > /proc/acpi/ibm/brightness
		770	eend $?
		771	else
		772	ewarn "Setting LCD brightness is not supported."
		773	ewarn "Check that ibm_acpi is loaded into the kernel"
		774	fi
		775	}
		776
		777	start() {
		778	set_brightness
		779	}
		780
		781	stop () {
		782	set_brightness
		783	}
		784	</pre>
		785
		786	<p>
		787	When done, make sure brightness is adjusted automatically by adding it to the
		788	battery runlevel.
		789	</p>
		790
		791	<pre caption="Enabling automatic brightness adjustment">
		792	<i># chmod +x /etc/init.d/lcd-brightness</i>
		793	<i># rc-update add lcd-brightness battery</i>
		794	<i># rc</i>
		795	</pre>
768		796
769	</body>	797	</body>
770	</section>	798	</section>
771	</chapter>	799	</chapter>
772		800
…		…
809	<path>/etc/init.d/pm.hda</path> like this:	837	<path>/etc/init.d/pm.hda</path> like this:
810	</p>	838	</p>
811		839
812	<pre caption="Using hdparm for disk standby">	840	<pre caption="Using hdparm for disk standby">
813	#!/sbin/runscript	841	#!/sbin/runscript
		842
		843	depend() {
		844	after hdparm
		845	}
		846
814	start() {	847	start() {
815	ebegin "Activating Power Management for Hard Drives"	848	ebegin "Activating Power Management for Hard Drives"
816	hdparm -q -S12 /dev/hda	849	hdparm -q -S12 /dev/hda
817	eend $?	850	eend $?
818	}	851	}
…		…
851	include the so-called <e>laptop-mode</e>. When activated, dirty buffers are	884	include the so-called <e>laptop-mode</e>. When activated, dirty buffers are
852	written to disk on read calls or after 10 minutes (instead of 30 seconds). This	885	written to disk on read calls or after 10 minutes (instead of 30 seconds). This
853	minimizes the time the hard disk needs to be spun up.	886	minimizes the time the hard disk needs to be spun up.
854	</p>	887	</p>
855		888
856	<p>
857	<!-- TODO: bug #45593 -->
858	Besides kernel support you also need a script that controls starting and
859	stopping of laptop-mode. You kernel documentation in
860	<path>/usr/src/linux/Documentation/laptop-mode.txt</path> contains one as well
861	as the package <c>laptop-mode-tools</c>. None of them is easy to install
862	though.
863	</p>
864
865	<p>
866	Ebuilds for laptop-mode-tools are not in Portage, because Gentoo developers
867	don't think they are production ready yet. Take that into consideration
868	before using the ebuilds which can be found in <uri
869	link="http://bugs.gentoo.org/show_bug.cgi?id=45593">Bugzilla</uri>. The Gentoo
870	Handbook tells you how to use external ebuilds if you don't know where to put
871	them. Once your PORTDIR_OVERLAY contains the ebuilds, install the
872	script:
873	</p>
874
875	<warn>
876	This package is not seen as production ready and installing custom ebuilds from
877	Bugzilla is not recommended. Please don't use laptop-mode-tools if you're
878	unsure.
879	</warn>
880
881	<pre caption="Automated start of laptop-mode">	889	<pre caption="Automated start of laptop-mode">
882	# <i>emerge laptop-mode-tools</i>	890	# <i>emerge laptop-mode-tools</i>
883	</pre>	891	</pre>
884		892
885	<p>	893	<p>
886	<c>laptop-mode-tools</c> has it's configuration file in	894	<c>laptop-mode-tools</c> has it's configuration file in
887	<path>/etc/laptop-mode/laptop-mode.conf</path>. Adjust it the way you like it,	895	<path>/etc/laptop-mode/laptop-mode.conf</path>. Adjust it the way you like it,
888	it's well commented. If you have <e>apm</e> or <e>acpi</e> in your USE flags,	896	it's well commented. Run <c>rc-update add laptop_mode battery</c> to start it
889	laptop-mode will be started automatically in battery mode. Otherwise you can	897	automatically.
890	automate it by running <c>rc-update add laptop-mode battery</c>.
891	</p>	898	</p>
892		899
893	</body>	900	</body>
894	</section>	901	</section>
895	<section>	902	<section>

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