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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 1.15 2005/10/28 14:48:06 so Exp $ --> 3<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/power-management-guide.xml,v 1.30 2007/07/24 22:32:59 nightmorph Exp $ -->
4<guide link="/doc/en/power-management-guide.xml"> 4<guide link="/doc/en/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="earthwings@gentoo.org">Dennis Nienhüser</mail>
9</author>
10<author title="Editor">
11 <mail link="chriswhite@gentoo.org">Chris White</mail>
12</author>
13<author title="Editor">
14 <mail link="nightmorph@gentoo.org">Joshua Saddler</mail>
9</author> 15</author>
10 16
11<abstract> 17<abstract>
12Power Management is the key to extend battery run time on mobile systems like 18Power Management is the key to extend battery run time on mobile systems like
13laptops. This guide assists you setting it up on your laptop. 19laptops. This guide assists you setting it up on your laptop.
15 21
16<!-- The content of this document is licensed under the CC-BY-SA license --> 22<!-- The content of this document is licensed under the CC-BY-SA license -->
17<!-- See http://creativecommons.org/licenses/by-sa/2.5 --> 23<!-- See http://creativecommons.org/licenses/by-sa/2.5 -->
18<license/> 24<license/>
19 25
20<version>1.25</version> 26<version>1.35</version>
21<date>2005-10-02</date> 27<date>2007-07-24</date>
22 28
23<chapter> 29<chapter>
24<title>Introduction</title> 30<title>Introduction</title>
25<section> 31<section>
26<title>Why Power Management?</title>
27<body> 32<body>
28 33
29<p> 34<p>
30Capacity and lifetime of laptop batteries have improved much in the last years. 35Capacity and lifetime of laptop batteries have improved much in the last years.
31Nevertheless modern processors consume much more energy than older ones and 36Nevertheless modern processors consume much more energy than older ones and
35intelligent Power Management policies. 40intelligent Power Management policies.
36</p> 41</p>
37 42
38</body> 43</body>
39</section> 44</section>
40
41<section> 45<section>
42<title>A quick overview</title> 46<title>A Quick Overview</title>
43<body> 47<body>
44 48
45<p> 49<p>
46Please notice that this guide describes Power Management for <e>laptops</e>. 50Please notice that this guide describes Power Management for <e>laptops</e>.
47While some sections might also suite for <e>servers</e>, others do not and may 51While some sections might also suite for <e>servers</e>, others do not and may
53As this guide has become rather long, here's a short overview helping you to 57As this guide has become rather long, here's a short overview helping you to
54find your way through it. 58find your way through it.
55</p> 59</p>
56 60
57<p> 61<p>
58The <e>Prerequisites</e> chapter talks about some requirements that should be 62The <uri link="#doc_chap2">Prerequisites</uri> chapter talks about some
59met before any of the following device individual sections will work. This 63requirements that should be met before any of the following device individual
60includes BIOS settings, kernel configuration and some simplifications in user 64sections will work. This includes BIOS settings, kernel configuration and some
61land. The following three chapters focus on devices that typically consume 65simplifications in user land. The following three chapters focus on devices
62most energy - processor, display and hard drive. Each can be configured 66that typically consume most energy - processor, display and hard drive. Each
63seperately. <e>CPU Power Management</e> shows how to adjust the processor's 67can be configured seperately. <uri link="#doc_chap3">CPU Power Management</uri>
64frequency to save a maximum of energy whithout losing too much performance. A 68shows how to adjust the processor's frequency to save a maximum of energy
65few different tricks prevent your hard drive from working unnecessarily often 69without losing too much performance. A few different tricks prevent your hard
66in <e>Disk Power Management</e> (decreasing noise level as a nice side 70drive from working unnecessarily often in <uri link="#doc_chap5">Disk Power
67effect). Some notes on graphics cards, Wireless LAN and USB finish the device 71Management</uri> (decreasing noise level as a nice side effect). Some notes on
68section in <e>Power Management for other devices</e> while another chapter is 72graphics cards, Wireless LAN and USB finish the device section in <uri
69dedicated to the (rather experimental) <e>sleep states</e>. Last not least 73link="#doc_chap6">Power Management For Other Devices</uri> while another
70<e>Troubleshooting</e> lists common pitfalls. 74chapter is dedicated to the (rather experimental) <uri link="#doc_chap7">sleep
75states</uri>. Last not least <uri link="#doc_chap8">Troubleshooting</uri> lists
76common pitfalls.
71</p> 77</p>
72 78
73</body> 79</body>
74</section>
75
76<section> 80</section>
81<section>
77<title>Power Budget for each component</title> 82<title>Power Budget For Each Component</title>
78<body> 83<body>
79 84
80<figure link="/images/energy-budget.png" short="Which component consumes how 85<figure link="/images/energy-budget.png" short="Which component consumes how
81much energy?" caption="Power budget for each component"/> 86much energy?" caption="Power budget for each component"/>
82 87
93</chapter> 98</chapter>
94 99
95<chapter> 100<chapter>
96<title>Prerequisites</title> 101<title>Prerequisites</title>
97<section> 102<section>
98<title>What has to be done first</title>
99<body>
100
101<p>
102Before going into the details on making individual devices Power Management
103aware, make sure certain requirements are met. After controlling the BIOS
104settings, some kernel options want to be enabled - these are in short ACPI,
105sleep states and CPU frequency scaling. As power saving most of the time comes
106along with performance loss or increased latency, it should only be enabled
107when running on batteries. That's where a new runlevel <e>battery</e> comes in
108handy.
109</p>
110
111</body> 103<body>
112</section> 104
105<p>
106Before discussing the details of making individual devices Power Management
107aware, make sure certain requirements are met. After controlling BIOS settings,
108some kernel options want to be enabled - these are in short ACPI, sleep states
109and CPU frequency scaling. As power saving most of the time comes along with
110performance loss or increased latency, it should only be enabled when running
111on batteries. That's where a new runlevel <e>battery</e> comes in handy.
112</p>
113
114</body>
113<section> 115</section>
116<section>
114<title>The BIOS part</title> 117<title>The BIOS Part</title>
115<body> 118<body>
116 119
117<p> 120<p>
118First have a look into your BIOS Power Management settings. The best way is to 121First have a look into your BIOS Power Management settings. The best way is to
119combine BIOS and operating system policies, but for the moment it's better to 122combine BIOS and operating system policies, but for the moment it's better to
123</p> 126</p>
124 127
125</body> 128</body>
126</section> 129</section>
127<section> 130<section>
131<title>Setting USE Flags</title>
132<body>
133
134<p>
135Please check that the <c>acpi</c> USE flag is set in
136<path>/etc/make.conf</path>. Other USE flags that might be interesting for your
137system are <c>apm</c>, <c>lm_sensors</c>, <c>nforce2</c>, <c>nvidia</c>,
138<c>pmu</c>. See <path>/usr/portage/profiles/use*.desc</path> for details. If
139you forgot to set one of these flags, you can recompile affected packages using
140the <c>--newuse</c> flag in <c>emerge</c>, see <c>man emerge</c>.
141</p>
142
143</body>
144</section>
145<section>
128<title>Configuring the kernel</title> 146<title>Configuring The Kernel</title>
129<body> 147<body>
130 148
131<p> 149<p>
132ACPI (Advanced Configuration and Power Interface) support in the kernel is 150ACPI (Advanced Configuration and Power Interface) support in the kernel is
133still work in progress. Using a recent kernel will make sure you'll get the 151still work in progress. Using a recent kernel will make sure you'll get the
134most out of it. 152most out of it.
135</p> 153</p>
136 154
137<p> 155<p>
138There are different kernel sources in Portage. I'd recommend using 156There are different kernel sources in Portage. I'd recommend using
139<c>gentoo-sources</c> or <c>suspend2-sources</c>. The latter contains patches 157<c>gentoo-sources</c> or <c>suspend2-sources</c>. The latter contains patches
140for Software Suspend 2, see the chapter about sleep states for details. When 158for Software Suspend 2, see the chapter about <uri link="#doc_chap7">sleep
141configuring the kernel, activate at least these options: 159states</uri> for more details. When configuring the kernel, activate at least
160these options:
142</p> 161</p>
143 162
144<pre caption="Minimum kernel setup for Power Management (Kernel 2.6)"> 163<pre caption="Minimum kernel setup for Power Management (Kernel 2.6)">
145Power Management Options ---&gt; 164Power Management Options ---&gt;
146 [*] Power Management Support 165 [*] Power Management Support
163 &lt; &gt; Toshiba Laptop Extras 182 &lt; &gt; Toshiba Laptop Extras
164 (0) Disable ACPI for systems before Jan 1st this year 183 (0) Disable ACPI for systems before Jan 1st this year
165 [ ] Debug Statements 184 [ ] Debug Statements
166 [*] Power Management Timer Support 185 [*] Power Management Timer Support
167 &lt; &gt; ACPI0004,PNP0A05 and PNP0A06 Container Driver (EXPERIMENTAL) 186 &lt; &gt; ACPI0004,PNP0A05 and PNP0A06 Container Driver (EXPERIMENTAL)
168 187
169 CPU Frequency Scaling ---&gt; 188 CPU Frequency Scaling ---&gt;
170 [*] CPU Frequency scaling 189 [*] CPU Frequency scaling
171 [ ] Enable CPUfreq debugging 190 [ ] Enable CPUfreq debugging
172 &lt; &gt; CPU frequency translation statistics 191 &lt; &gt; CPU frequency translation statistics
173 [ ] CPU frequency translation statistics details 192 [ ] CPU frequency translation statistics details
186(see below). If you own an ASUS, Medion, IBM Thinkpad or Toshiba laptop, enable 205(see below). If you own an ASUS, Medion, IBM Thinkpad or Toshiba laptop, enable
187the appropriate section. 206the appropriate section.
188</p> 207</p>
189 208
190<p> 209<p>
191The kernel has to know how to enable CPU frequency scaling on your processor. As 210The kernel has to know how to enable CPU frequency scaling on your processor.
192each type of CPU has a different interface, you've got to choose the right 211As each type of CPU has a different interface, you've got to choose the right
193driver for your processor. Be careful here - enabling <e>Intel Pentium 4 clock 212driver for your processor. Be careful here - enabling <c>Intel Pentium 4 clock
194modulation</e> on a Pentium M system will lead to strange results for example. 213modulation</c> on a Pentium M system will lead to strange results for example.
195Consult the kernel documentation if you're unsure which one to take. 214Consult the kernel documentation if you're unsure which one to take.
196</p> 215</p>
197 216
198<p> 217<p>
199Compile your kernel, make sure the right modules get loaded at startup and boot 218Compile your kernel, make sure the right modules get loaded at startup and boot
200into your new ACPI-enabled kernel. Next run <c>emerge sys-power/acpid</c> to get 219into your new ACPI-enabled kernel. Next run <c>emerge sys-power/acpid</c> to
201the acpi daemon. This one informs you about events like switching from AC to 220get the acpi daemon. This one informs you about events like switching from AC
202battery or closing the lid. Make sure the modules are loaded if you didn't 221to battery or closing the lid. Make sure the modules are loaded if you didn't
203compile them into the kernel and start acpid by executing 222compile them into the kernel and start acpid by executing <c>/etc/init.d/acpid
204<c>/etc/init.d/acpid start</c>. Run <c>rc-update add acpid default</c> to load 223start</c>. Run <c>rc-update add acpid default</c> to load it on startup. You'll
205it on startup. You'll soon see how to use it. 224soon see how to use it.
206</p> 225</p>
207 226
208<pre caption="Installing acpid"> 227<pre caption="Installing acpid">
209# <i>emerge sys-power/acpid</i> 228# <i>emerge sys-power/acpid</i>
210# <i>/etc/init.d/acpid start</i> 229# <i>/etc/init.d/acpid start</i>
212</pre> 231</pre>
213 232
214</body> 233</body>
215</section> 234</section>
216<section> 235<section>
217<title>Creating a "battery" runlevel</title> 236<title>Creating A "battery" Runlevel</title>
218<body> 237<body>
219 238
220<p> 239<p>
221The default policy will be to enable Power Management only when needed - 240The default policy will be to enable Power Management only when needed -
222running on batteries. To make the switch between AC and battery convenient, 241running on batteries. To make the switch between AC and battery convenient,
223create a runlevel <e>battery</e> that holds all the scripts starting and 242create a runlevel <c>battery</c> that holds all the scripts starting and
224stopping Power Management. 243stopping Power Management.
225</p> 244</p>
226 245
227<note> 246<note>
228You can safely skip this section if you don't like the idea of having another 247You can safely skip this section if you don't like the idea of having another
229runlevel. However, skipping this step will make the rest a bit trickier to set 248runlevel. However, skipping this step will make the rest a bit trickier to set
230up. The next sections assume a runlevel <e>battery</e> exists. 249up. The next sections assume a runlevel <c>battery</c> exists.
231</note> 250</note>
232 251
233<pre caption="Creating a battery runlevel"> 252<pre caption="Creating a battery runlevel">
234# <i>cd /etc/runlevels</i> 253# <i>cd /etc/runlevels</i>
235# <i>cp -a default battery</i> 254# <i>cp -a default battery</i>
236</pre> 255</pre>
237 256
238<p> 257<p>
239Finished. Your new runlevel <e>battery</e> contains everything like 258Finished. Your new runlevel <c>battery</c> contains everything like
240<e>default</e>, but there is no automatic switch between both yet. Time to 259<c>default</c>, but there is no automatic switch between both yet. Time to
241change it. 260change it.
242</p> 261</p>
243 262
244</body> 263</body>
245</section> 264</section>
246<section> 265<section>
247<title>Reacting on ACPI events</title> 266<title>Reacting On ACPI Events</title>
248<body> 267<body>
249 268
250<p> 269<p>
251Typical ACPI events are closing the lid, changing the power source or pressing 270Typical ACPI events are closing the lid, changing the power source or pressing
252the sleep button. An important event is changing the power source, which should 271the sleep button. An important event is changing the power source, which should
259<c>on_ac_power</c> command from <c>sys-power/powermgmt-base</c> - make sure the 278<c>on_ac_power</c> command from <c>sys-power/powermgmt-base</c> - make sure the
260package is installed on your system. 279package is installed on your system.
261</p> 280</p>
262 281
263<pre caption="Installing powermgt-base"> 282<pre caption="Installing powermgt-base">
264<i># emerge powermgmt-base</i> 283# <i>emerge powermgmt-base</i>
265</pre> 284</pre>
266 285
267<p> 286<p>
268You are now able to determine the power source by executing 287You are now able to determine the power source by executing <c>on_ac_power
269<c>on_ac_power &amp;&amp; echo AC available || echo Running on batteries</c> in 288&amp;&amp; echo AC available || echo Running on batteries</c> in a shell. The
270a shell. The script below is responsible for changing runlevels. Save it as 289script below is responsible for changing runlevels. Save it as
271<path>/etc/acpi/actions/pmg_switch_runlevel.sh</path>. 290<path>/etc/acpi/actions/pmg_switch_runlevel.sh</path>.
272</p> 291</p>
273 292
274<pre caption="/etc/acpi/actions/pmg_switch_runlevel.sh"> 293<pre caption="/etc/acpi/actions/pmg_switch_runlevel.sh">
275#!/bin/bash 294#!/bin/bash
280<comment># END configuration</comment> 299<comment># END configuration</comment>
281 300
282 301
283if [ ! -d "/etc/runlevels/${RUNLEVEL_AC}" ] 302if [ ! -d "/etc/runlevels/${RUNLEVEL_AC}" ]
284then 303then
285 logger "${0}: Runlevel ${RUNLEVEL_AC} does not exist. Aborting." 304 logger "${0}: Runlevel ${RUNLEVEL_AC} does not exist. Aborting."
286 exit 1 305 exit 1
287fi 306fi
288 307
289if [ ! -d "/etc/runlevels/${RUNLEVEL_BATTERY}" ] 308if [ ! -d "/etc/runlevels/${RUNLEVEL_BATTERY}" ]
290then 309then
291 logger "${0}: Runlevel ${RUNLEVEL_BATTERY} does not exist. Aborting." 310 logger "${0}: Runlevel ${RUNLEVEL_BATTERY} does not exist. Aborting."
292 exit 1 311 exit 1
293fi 312fi
294 313
295if on_ac_power 314if on_ac_power
296then 315then
297 if [[ "$(cat /var/lib/init.d/softlevel)" != "${RUNLEVEL_AC}" ]] 316 if [[ "$(&lt;/var/lib/init.d/softlevel)" != "${RUNLEVEL_AC}" ]]
298 then 317 then
299 logger "Switching to ${RUNLEVEL_AC} runlevel" 318 logger "Switching to ${RUNLEVEL_AC} runlevel"
300 /sbin/rc ${RUNLEVEL_AC} 319 /sbin/rc ${RUNLEVEL_AC}
301 fi 320 fi
302elif [[ "$(cat /var/lib/init.d/softlevel)" != "${RUNLEVEL_BATTERY}" ]] 321elif [[ "$(&lt;/var/lib/init.d/softlevel)" != "${RUNLEVEL_BATTERY}" ]]
303then 322then
304 logger "Switching to ${RUNLEVEL_BATTERY} runlevel" 323 logger "Switching to ${RUNLEVEL_BATTERY} runlevel"
305 /sbin/rc ${RUNLEVEL_BATTERY} 324 /sbin/rc ${RUNLEVEL_BATTERY}
306fi 325fi
307</pre> 326</pre>
308 327
309<p> 328<p>
310Dont forget to run <c>chmod +x /etc/acpi/actions/pmg_switch_runlevel.sh</c> to 329Dont forget to run <c>chmod +x /etc/acpi/actions/pmg_switch_runlevel.sh</c> to
311make the script executable. The last thing that needs to be done is calling the 330make the script executable. The last thing that needs to be done is calling the
312script whenever the power source changes. That's done by catching ACPI events 331script whenever the power source changes. That's done by catching ACPI events
313with the help of <c>acpid</c>. First you need to know which events are 332with the help of <c>acpid</c>. First you need to know which events are
314generated when the power source changes. The events are called 333generated when the power source changes. The events are called
315<e>ac_adapter</e> and <e>battery</e> on most laptops, but it might be different 334<c>ac_adapter</c> and <c>battery</c> on most laptops, but it might be different
316on yours. 335on yours.
317</p> 336</p>
318 337
319<pre caption="Determining ACPI events for changing the power source"> 338<pre caption="Determining ACPI events for changing the power source">
320<i># tail -f /var/log/acpid | grep "received event"</i> 339# <i>tail -f /var/log/acpid | grep "received event"</i>
321</pre> 340</pre>
322 341
323<p> 342<p>
324Run the command above and pull the power cable. You should see something 343Run the command above and pull the power cable. You should see something like
325like this: 344this:
326</p> 345</p>
327 346
328<pre caption="Sample output for power source changes"> 347<pre caption="Sample output for power source changes">
329[Tue Sep 20 17:39:06 2005] received event "ac_adapter AC 00000080 00000000" 348[Tue Sep 20 17:39:06 2005] received event "ac_adapter AC 00000080 00000000"
330[Tue Sep 20 17:39:06 2005] received event "battery BAT0 00000080 00000001" 349[Tue Sep 20 17:39:06 2005] received event "battery BAT0 00000080 00000001"
331</pre> 350</pre>
332 351
333<p> 352<p>
334The interesting part is the quoted string after <e>received event</e>. It will 353The interesting part is the quoted string after <c>received event</c>. It will
335be matched by the event line in the files you are going to create below. Don't 354be matched by the event line in the files you are going to create below. Don't
336worry if your system generates multiple events or always the same. As long as 355worry if your system generates multiple events or always the same. As long as
337any event is generated, runlevel changing will work. 356any event is generated, runlevel changing will work.
338</p> 357</p>
339 358
354<p> 373<p>
355Finally acpid has to be restarted to recognize the changes. 374Finally acpid has to be restarted to recognize the changes.
356</p> 375</p>
357 376
358<pre caption="Finishing runlevel switching with acpid"> 377<pre caption="Finishing runlevel switching with acpid">
359<i># /etc/init.d/acpid restart</i> 378# <i>/etc/init.d/acpid restart</i>
360</pre> 379</pre>
361 380
362<p> 381<p>
363Give it a try: Plug AC in and out and watch syslog for the "Switching to AC 382Give it a try: Plug AC in and out and watch syslog for the "Switching to AC
364mode" or "Switching to battery mode" messages. See the Troubleshooting 383mode" or "Switching to battery mode" messages. See the <uri
365section if the script is not able to detect the power source correctly. 384link="#doc_chap8">Troubleshooting section</uri> if the script is not able to
385detect the power source correctly.
366</p> 386</p>
367 387
368<p> 388<p>
369Due to the nature of the event mechanism, your laptop will boot into runlevel 389Due to the nature of the event mechanism, your laptop will boot into runlevel
370<e>default</e> regardless of the AC/battery state. This is fine when running 390<c>default</c> regardless of the AC/battery state. This is fine when running
371from AC, but we'd like to boot into the battery runlevel otherwise. One 391from AC, but we'd like to boot into the battery runlevel otherwise. One
372solution would be to add another entry to the boot loader with the parameter 392solution would be to add another entry to the boot loader with the parameter
373<c>softlevel=battery</c>, but it's likely to forget choosing it. A better way 393<c>softlevel=battery</c>, but it's likely to forget choosing it. A better way
374is faking an ACPI event in the end of the boot process and letting 394is faking an ACPI event in the end of the boot process and letting
375<path>pmg_switch_runlevel.sh</path> script decide whether a 395<path>pmg_switch_runlevel.sh</path> script decide whether a runlevel change is
376runlevel change is necessary. Open <path>/etc/conf.d/local.start</path> in your 396necessary. Open <path>/etc/conf.d/local.start</path> in your favourite editor
377favourite editor and add these lines: 397and add these lines:
378</p> 398</p>
379 399
380<pre caption="Runlevel adjustment at boot time by editing local.start"> 400<pre caption="Runlevel adjustment at boot time by editing local.start">
381<comment># Fake acpi event to switch runlevel if running on batteries</comment> 401<comment># Fake acpi event to switch runlevel if running on batteries</comment>
382/etc/acpi/actions/pmg_switch_runlevel.sh "battery/battery" 402/etc/acpi/actions/pmg_switch_runlevel.sh "battery/battery"
383</pre> 403</pre>
384 404
385<p> 405<p>
386Prepared like this you can activate Power Management policies for individual 406Prepared like this you can activate Power Management policies for individual
387devices. 407devices.
388</p> 408</p>
389 409
390</body> 410</body>
391</section> 411</section>
392</chapter> 412</chapter>
393 413
394<chapter> 414<chapter>
395<title>CPU Power Management</title> 415<title>CPU Power Management</title>
396<section> 416<section>
417<body>
418
419<p>
420Mobile processors can operate at different frequencies. Some allow changing
421voltage as well. Most of the time your CPU doesn't need to run at full speed
422and scaling it down will save much energy - often without any performance
423decrease.
424</p>
425
426</body>
427</section>
428<section>
397<title>Some technical terms</title> 429<title>Some Technical Terms</title>
398<body> 430<body>
399 431
400<p> 432<p>
401CPU frequency scaling brings up some technical terms that might be unknown to 433CPU frequency scaling brings up some technical terms that might be unknown to
402you. Here's a quick introduction. 434you. Here's a quick introduction.
403</p> 435</p>
404 436
405<p> 437<p>
406First of all, the kernel has to be able to change the processor's frequency. 438First of all, the kernel has to be able to change the processor's frequency.
407The <e>CPUfreq processor driver</e> knows the commands to do it on your CPU. 439The <b>CPUfreq processor driver</b> knows the commands to do it on your CPU.
408Thus it's important to choose the right one in your kernel. You should 440Thus it's important to choose the right one in your kernel. You should already
409already have done it above. Once the kernel knows how to change frequencies, 441have done it above. Once the kernel knows how to change frequencies, it has to
410it has to know which frequency it should set. This is done according to the 442know which frequency it should set. This is done according to the <b>policy</b>
411<e>policy</e> which consists of a <e>CPUfreq policy</e> and a 443which consists of a <b>CPUfreq policy</b> and a <b>governor</b>. A CPUfreq
412<e>governor</e>. A CPUfreq policy are just two numbers which define a range 444policy are just two numbers which define a range the frequency has to stay
413the frequency has to stay between - minimal and maximal frequency. The 445between - minimal and maximal frequency. The governor now decides which of the
414governor now decides which of the available frequencies in between minimal 446available frequencies in between minimal and maximal frequency to choose. For
415and maximal frequency to choose. For example, the <e>powersave governor</e> 447example, the <b>powersave governor</b> always chooses the lowest frequency
416always chooses the lowest frequency available, the <e>performance 448available, the <b>performance governor</b> the highest one. The <b>userspace
417governor</e> the highest one. The <e>userspace governor</e> makes no decision 449governor</b> makes no decision but chooses whatever the user (or a program in
418but chooses whatever the user (or a program in userspace) wants - which means 450userspace) wants - which means it reads the frequency from
419it reads the frequency from
420<path>/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed</path>. 451<path>/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed</path>.
421</p> 452</p>
422 453
423<p> 454<p>
424This doesn't sound like dynamic frequency changes yet and in fact it isn't. 455This doesn't sound like dynamic frequency changes yet and in fact it isn't.
425Dynamics however can be accomplished with various approaches. For example, 456Dynamics however can be accomplished with various approaches. For example, the
426the <e>ondemand governor</e> makes its decisions depending on the current CPU 457<b>ondemand governor</b> makes its decisions depending on the current CPU load.
427load. The same is done by various userland tools like <c>cpudyn</c>, 458The same is done by various userland tools like <c>cpudyn</c>, <c>cpufreqd</c>,
428<c>cpufreqd</c>, <c>powernowd</c> and many more. ACPI events can be used to 459<c>powernowd</c> and many more. ACPI events can be used to enable or disable
429enable or disable dynamic frequency changes depending on power source. 460dynamic frequency changes depending on power source.
430</p> 461</p>
431 462
432</body> 463</body>
433</section>
434<section> 464</section>
465<section>
435<title>Setting the frequency manually</title> 466<title>Setting The Frequency Manually</title>
436<body> 467<body>
437 468
438<p> 469<p>
439Decreasing CPU speed and voltage has two advantages: On the one hand less 470Decreasing CPU speed and voltage has two advantages: On the one hand less
440energy is consumed, on the other hand there is thermal improvement as your 471energy is consumed, on the other hand there is thermal improvement as your
443between performance loss and energy saving. 474between performance loss and energy saving.
444</p> 475</p>
445 476
446<note> 477<note>
447Not every laptop supports frequency scaling. If unsure, have a look at the list 478Not every laptop supports frequency scaling. If unsure, have a look at the list
448of supported processors in the <e>Troubleshooting</e> section to verify your's 479of supported processors in the <uri link="#doc_chap8">Troubleshooting</uri>
449is supported. 480section to verify yours is supported.
450</note> 481</note>
451 482
452<p> 483<p>
453It's time to test whether CPU frequency changing works. Let's install another 484It's time to test whether CPU frequency changing works. Let's install another
454tool which is very handy for debugging purposes: <c>sys-power/cpufrequtils</c> 485tool which is very handy for debugging purposes: <c>sys-power/cpufrequtils</c>
480 511
481<p> 512<p>
482Now play around with <c>cpufreq-set</c> to make sure frequency switching works. 513Now play around with <c>cpufreq-set</c> to make sure frequency switching works.
483Run <c>cpufreq-set -g ondemand</c> for example to activate the ondemand 514Run <c>cpufreq-set -g ondemand</c> for example to activate the ondemand
484governor and verify the change with <c>cpufreq-info</c>. If it doesn't work as 515governor and verify the change with <c>cpufreq-info</c>. If it doesn't work as
485expected, you might find help in the Troubleshooting section in the end of this 516expected, you might find help in the <uri link="#doc_chap8">Troubleshooting
486guide. 517section</uri> in the end of this guide.
487</p> 518</p>
488 519
489</body> 520</body>
490</section> 521</section>
491<section> 522<section>
494 525
495<p> 526<p>
496The above is quite nice, but not doable in daily life. Better let your system 527The above is quite nice, but not doable in daily life. Better let your system
497set the appropriate frequency automatically. There are many different 528set the appropriate frequency automatically. There are many different
498approaches to do this. The following table gives a quick overview to help you 529approaches to do this. The following table gives a quick overview to help you
499decide on one of them. It's roughly seperated in three categories 530decide on one of them. It's roughly separated in three categories <b>kernel</b>
500<e>kernel</e> for approaches that only need kernel support, <e>daemon</e> for 531for approaches that only need kernel support, <b>daemon</b> for programs that
501programs that run in the background and <e>graphical</e> for programs that 532run in the background and <b>graphical</b> for programs that provide a GUI for
502provide a GUI for easy configuration and changes. 533easy configuration and changes.
503</p> 534</p>
504 535
505<table> 536<table>
506<tr> 537<tr>
507 <th>Name</th> 538 <th>Name</th>
530 <ti>Kernel</ti> 561 <ti>Kernel</ti>
531 <ti>CPU load</ti> 562 <ti>CPU load</ti>
532 <ti>N.A.</ti> 563 <ti>N.A.</ti>
533 <ti>N.A.</ti> 564 <ti>N.A.</ti>
534 <ti> 565 <ti>
535 Unlike the ondemand governor, conversative doesn't jump to maximum 566 Unlike the ondemand governor, conversative doesn't jump to maximum
536 frequency when CPU load is high, but increases the frequency step by 567 frequency when CPU load is high, but increases the frequency step by step.
537 step. Further tuning through files in 568 Further tuning through files in
538 <path>/sys/devices/system/cpu/cpu0/cpufreq/ondemand/</path>. Still 569 <path>/sys/devices/system/cpu/cpu0/cpufreq/ondemand/</path>. Still requires
539 requires userland tools (programs, scripts) if governor switching or 570 userland tools (programs, scripts) if governor switching or similar is
540 similar is desired. 571 desired.
541 </ti> 572 </ti>
542</tr> 573</tr>
543<tr> 574<tr>
544 <ti><uri link="http://mnm.uib.es/~gallir/cpudyn/">cpudyn</uri></ti> 575 <ti><uri link="http://mnm.uib.es/~gallir/cpudyn/">cpudyn</uri></ti>
545 <ti>Daemon</ti> 576 <ti>Daemon</ti>
552 </ti> 583 </ti>
553</tr> 584</tr>
554<tr> 585<tr>
555 <ti><uri link="http://sourceforge.net/projects/cpufreqd/">cpufreqd</uri></ti> 586 <ti><uri link="http://sourceforge.net/projects/cpufreqd/">cpufreqd</uri></ti>
556 <ti>Daemon</ti> 587 <ti>Daemon</ti>
557 <ti>Battery state, CPU load, temperature, running programs</ti> 588 <ti>Battery state, CPU load, temperature, running programs and more</ti>
558 <ti>All available</ti> 589 <ti>All available</ti>
559 <ti>None</ti> 590 <ti>None</ti>
560 <ti> 591 <ti>
561 Sophisticated (but also complicated) setup. 592 Sophisticated (but somewhat complicated) setup. Extendible through plugins
593 like sensor monitoring (lm_sensors) or coordinating some NVidia based
594 graphics card memory and core. Cpufreqd is SMP aware and can optionally be
595 controlled manually at runtime.
562 </ti> 596 </ti>
563</tr> 597</tr>
564<tr> 598<tr>
565 <ti> 599 <ti>
566 <uri link="http://www.deater.net/john/powernowd.html">powernowd</uri> 600 <uri link="http://www.deater.net/john/powernowd.html">powernowd</uri>
572 <ti> 606 <ti>
573 Supports SMP. 607 Supports SMP.
574 </ti> 608 </ti>
575</tr> 609</tr>
576<tr> 610<tr>
577 <ti> 611 <ti>ncpufreqd</ti>
578 <uri link="http://fatcat.ftj.agh.edu.pl/~nelchael/index.php?cat=projs&amp;subcat=ncpufreqd&amp;language=en">ncpufreqd</uri>
579 </ti>
580 <ti>Daemon</ti> 612 <ti>Daemon</ti>
581 <ti>Temperature</ti> 613 <ti>Temperature</ti>
582 <ti>None</ti> 614 <ti>None</ti>
583 <ti>Powersave, performance</ti> 615 <ti>Powersave, performance</ti>
584 <ti> 616 <ti>
623 655
624<p> 656<p>
625While adjusting the frequency to the current load looks simple at a first 657While adjusting the frequency to the current load looks simple at a first
626glance, it's not such a trivial task. A bad algorithm can cause switching 658glance, it's not such a trivial task. A bad algorithm can cause switching
627between two frequencies all the time or wasting energy when setting frequency 659between two frequencies all the time or wasting energy when setting frequency
628to an unnecessary high level. 660to an unnecessary high level.
629</p> 661</p>
630 662
631<p> 663<p>
632Which one to choose? If you have no idea about it, try <c>cpufreqd</c>: 664Which one to choose? If you have no idea about it, try <c>cpufreqd</c>:
633</p> 665</p>
637</pre> 669</pre>
638 670
639<p> 671<p>
640<c>cpufreqd</c> can be configured by editing <path>/etc/cpufreqd.conf</path>. 672<c>cpufreqd</c> can be configured by editing <path>/etc/cpufreqd.conf</path>.
641The default one that ships with cpufreqd may look a bit confusing. I recommend 673The default one that ships with cpufreqd may look a bit confusing. I recommend
642replacing it with the one from Gentoo developer Henrik Brix Andersen (see 674replacing it with the one from former Gentoo developer Henrik Brix Andersen
643below). 675(see below). Please notice that you need cpufreqd-2.0.0 or later. Earlier
676versions have a different syntax for the config file.
644</p> 677</p>
645 678
646<pre caption="/etc/cpufreqd.conf"> 679<pre caption="/etc/cpufreqd.conf (cpufreqd-2.0.0 and later)">
647[General] 680[General]
648pidfile=/var/run/cpufreqd.pid 681pidfile=/var/run/cpufreqd.pid
649poll_interval=2 682poll_interval=3
650pm_type=acpi 683enable_plugins=acpi_ac, acpi_battery
684enable_remote=1
685remote_group=wheel
651verbosity=5 686verbosity=5
687[/General]
652 688
653[Profile] 689[Profile]
654name=ondemand 690name=ondemand
655minfreq=0% 691minfreq=0%
656maxfreq=100% 692maxfreq=100%
657policy=ondemand 693policy=ondemand
694[/Profile]
658 695
659[Profile] 696[Profile]
660name=conservative 697name=conservative
661minfreq=0% 698minfreq=0%
662maxfreq=100% 699maxfreq=100%
663policy=conservative 700policy=conservative
701[/Profile]
664 702
665[Profile] 703[Profile]
666name=powersave 704name=powersave
667minfreq=0% 705minfreq=0%
668maxfreq=100% 706maxfreq=100%
669policy=powersave 707policy=powersave
708[/Profile]
670 709
671[Profile] 710[Profile]
672name=performance 711name=performance
673minfreq=0% 712minfreq=0%
674maxfreq=100% 713maxfreq=100%
675policy=performance 714policy=performance
715[/Profile]
676 716
677[Rule] 717[Rule]
678name=battery 718name=battery
679ac=off 719ac=off
680profile=conservative 720profile=conservative
721[/Rule]
681 722
682[Rule] 723[Rule]
683name=battery_low 724name=battery_low
684ac=off 725ac=off
685battery_interval=0-10 726battery_interval=0-10
686profile=powersave 727profile=powersave
728[/Rule]
687 729
688[Rule] 730[Rule]
689name=ac 731name=ac
690ac=on 732ac=on
691profile=ondemand 733profile=ondemand
734[/Rule]
692</pre> 735</pre>
693 736
694<p> 737<p>
695Now you can start the cpufreqd daemon. Add it to the <e>default</e> and 738Now you can start the cpufreqd daemon. Add it to the <c>default</c> and
696<e>battery</e> runlevel as well. 739<c>battery</c> runlevel as well.
697</p> 740</p>
698 741
699<pre caption="Starting cpufreqd"> 742<pre caption="Starting cpufreqd">
700# <i>rc-update add cpufreqd default battery</i> 743# <i>rc-update add cpufreqd default battery</i>
701# <i>rc</i> 744# <i>rc</i>
702</pre> 745</pre>
746
747<p>
748Sometimes it can be desirable to select another policy than the daemon chooses,
749for example when battery power is low, but you know that AC will be available
750soon. In that case you can turn on cpufreqd's manual mode with <c>cpufreqd-set
751manual</c> and select one of your configured policies (as listed by
752<c>cpufreqd-get</c>). You can leave manual mode by executing <c>cpufreqd-set
753dynamic</c>.
754</p>
703 755
704<warn> 756<warn>
705Do not run more than one of the above programs at the same time. It may cause 757Do not run more than one of the above programs at the same time. It may cause
706confusion like switching between two frequencies all the time. 758confusion like switching between two frequencies all the time.
707</warn> 759</warn>
708 760
709</body> 761</body>
710</section> 762</section>
711
712<section> 763<section>
713<title>Verifying the result</title> 764<title>Verifying the result</title>
714
715<body> 765<body>
716 766
717<p> 767<p>
718The last thing to check is that your new policies do a good job. An easy way to 768The last thing to check is that your new policies do a good job. An easy way to
719do so is monitoring CPU speed while working with your laptop: 769do so is monitoring CPU speed while working with your laptop:
722<pre caption="Monitoring CPU speed"> 772<pre caption="Monitoring CPU speed">
723# <i>watch grep \"cpu MHz\" /proc/cpuinfo</i> 773# <i>watch grep \"cpu MHz\" /proc/cpuinfo</i>
724</pre> 774</pre>
725 775
726<p> 776<p>
727If <path>/proc/cpuinfo</path> doesn't get updated (see Troubleshooting), 777If <path>/proc/cpuinfo</path> doesn't get updated (see <uri
728monitor the CPU frequency with: 778link="#doc_chap8">Troubleshooting</uri>), monitor the CPU frequency with:
729</p> 779</p>
730 780
731<pre caption="Alternative CPU speed monitoring"> 781<pre caption="Alternative CPU speed monitoring">
732# <i>watch x86info -mhz</i> 782# <i>watch x86info -mhz</i>
733</pre> 783</pre>
734 784
735<p> 785<p>
736Depending on your setup, CPU speed should increase on heavy load, decrease on 786Depending on your setup, CPU speed should increase on heavy load, decrease on
737no activity or just stay at the same level. When using cpufreqd and verbosity 787no activity or just stay at the same level. When using <c>cpufreqd</c> and
738set to 5 or higher in <path>cpufreqd.conf</path> you'll get additional 788verbosity set to 5 or higher in <path>cpufreqd.conf</path> you'll get
739information about what's happening reported to syslog. 789additional information about what's happening reported to <c>syslog</c>.
740</p> 790</p>
741 791
742</body> 792</body>
743</section> 793</section>
744</chapter> 794</chapter>
745 795
746<chapter> 796<chapter>
747<title>LCD Power Management</title> 797<title>LCD Power Management</title>
748<section> 798<section>
749<title>Energy consumer no. 1</title>
750<body> 799<body>
751 800
752<p> 801<p>
753As you can see in <uri link="#doc_chap1_fig1">figure 1.1</uri>, the LCD display 802As you can see in <uri link="#doc_chap1_fig1">figure 1.1</uri>, the LCD
754consumes the biggest part of energy (might not be the case for non-mobile 803display consumes the biggest part of energy (might not be the case for
755CPU's). Thus it's quite important not only to shut the display off when not 804non-mobile CPU's). Thus it's quite important not only to shut the display off
756needed, but also to reduce it's backlight if possible. Most laptops offer the 805when not needed, but also to reduce it's backlight if possible. Most laptops
757possibility to control the backlight dimming. 806offer the possibility to control the backlight dimming.
758</p>
759
760<p> 807</p>
808
809</body>
810</section>
811<section>
812<title>Standby settings</title>
813<body>
814
815<p>
761First thing to check is the standby/suspend/off timings of the display. As this 816The first thing to check is the standby/suspend/off timings of the display. As
762depends heavily on your windowmanager, I'll let you figure it out yourself. 817this depends heavily on your windowmanager, I'll let you figure it out
763Just two common places: Blanking the terminal can be done with <c>setterm 818yourself. Just two common places: Blanking the terminal can be done with
764-blank &lt;number-of-minutesM&gt;</c>, <c>setterm -powersave on</c> and 819<c>setterm -blank &lt;number-of-minutesM&gt;</c>, <c>setterm -powersave on</c>
765<c>setterm -powerdown &lt;number-of-minutesM&gt;</c>. 820and <c>setterm -powerdown &lt;number-of-minutesM&gt;</c>. For X.org, modify
766For X.org, modify <path>/etc/X11/xorg.conf</path> similar to this: 821<path>/etc/X11/xorg.conf</path> similar to this:
767</p> 822</p>
768 823
769<pre caption="LCD suspend settings in X.org and XFree86"> 824<pre caption="LCD suspend settings in X.org and XFree86">
770Section "ServerLayout" 825Section "ServerLayout"
771 Identifier [...] 826 Identifier [...]
788 843
789<p> 844<p>
790This is the same for XFree86 and <path>/etc/X11/XF86Config</path>. 845This is the same for XFree86 and <path>/etc/X11/XF86Config</path>.
791</p> 846</p>
792 847
848</body>
849</section>
850<section>
851<title>Backlight dimming</title>
852<body>
853
793<p> 854<p>
794Probably more important is the backlight dimming. If you have access to the 855Probably more important is the backlight dimming. If you have access to the
795dimming settings via a tool, write a small script that dims the backlight in 856dimming settings via a tool, write a small script that dims the backlight in
796battery mode and place it in your <e>battery</e> runlevel. The following script 857battery mode and place it in your <c>battery</c> runlevel. The following script
797should work on most IBM Thinkpads. It needs the <c>app-laptop/ibm-acpi</c> 858should work on most IBM Thinkpads and Toshiba laptops. You've got to enable the
798package or the appropriate option in your kernel has to be enabled. 859appropriate option in your kernel (IBM Thinkpads only). For Toshiba laptops,
860install <c>sys-power/acpitool</c> and skip configuration of <c>ibm_acpi</c> as
861described below.
799</p> 862</p>
800 863
801<warn> 864<warn>
802Support for setting brightness is marked experimental in ibm-acpi. It accesses 865Support for setting brightness is marked experimental in ibm-acpi. It accesses
803hardware directly and may cause severe harm to your system. Please read the 866hardware directly and may cause severe harm to your system. Please read the
809with the experimental parameter. 872with the experimental parameter.
810</p> 873</p>
811 874
812<pre caption="automatically loading the ibm_acpi module"> 875<pre caption="automatically loading the ibm_acpi module">
813<comment>(Please read the warnings above before doing this!)</comment> 876<comment>(Please read the warnings above before doing this!)</comment>
814<i># emerge ibm-acpi</i>
815<i># echo "options ibm_acpi experimental=1" >> /etc/modules.d/ibm_acpi</i> 877# <i>echo "options ibm_acpi experimental=1" >> /etc/modules.d/ibm_acpi</i>
816<i># /sbin/modules-update</i> 878# <i>/sbin/update-modules</i>
817<i># echo ibm_acpi >> /etc/modules.autoload.d/kernel-2.6</i> 879# <i>echo ibm_acpi >> /etc/modules.autoload.d/kernel-2.6</i>
818<i># modprobe ibm_acpi</i> 880# <i>modprobe ibm_acpi</i>
819</pre> 881</pre>
820 882
821<p> 883<p>
822This should work without error messages and a file 884This should work without error messages and a file
823<path>/proc/acpi/ibm/brightness</path> should be created after loading the 885<path>/proc/acpi/ibm/brightness</path> should be created after loading the
824module. An init script will take care of choosing the brightness according 886module. An init script will take care of choosing the brightness according to
825to the power source. 887the power source.
826</p> 888</p>
827 889
828<pre caption="/etc/conf.d/lcd-brightness"> 890<pre caption="/etc/conf.d/lcd-brightness">
829<comment># See /proc/acpi/ibm/brightness for available values</comment> 891<comment># See /proc/acpi/ibm/brightness for available values</comment>
830<comment># Please read /usr/share/doc/ibm-acpi-*/README.gz</comment> 892<comment># Please read /usr/src/linux/Documentation/ibm-acpi.txt</comment>
831 893
832<comment># brigthness level in ac mode. Default is 7.</comment> 894<comment># brightness level in ac mode. Default is 7.</comment>
833BRIGHTNESS_AC=7 895BRIGHTNESS_AC=7
834 896
835<comment># brightness level in battery mode. Default is 4.</comment> 897<comment># brightness level in battery mode. Default is 4.</comment>
836BRIGHTNESS_BATTERY=4 898BRIGHTNESS_BATTERY=4
837</pre> 899</pre>
850 if [ -f /proc/acpi/ibm/brightness ] 912 if [ -f /proc/acpi/ibm/brightness ]
851 then 913 then
852 ebegin "Setting LCD brightness" 914 ebegin "Setting LCD brightness"
853 echo "level ${LEVEL}" > /proc/acpi/ibm/brightness 915 echo "level ${LEVEL}" > /proc/acpi/ibm/brightness
854 eend $? 916 eend $?
917 elif [[ -e /usr/bin/acpitool &amp;&amp; -n $(acpitool -T | grep "LCD brightness") ]]
918 then
919 ebegin "Setting LCD brightness"
920 acpitool -l $LEVEL >/dev/null || ewarn "Unable to set lcd brightness"
921 eend $?
855 else 922 else
856 ewarn "Setting LCD brightness is not supported." 923 ewarn "Setting LCD brightness is not supported."
857 ewarn "Check that ibm_acpi is loaded into the kernel" 924 ewarn "For IBM Thinkpads, check that ibm_acpi is loaded into the kernel"
925 ewarn "For Toshiba laptops, you've got to install sys-power/acpitool"
858 fi 926 fi
859} 927}
860 928
861start() { 929start() {
862 set_brightness 930 set_brightness
871When done, make sure brightness is adjusted automatically by adding it to the 939When done, make sure brightness is adjusted automatically by adding it to the
872battery runlevel. 940battery runlevel.
873</p> 941</p>
874 942
875<pre caption="Enabling automatic brightness adjustment"> 943<pre caption="Enabling automatic brightness adjustment">
876<i># chmod +x /etc/init.d/lcd-brightness</i> 944# <i>chmod +x /etc/init.d/lcd-brightness</i>
877<i># rc-update add lcd-brightness battery</i> 945# <i>rc-update add lcd-brightness battery</i>
878<i># rc</i> 946# <i>rc</i>
879</pre> 947</pre>
880 948
881</body> 949</body>
882</section> 950</section>
883</chapter> 951</chapter>
884 952
885<chapter> 953<chapter>
886<title>Disk Power Management</title> 954<title>Disk Power Management</title>
887<section> 955<section>
888<title>Sleep when idle</title> 956<body>
957
958<p>
959Hard disks consume less energy in sleep mode. Therefore it makes sense to
960activate power saving features whenever the hard disk is not used for a certain
961amount of time. I'll show you two alternative possibilities to do it. First,
962laptop-mode will save most energy due to several measures which prevent or at
963least delay write accesses. The drawback is that due to the delayed write
964accesses a power outage or kernel crash will be more dangerous for data loss.
965If you don't like this, you have to make sure that there are no processes which
966write to your hard disk frequently. Afterwards you can enable power saving
967features of your hard disk with <c>hdparm</c> as the second alternative.
968</p>
969
889<body> 970</body>
971</section>
972<section>
973<title>Increasing idle time - laptop-mode</title>
974<body>
890 975
891<p>
892Let's bring the hard disk to sleep as early as possible whenever it is not
893needed. I'll show you two possibilities to do it. First <c>cpudyn</c> supports
894Disk Power Management. Uncomment the lines in the "Disk Options" section in
895<path>/etc/conf.d/cpudyn</path>. To put your first disk to sleep after 60
896seconds of no activity, you would modify it like this:
897</p> 976<p>
898 977Recent 2.6 kernels include the so-called <c>laptop-mode</c>. When activated,
899<pre caption="Using cpudyn for disk standby"> 978dirty buffers are written to disk on read calls or after 10 minutes (instead of
900<comment>################################################ 97930 seconds). This minimizes the time the hard disk needs to be spun up.
901# DISK OPTIONS
902# (disabled by default)
903################################################
904
905#
906# Timeout to put the disk in standby mode if there was no
907# io during that period (in seconds)
908#
909</comment>
910TIMEOUT=60
911<comment>
912#
913# Specified disks to spindown (comma separated devices)
914#
915</comment>
916DISKS=/dev/hda
917</pre>
918
919<p> 980</p>
920The second possibility is using a small script and hdparm. Create 981
921<path>/etc/init.d/pm.hda</path> like this: 982<pre caption="Automated start of laptop-mode">
983# <i>emerge laptop-mode-tools</i>
984</pre>
985
922</p> 986<p>
987<c>laptop-mode-tools</c> has its configuration file in
988<path>/etc/laptop-mode/laptop-mode.conf</path>. Adjust it the way you like it,
989it's well commented. Run <c>rc-update add laptop_mode battery</c> to start it
990automatically.
991</p>
923 992
993<p>
994Recent versions (1.11 and later) of laptop-mode-tools include a new tool
995<c>lm-profiler</c>. It will monitor your system's disk usage and running
996network services and suggests to disable unneeded ones. You can either disable
997them through laptop-mode-tools builtin runlevel support (which will be reverted
998by Gentoo's <c>/sbin/rc</c>) or use your <c>default</c>/<c>battery</c>
999runlevels (recommended).
1000</p>
1001
1002<pre caption="Sample output from running lm-profiler">
1003# <i>lm-profiler</i>
1004Profiling session started.
1005Time remaining: 600 seconds
1006[4296896.602000] amarokapp
1007Time remaining: 599 seconds
1008[4296897.714000] sort
1009[4296897.970000] mv
1010Time remaining: 598 seconds
1011Time remaining: 597 seconds
1012[4296900.482000] reiserfs/0
1013</pre>
1014
1015<p>
1016After profiling your system for ten minutes, lm-profiler will present a list of
1017services which might have caused disk accesses during that time.
1018</p>
1019
1020<pre caption="lm-profiler suggests to disable some services">
1021Program: "atd"
1022Reason: standard recommendation (program may not be running)
1023Init script: /etc/init.d/atd (GUESSED)
1024
1025Do you want to disable this service in battery mode? [y/N]: <i>n</i>
1026</pre>
1027
1028<p>
1029To disable atd as suggested in the example above, you would run <c>rc-update
1030del atd battery</c>. Be careful not to disable services that are needed for
1031your system to run properly - <c>lm-profiler</c> is likely to generate some
1032false positives. Do not disable a service if you are unsure whether it's
1033needed.
1034</p>
1035
1036</body>
1037</section>
1038<section>
1039<title>Limiting Write Accesses</title>
1040<body>
1041
1042<p>
1043If you don't want to use laptop-mode, you must take special care to disable
1044services that write to your disk frequently - <c>syslogd</c> is a good
1045candidate, for example. You probably don't want to shut it down completely, but
1046it's possible to modify the config file so that "unnecessary" things don't get
1047logged and thus don't create disk traffic. <c>Cups</c> writes to disk
1048periodically, so consider shutting it down and only enable it manually when
1049needed.
1050</p>
1051
1052<pre caption="Disabling cups in battery mode">
1053# <i>rc-update del cupsd battery</i>
1054</pre>
1055
1056<p>
1057You can also use <c>lm-profiler</c> from laptop-mode-tools (see above) to find
1058services to disable. Once you eliminated all of them, go on with configuring
1059hdparm.
1060</p>
1061
1062</body>
1063</section>
1064<section>
1065<title>hdparm</title>
1066<body>
1067
1068<p>
1069The second possibility is using <c>hdparm</c>. Skip this if
1070you are using laptop-mode. Otherwise, edit <path>/etc/conf.d/hdparm</path> and
1071add the following values to your drive entries. This example assumes your hard
1072drive is called <b>hda</b>:
1073</p>
1074
924<pre caption="Using hdparm for disk standby"> 1075<pre caption="Using /etc/conf.d/hdparm for disk standby">
925#!/sbin/runscript 1076hda_args="-q -S12"
926
927depend() {
928 after hdparm
929}
930
931start() {
932 ebegin "Activating Power Management for Hard Drives"
933 hdparm -q -S12 /dev/hda
934 eend $?
935}
936
937stop () {
938 ebegin "Deactivating Power Management for Hard Drives"
939 hdparm -q -S253 /dev/hda
940 eend $?
941}
942</pre> 1077</pre>
943 1078
1079<p>
1080This will activate power management for your hard drive. If you ever want to
1081deactivate power management, you can edit <path>/etc/conf.d/hdparm</path> and
1082change the values to <c>-q -S0</c>, or just run <c>hdparm -q -S0 /dev/hda</c>.
944<p> 1083</p>
945See <c>man hdparm</c> for the options. If your script is ready, add it to the 1084
946battery runlevel. 1085<p>
1086See <c>man hdparm</c> for the options. Though you can always start <c>hdparm</c>
1087manually when you are on battery power by running <c>/etc/init.d/hdparm
1088start</c>, it's much easier to automate its startup and shutdown. To do so, add
1089<c>hdparm</c> to the battery runlevel so that it will automatically enable power
1090management.
947</p> 1091</p>
948 1092
949<pre caption="Automate disk standby settings"> 1093<pre caption="Automate disk standby settings">
950# <i>chmod +x /etc/init.d/pm.hda</i>
951# <i>/sbin/depscan.sh</i>
952# <i>rc-update add pm.hda battery</i> 1094# <i>rc-update add hdparm battery</i>
953</pre> 1095</pre>
954 1096
955<impo> 1097<impo>
956Be careful with sleep/spin down settings of your hard drive. Setting it to 1098Be careful with sleep/spin down settings of your hard drive. Setting it to
957small values might wear out your drive and lose warranty. 1099small values might wear out your drive and lose warranty.
958</impo> 1100</impo>
959 1101
960</body> 1102</body>
961</section> 1103</section>
962<section> 1104<section>
963<title>Increasing idle time - laptop-mode</title>
964<body>
965
966<p>
967Recent kernels (2.6.6 and greater, recent 2.4 ones and others with patches)
968include the so-called <e>laptop-mode</e>. When activated, dirty buffers are
969written to disk on read calls or after 10 minutes (instead of 30 seconds). This
970minimizes the time the hard disk needs to be spun up.
971</p>
972
973<pre caption="Automated start of laptop-mode">
974# <i>emerge laptop-mode-tools</i>
975</pre>
976
977<p>
978<c>laptop-mode-tools</c> has it's configuration file in
979<path>/etc/laptop-mode/laptop-mode.conf</path>. Adjust it the way you like it,
980it's well commented. Run <c>rc-update add laptop_mode battery</c> to start it
981automatically.
982</p>
983
984</body>
985</section>
986<section>
987<title>Other tricks</title> 1105<title>Other tricks</title>
988<body> 1106<body>
989
990<p>
991Besides putting your disk to sleep state as early as possible, it is a good
992idea to minimize disk accesses. Have a look at processes that write to your
993disk frequently - the syslogd is a good candidate. You probably don't want to
994shut it down completely, but it's possible to modify the config file so that
995"unnecessary" things don't get logged and thus don't create disk traffic. Cups
996writes to disk periodically, so consider shutting it down and only enable it
997manually when needed.
998</p>
999
1000<pre caption="Disabling cups in battery mode">
1001# <i>rc-update del cupsd battery</i>
1002</pre>
1003 1107
1004<p> 1108<p>
1005Another possibility is to deactivate swap in battery mode. Before writing a 1109Another possibility is to deactivate swap in battery mode. Before writing a
1006swapon/swapoff switcher, make sure there is enough RAM and swap isn't used 1110swapon/swapoff switcher, make sure there is enough RAM and swap isn't used
1007heavily, otherwise you'll be in big problems. 1111heavily, otherwise you'll be in big problems.
1008</p> 1112</p>
1009 1113
1010<p> 1114<p>
1011If you don't want to use laptop-mode, it's still possible to minimize disk 1115If you don't want to use laptop-mode, it's still possible to minimize disk
1012access by mounting certain directories as <e>tmpfs</e> - write accesses are not 1116access by mounting certain directories as <c>tmpfs</c> - write accesses are not
1013stored on a disk, but in main memory and get lost with unmounting. Often it's 1117stored on a disk, but in main memory and get lost with unmounting. Often it's
1014useful to mount <path>/tmp</path> like this - you don't have to pay special 1118useful to mount <path>/tmp</path> like this - you don't have to pay special
1015attention as it gets cleared on every reboot regardless whether it was mounted 1119attention as it gets cleared on every reboot regardless whether it was mounted
1016on disk or in RAM. Just make sure you have enough RAM and no program (like a 1120on disk or in RAM. Just make sure you have enough RAM and no program (like a
1017download client or compress utility) needs extraordinary much space in 1121download client or compress utility) needs extraordinary much space in
1023none /tmp tmpfs size=32m 0 0 1127none /tmp tmpfs size=32m 0 0
1024</pre> 1128</pre>
1025 1129
1026<warn> 1130<warn>
1027Pay attention to the size parameter and modify it for your system. If you're 1131Pay attention to the size parameter and modify it for your system. If you're
1028unsure, don't try this at all, it can become a perfomance bottleneck easily. In 1132unsure, don't try this at all, it can become a performance bottleneck easily. In
1029case you want to mount <path>/var/log</path> like this, make sure to merge the 1133case you want to mount <path>/var/log</path> like this, make sure to merge the
1030log files to disk before unmounting. They are essential. Don't attempt to mount 1134log files to disk before unmounting. They are essential. Don't attempt to mount
1031/var/tmp like this. Portage uses it for compiling... 1135<path>/var/tmp</path> like this. Portage uses it for compiling...
1032</warn> 1136</warn>
1033 1137
1034</body> 1138</body>
1035</section> 1139</section>
1036</chapter> 1140</chapter>
1037 1141
1038<chapter> 1142<chapter>
1039<title>Power Management for other devices</title> 1143<title>Power Management For Other Devices</title>
1040<section> 1144<section>
1041<title>Graphics cards</title> 1145<title>Graphics Cards</title>
1042<body> 1146<body>
1043 1147
1044<p> 1148<p>
1045In case you own an ATI graphics card supporting PowerPlay (dynamic clock 1149In case you own an ATI graphics card supporting PowerPlay (dynamic clock
1046scaling for the the graphics processing unit GPU), you can activate this 1150scaling for the graphics processing unit GPU), you can activate this
1047feature in X.org. Open <path>/etc/X11/xorg.conf</path> and add (or enable) 1151feature in X.org. Open <path>/etc/X11/xorg.conf</path> and add (or enable) the
1048the <c>DynamicClocks</c> option in the Device section. Please notice that 1152<c>DynamicClocks</c> option in the Device section. Please notice that this
1049this feature will lead to crashes on some systems. 1153feature will lead to crashes on some systems.
1050</p> 1154</p>
1051 1155
1052<pre caption="Enabling ATI PowerPlay support in X.org"> 1156<pre caption="Enabling ATI PowerPlay support in X.org">
1053Section "Device" 1157Section "Device"
1054[...] 1158[...]
1061<section> 1165<section>
1062<title>Wireless Power Management</title> 1166<title>Wireless Power Management</title>
1063<body> 1167<body>
1064 1168
1065<p> 1169<p>
1066Wireless LAN cards consume quite a few energy. Put them in Power Management 1170Wireless LAN cards consume quite a bit of energy. Put them in Power Management
1067mode in analogy to the pm.hda script. 1171mode just like your hard drives.
1068</p>
1069
1070<pre caption="WLAN Power Management automated">
1071#!/sbin/runscript
1072start() {
1073 ebegin "Activating Power Management for Wireless LAN"
1074 iwconfig wlan0 power on power max period 3
1075 eend $?
1076}
1077
1078stop () {
1079 ebegin "Deactivating Power Management for Wireless LAN"
1080 iwconfig wlan0 power off
1081 eend $?
1082}
1083</pre>
1084
1085<p> 1172</p>
1086Starting this script will put wlan0 in Power Management mode, going to sleep at 1173
1087the latest three seconds after no traffic. 1174<note>
1088Save it as <path>/etc/init.d/pm.wlan0</path> and add it to the battery runlevel 1175This script assumes your wireless interface is called <c>wlan0</c>; replace
1089like the disk script above. See <c>man iwconfig</c> for details and more 1176this with the actual name of your interface.
1090options. If your driver and access point support changing the beacon time, this 1177</note>
1091is a good starting point to save even more energy. 1178
1092</p> 1179<p>
1093 1180Add the following option to <path>/etc/conf.d/net</path> to automatically enable
1094<pre caption="Power Management for WLAN"> 1181power management for your wireless card:
1095# <i>chmod +x /etc/init.d/pm.wlan0</i>
1096# <i>/sbin/depscan.sh</i>
1097# <i>rc-update add pm.wlan0 battery</i>
1098</pre> 1182</p>
1183
1184<pre caption="Automated WLAN Power Management">
1185iwconfig_wlan0="power on"
1186</pre>
1187
1188<p>
1189See <c>man iwconfig</c> for details and more options like the period between
1190wakeups or timeout settings. If your driver and access point support changing
1191the beacon time, this is a good starting point to save even more energy.
1192</p>
1099 1193
1100</body> 1194</body>
1101</section> 1195</section>
1102<section> 1196<section>
1103<title>USB Power Management</title> 1197<title>USB Power Management</title>
1107There are two problems with USB devices regarding energy consumption: First, 1201There are two problems with USB devices regarding energy consumption: First,
1108devices like USB mice, digital cameras or USB sticks consume energy while 1202devices like USB mice, digital cameras or USB sticks consume energy while
1109plugged in. You cannot avoid this (nevertheless remove them in case they're not 1203plugged in. You cannot avoid this (nevertheless remove them in case they're not
1110needed). Second, when there are USB devices plugged in, the USB host controller 1204needed). Second, when there are USB devices plugged in, the USB host controller
1111periodically accesses the bus which in turn prevents the CPU from going into 1205periodically accesses the bus which in turn prevents the CPU from going into
1112sleep mode. The kernel offers an experimental option to enable suspension of 1206sleep mode. The kernel offers an experimental option to enable suspension of
1113USB devices through driver calls or one of the <path>power/state</path> files 1207USB devices through driver calls or one of the <path>power/state</path> files
1114in <path>/sys</path>. 1208in <path>/sys</path>.
1115</p> 1209</p>
1116 1210
1117<pre caption="Enabling USB suspend support in the kernel"> 1211<pre caption="Enabling USB suspend support in the kernel">
1124</body> 1218</body>
1125</section> 1219</section>
1126</chapter> 1220</chapter>
1127 1221
1128<chapter> 1222<chapter>
1129<title>Sleep states: sleep, standby, suspend to disk</title> 1223<title>Sleep States: sleep, standby, and suspend to disk</title>
1130<section> 1224<section>
1131<title>Overview</title>
1132<body> 1225<body>
1133 1226
1134<p> 1227<p>
1135ACPI defines different sleep states. The more important ones are 1228ACPI defines different sleep states. The more important ones are
1136</p> 1229</p>
1137 1230
1138<ul> 1231<ul>
1139 <li>S1 aka Standby</li> 1232 <li>S1 aka Standby</li>
1140 <li>S3 aka Suspend to RAM aka Sleep</li> 1233 <li>S3 aka Suspend to RAM aka Sleep</li>
1141 <li>S4 aka Suspend to Disk aka Hibernate</li> 1234 <li>S4 aka Suspend to Disk aka Hibernate</li>
1142</ul> 1235</ul>
1143 1236
1165 [*] ACPI Support 1258 [*] ACPI Support
1166 [*] Sleep States 1259 [*] Sleep States
1167</pre> 1260</pre>
1168 1261
1169<p> 1262<p>
1170Once your kernel is prepared like above, you can use the 1263Once your kernel is properly configured, you can use the
1171<c>hibernate-script</c> to activate suspend or sleep mode. Let's install that 1264<c>hibernate-script</c> to activate suspend or sleep mode. Let's install that
1172first. 1265first.
1173</p> 1266</p>
1174 1267
1175<pre caption="Installing the hibernate-script"> 1268<pre caption="Installing the hibernate-script">
1176<i># emerge hibernate-script</i> 1269# <i>emerge hibernate-script</i>
1177</pre> 1270</pre>
1178 1271
1179<p> 1272<p>
1180Some configuration has to be done in <path>/etc/hibernate</path> The default 1273Some configuration has to be done in <path>/etc/hibernate</path>. The default
1181package introduces two configuration files <path>hibernate.conf</path> and 1274package introduces a few configuration files for each sleep state. Options that
1182<path>ram.conf</path>. 1275are common to all suspend methods are placed in <path>common.conf</path>; make
1183</p> 1276sure this file is properly set up for your system.
1184
1185<p> 1277</p>
1186To configure sleep, edit <path>ram.conf</path> in <path>/etc/hibernate</path>. 1278
1187<c>UseSysfsPowerState mem</c> is already setup correctly, but you have to go
1188through the rest of the configuration file and set it up for your system. The
1189comments and option names will guide you. If you use nfs or samba shares over
1190the network, make sure to shutdown the appropriate init scripts to avoid
1191timeouts.
1192</p> 1279<p>
1280To configure sleep, edit <path>sysfs-ram.conf</path> in
1281<path>/etc/hibernate</path>. <c>UseSysfsPowerState mem</c> is already setup
1282correctly, but if you need to make further changes to this particular sleep
1283state (or any other sleep state) you should add them to
1284<path>/etc/hibernate/hibernate.conf</path>. The comments and option names will
1285guide you. If you use nfs or samba shares over the network, make sure to
1286shutdown the appropriate init scripts to avoid timeouts.
1287</p>
1288
1289<note>
1290For more information on setting up sleep states, read <c>man
1291hibernate.conf</c>.
1292</note>
1193 1293
1194<p> 1294<p>
1195Ready? Now is the last chance to backup any data you want to keep after 1295Ready? Now is the last chance to backup any data you want to keep after
1196executing the next command. Notice that you probably have to hit a special key 1296executing the next command. Notice that you probably have to hit a special key
1197like <e>Fn</e> to resume from sleep. 1297like <c>Fn</c> to resume from sleep.
1198</p> 1298</p>
1199 1299
1200<pre caption="Calling sleep"> 1300<pre caption="Calling sleep">
1201<i># hibernate-ram</i> 1301# <i>hibernate-ram</i>
1202</pre> 1302</pre>
1203 1303
1204<p> 1304<p>
1205If you're still reading, it seems to work. You can also setup standby (S1) in 1305If you're still reading, it seems to work. You can also setup standby (S1) in a
1206a similar way by copying <path>ram.conf</path> to <path>standby.conf</path> 1306similar way by editing <path>sysfs-ram.conf</path> and changing
1207and creating a symlink <path>/usr/sbin/hibernate-standby</path> pointing to 1307"UseSysfsPowerState mem" to "UseSysfsPowerState standby". S3 and S4 are the more
1208<path>/usr/sbin/hibernate</path>. S3 and S4 are the more interesting sleep
1209states due to greater energy savings however. 1308interesting sleep states due to greater energy savings however.
1210</p> 1309</p>
1211 1310
1212</body> 1311</body>
1213</section> 1312</section>
1214<section> 1313<section>
1227Shutdown any NFS or samba server/client before hibernating. 1326Shutdown any NFS or samba server/client before hibernating.
1228</warn> 1327</warn>
1229 1328
1230<p> 1329<p>
1231There are two different implementations for S4. The original one is swsusp, 1330There are two different implementations for S4. The original one is swsusp,
1232then there is the newer suspend2 with a nicer interface (including 1331then there is the newer suspend2 with a nicer interface (including fbsplash
1233fbsplash support). A <uri link="http://suspend2.net/features.html#compare"> 1332support). A <uri link="http://suspend2.net/features.html#compare"> feature
1234feature comparison</uri> is available at the <uri link="http://suspend2.net"> 1333comparison</uri> is available at the <uri link="http://suspend2.net"> suspend2
1235suspend2 Homepage</uri>. There used to be Suspend-to-Disk (pmdisk), a fork of 1334Homepage</uri>. There used to be Suspend-to-Disk (pmdisk), a fork of swsusp,
1236swsusp, but it has been merged back. 1335but it has been merged back.
1237</p> 1336</p>
1238 1337
1239<p> 1338<p>
1240Suspend2 is not included in the mainline kernel yet, therefore you either have 1339Suspend2 is not included in the mainline kernel yet, therefore you either have
1241to patch your kernel sources with the patches provided by 1340to patch your kernel sources with the patches provided by <uri
1242<uri link="http://suspend2.net">suspend2.net</uri> or use 1341link="http://suspend2.net">suspend2.net</uri> or use
1243<c>sys-kernel/suspend2-sources</c>. 1342<c>sys-kernel/suspend2-sources</c>.
1244</p> 1343</p>
1245 1344
1246<p> 1345<p>
1247The kernel part for both swusp and suspend2 is as follows: 1346The kernel part for both swusp and suspend2 is as follows:
1251Power Management Options ---&gt; 1350Power Management Options ---&gt;
1252 <comment>(hibernate with swsusp)</comment> 1351 <comment>(hibernate with swsusp)</comment>
1253 [*] Software Suspend 1352 [*] Software Suspend
1254 <comment>(replace /dev/SWAP with your swap partition)</comment> 1353 <comment>(replace /dev/SWAP with your swap partition)</comment>
1255 (/dev/SWAP) Default resume partition 1354 (/dev/SWAP) Default resume partition
1256 1355
1257 <comment>(hibernate with suspend2)</comment> 1356 <comment>(hibernate with suspend2)</comment>
1258 Software Suspend 2 1357 Software Suspend 2
1259 --- Image Storage (you need at least one writer) 1358 --- Image Storage (you need at least one writer)
1260 [*] File Writer 1359 [*] File Writer
1261 [*] Swap Writer 1360 [*] Swap Writer
1269<p> 1368<p>
1270The configuration for swsusp is rather easy. If you didn't store the location 1369The configuration for swsusp is rather easy. If you didn't store the location
1271of your swap partition in the kernel config, you can also pass it as a 1370of your swap partition in the kernel config, you can also pass it as a
1272parameter with the <c>resume=/dev/SWAP</c> directive. If booting is not 1371parameter with the <c>resume=/dev/SWAP</c> directive. If booting is not
1273possible due to a broken image, use the <c>noresume</c> kernel parameter. The 1372possible due to a broken image, use the <c>noresume</c> kernel parameter. The
1274<c>hibernate-cleanup</c> init script invalidates swsusp images during the 1373<c>hibernate-cleanup</c> init script invalidates swsusp images during the boot
1275boot process. 1374process.
1276</p> 1375</p>
1277 1376
1278<pre caption="Invalidating swsusp images during the boot process"> 1377<pre caption="Invalidating swsusp images during the boot process">
1279<i># rc-update add hibernate-cleanup boot</i> 1378# <i>rc-update add hibernate-cleanup boot</i>
1280</pre> 1379</pre>
1281 1380
1282<p> 1381<p>
1283To activate hibernate with swsusp, use the hibernate script and set 1382To activate hibernate with swsusp, use the hibernate script and set
1284<c>UseSysfsPowerState disk</c> in <path>/etc/hibernate/hibernate.conf</path>. 1383<c>UseSysfsPowerState disk</c> in <path>/etc/hibernate/sysfs-disk</path>.
1285</p> 1384</p>
1286 1385
1287<warn> 1386<warn>
1288Backup your data before doing this. Run <c>sync</c> before executing one of the 1387Backup your data before doing this. Run <c>sync</c> before executing one of the
1289commands to have cached data written to disk. First try it outside of X, then 1388commands to have cached data written to disk. First try it outside of X, then
1290with X running, but not logged in. 1389with X running, but not logged in.
1291</warn> 1390</warn>
1292 1391
1293<p> 1392<p>
1294If you experience kernel panics due to uhci or similar, try to compile USB 1393If you experience kernel panics due to uhci or similar, try to compile USB
1295support as module and unload the modules before sending your laptop to sleep 1394support as module and unload the modules before sending your laptop to sleep
1296mode. There are configuration options for this in <path>hibernate.conf</path> 1395mode. There are configuration options for this in <path>common.conf</path>
1297</p> 1396</p>
1298 1397
1299<pre caption="Hibernating with swsusp"> 1398<pre caption="Hibernating with swsusp">
1300<i># nano -w /etc/hibernate.conf</i> 1399# <i>nano -w /etc/hibernate/common.conf</i>
1301<comment>(Make sure you have a backup of your data)</comment> 1400<comment>(Make sure you have a backup of your data)</comment>
1302<i># hibernate</i> 1401# <i>hibernate</i>
1303</pre> 1402</pre>
1304 1403
1305<p> 1404<p>
1306The following section discusses the setup of suspend2 including fbsplash 1405The following section discusses the setup of suspend2 including fbsplash
1307support for a nice graphical progress bar during suspend and resume. 1406support for a nice graphical progress bar during suspend and resume.
1308</p> 1407</p>
1309 1408
1310<p> 1409<p>
1311The first part of the configuration is similar to the configuration of 1410The first part of the configuration is similar to the configuration of swsusp.
1312swsusp. In case you didn't store the location of your swap partition in the 1411In case you didn't store the location of your swap partition in the kernel
1313kernel config, you have to pass it as a kernel parameter with the 1412config, you have to pass it as a kernel parameter with the
1314<c>resume2=swap:/dev/SWAP</c> directive. If booting is not possible due to a 1413<c>resume2=swap:/dev/SWAP</c> directive. If booting is not possible due to a
1315broken image, append the <c>noresume2</c> parameter. Additionally, the 1414broken image, append the <c>noresume2</c> parameter. Additionally, the
1316<c>hibernate-cleanup</c> init script invalidates suspend2 images during the 1415<c>hibernate-cleanup</c> init script invalidates suspend2 images during the
1317boot process. 1416boot process.
1318</p> 1417</p>
1319 1418
1320<pre caption="Invalidating suspend2 images during the boot process"> 1419<pre caption="Invalidating suspend2 images during the boot process">
1321<i># rc-update add hibernate-cleanup boot</i> 1420# <i>rc-update add hibernate-cleanup boot</i>
1322</pre> 1421</pre>
1323 1422
1423<p>
1324<p>Now edit <path>/etc/hibernate/hibernate.conf</path>, enable the 1424Now edit <path>/etc/hibernate/suspend2.conf</path>, enable the <c>suspend2</c>
1325<e>suspend2</e> section and comment everything in the <e>sysfs_power_state</e> 1425options you need. Do not enable the <c>fbsplash</c> options in
1326and <e>acpi_sleep</e> sections. Do not enable the fbsplash part in global 1426<c>common.conf</c> just yet.
1327options yet.
1328</p> 1427</p>
1329 1428
1330<pre caption="Hibernating with suspend2"> 1429<pre caption="Hibernating with suspend2">
1331<i># nano -w /etc/hibernate.conf</i> 1430# <i>nano -w /etc/hibernate/suspend2.conf</i>
1332<comment>(Make sure you have a backup of your data)</comment> 1431<comment>(Make sure you have a backup of your data)</comment>
1333<i># hibernate</i> 1432# <i>hibernate</i>
1334</pre> 1433</pre>
1335 1434
1336<p> 1435<p>
1337Please configure fbsplash now if you didn't do already. To enable fbsplash 1436Please configure <c>fbsplash</c> now if you didn't do already. To enable
1338support during hibernation, the <c>sys-apps/suspend2-userui</c> package is 1437fbsplash support during hibernation, the <c>sys-apps/suspend2-userui</c>
1339needed. Additionally, you've got to enable the <e>fbsplash</e> USE flag. 1438package is needed. Additionally, you've got to enable the <c>fbsplash</c> USE
1439flag.
1340</p> 1440</p>
1341 1441
1342<pre caption="Installing suspend2-userui"> 1442<pre caption="Installing suspend2-userui">
1343<i># mkdir -p /etc/portage</i>
1344<i># echo sys-apps/suspend2-userui fbsplash >> /etc/portage/package.use</i> 1443# <i>echo "sys-apps/suspend2-userui fbsplash" >> /etc/portage/package.use</i>
1444<comment>(It may be marked ~arch, so first it must be keyworded)</comment>
1445# <i>echo "sys-apps/suspend2-userui" >> /etc/portage/package.keywords</i>
1345<i># emerge suspend2-userui</i> 1446# <i>emerge suspend2-userui</i>
1346</pre> 1447</pre>
1347 1448
1348<p> 1449<p>
1349The ebuild tells you to make a symlink to the theme you want to use. For 1450The ebuild tells you to make a symlink to the theme you want to use. For
1350example, to use the <c>livecd-2005.1</c> theme, run the following command: 1451example, to use the <c>livecd-2005.1</c> theme, run the following command:
1351</p> 1452</p>
1352 1453
1353<pre caption="Using the livecd-2005.1 theme during hibernation"> 1454<pre caption="Using the livecd-2005.1 theme during hibernation">
1354<i># ln -sfn /etc/splash/livecd-2005.1 /etc/splash/suspend2</i> 1455# <i>ln -sfn /etc/splash/livecd-2005.1 /etc/splash/suspend2</i>
1355</pre> 1456</pre>
1356 1457
1357<p> 1458<p>
1358If you don't want a black screen in the first part of the resume process, you 1459If you don't want a black screen in the first part of the resume process, you
1359have to add the <c>suspend2ui_fbsplash</c> tool to your initrd image. Assuming 1460have to add the <c>suspend2ui_fbsplash</c> tool to your initrd image. Assuming
1360you created the initrd image with <c>splash_geninitramfs</c> and saved it as 1461you created the initrd image with <c>splash_geninitramfs</c> and saved it as
1361<path>/boot/fbsplash-emergence-1024x768</path>, here's how to do 1462<path>/boot/fbsplash-emergence-1024x768</path>, here's how to do that.
1362that.
1363</p> 1463</p>
1364 1464
1365<pre caption="Adding suspend2ui_fbsplash to an initrd image"> 1465<pre caption="Adding suspend2ui_fbsplash to an initrd image">
1366<i># mount /boot</i> 1466# <i>mount /boot</i>
1367<i># mkdir ~/initrd.d</i> 1467# <i>mkdir ~/initrd.d</i>
1368<i># cp /boot/fbsplash-emergence-1024x768 ~/initrd.d/</i> 1468# <i>cp /boot/fbsplash-emergence-1024x768 ~/initrd.d/</i>
1369<i># cd ~/initrd.d</i> 1469# <i>cd ~/initrd.d</i>
1370<i># gunzip -c fbsplash-emergence-1024x768 | cpio -idm --quiet -H newc</i> 1470# <i>gunzip -c fbsplash-emergence-1024x768 | cpio -idm --quiet -H newc</i>
1371<i># rm fbsplash-emergence-1024x768</i> 1471# <i>rm fbsplash-emergence-1024x768</i>
1372<i># cp /usr/sbin/suspend2ui_fbsplash sbin/</i> 1472# <i>cp /usr/sbin/suspend2ui_fbsplash sbin/</i>
1373<i># find . | cpio --quiet --dereference -o -H newc | gzip -9 > /boot/fbsplash-suspend2-emergence-1024x768</i> 1473# <i>find . | cpio --quiet --dereference -o -H newc | gzip -9 > /boot/fbsplash-suspend2-emergence-1024x768</i>
1374</pre> 1474</pre>
1375 1475
1376<p> 1476<p>
1377Afterwards adjust <path>grub.conf</path> respectively <path>lilo.conf</path> 1477Afterwards adjust <path>grub.conf</path> (or <path>lilo.conf</path>) so that
1378so that your suspend2 kernel uses 1478your suspend2 kernel uses
1379<path>/boot/fbsplash-suspend2-emergence-1024x768</path> as initrd image. You 1479<path>/boot/fbsplash-suspend2-emergence-1024x768</path> as initrd image. You can
1380can now test a dry run to see if everything is setup correctly. 1480now test a dry run to see if everything is setup correctly.
1381</p> 1481</p>
1382 1482
1383<pre caption="Test run for fbsplash hibernation"> 1483<pre caption="Test run for fbsplash hibernation">
1384<i># suspend2ui_fbsplash -t</i> 1484# <i>suspend2ui_fbsplash -t</i>
1385</pre> 1485</pre>
1386 1486
1387<p> 1487<p>
1388Afterwards open <path>/etc/hibernate/hibernate.conf</path> again and activate 1488Afterwards open <path>/etc/hibernate/common.conf</path> and activate the
1389the fbsplash options. Execute <c>hibernate</c> and enjoy. 1489fbsplash options. Execute <c>hibernate</c> and enjoy.
1390</p> 1490</p>
1391 1491
1392</body> 1492</body>
1393</section> 1493</section>
1394</chapter> 1494</chapter>
1395 1495
1396<chapter> 1496<chapter>
1397<title>Troubleshooting</title> 1497<title>Troubleshooting</title>
1398<section> 1498<section>
1399<title>If things go wrong...</title>
1400<body> 1499<body>
1401 1500
1402<p> 1501<p>
1403<e>Q:</e> I'm trying to change the CPU frequency, but 1502<e>Q:</e> I'm trying to change the CPU frequency, but
1404<path>/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor</path> does not 1503<path>/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor</path> does not
1429Try to update the BIOS, especially if a broken DSDT is reported. You can also 1528Try to update the BIOS, especially if a broken DSDT is reported. You can also
1430try to fix it yourself (which is beyond the scope of this guide). 1529try to fix it yourself (which is beyond the scope of this guide).
1431</p> 1530</p>
1432 1531
1433<p> 1532<p>
1434<e>Q:</e> My laptop supports frequency scaling, but according to /proc/cpuinfo 1533<e>Q:</e> My laptop supports frequency scaling, but according to
1435the speed never changes. 1534<path>/proc/cpuinfo</path> the speed never changes.
1436</p> 1535</p>
1437 1536
1438<p> 1537<p>
1439<e>A:</e> Probably you have activated symmetric multiprocessing support 1538<e>A:</e> Probably you have activated symmetric multiprocessing support
1440(CONFIG_SMP) in your kernel. Deactivate it and it should work. Some older 1539(CONFIG_SMP) in your kernel. Deactivate it and it should work. Some older
1441kernels had a bug causing this. In that case, run <c>emerge x86info</c>, 1540kernels had a bug causing this. In that case, run <c>emerge x86info</c>, update
1442update your kernel as asked and check the current frequency with 1541your kernel as asked and check the current frequency with
1443<c>x86info -mhz</c>. 1542<c>x86info -mhz</c>.
1444</p> 1543</p>
1445 1544
1446<p> 1545<p>
1447<e>Q:</e> I can change the CPU frequency, but the range is not as wide as in 1546<e>Q:</e> I can change the CPU frequency, but the range is not as wide as in
1486<e>A:</e> Check that battery support is compiled into your kernel. If you use 1585<e>A:</e> Check that battery support is compiled into your kernel. If you use
1487it as a module, make sure the module is loaded. 1586it as a module, make sure the module is loaded.
1488</p> 1587</p>
1489 1588
1490<p> 1589<p>
1590<e>Q:</e> My system logger reports things like "logger: ACPI group battery /
1591action battery is not defined".
1592</p>
1593
1594<p>
1595<e>A:</e> This message is generated by the <path>/etc/acpi/default.sh</path>
1596script that is shipped with acpid. You can safely ignore it. If you like to get
1597rid of it, you can comment the appropriate line in
1598<path>/etc/acpi/default.sh</path> as shown below:
1599</p>
1600
1601<pre caption="Disabling warnings about unknown acpi events">
1602 *) # logger "ACPI action $action is not defined"
1603</pre>
1604
1605<p>
1491<e>Q:</e> I have a Dell Inspiron 51XX and I don't get any ACPI events. 1606<e>Q:</e> I have a Dell Inspiron 51XX and I don't get any ACPI events.
1492</p> 1607</p>
1493 1608
1494<p> 1609<p>
1495<e>A:</e> This seems to be a kernel bug. Read on <uri 1610<e>A:</e> This seems to be a kernel bug. Read on <uri
1496link="http://bugme.osdl.org/show_bug.cgi?id=1752">here</uri>. 1611link="http://bugme.osdl.org/show_bug.cgi?id=1752">here</uri>.
1497</p> 1612</p>
1498 1613
1499<p> 1614<p>
1500<e>Q:</e> I activated the DynamicClocks option in <path>xorg.conf</path> and 1615<e>Q:</e> I activated the <c>DynamicClocks</c> option in <path>xorg.conf</path>
1501now X.org crashes / the screen stays black / my laptop doesn't shutdown 1616and now X.org crashes / the screen stays black / my laptop doesn't shutdown
1502properly. 1617properly.
1503</p> 1618</p>
1504 1619
1505<p> 1620<p>
1506<e>A:</e> This happens on some systems. You have to disable DynamicClocks. 1621<e>A:</e> This happens on some systems. You have to disable
1622<c>DynamicClocks</c>.
1507</p> 1623</p>
1508 1624
1509<p> 1625<p>
1510<e>Q:</e> I want to use suspend2, but it tells me my swap partition is too 1626<e>Q:</e> I want to use suspend2, but it tells me my swap partition is too
1511small. Resizing is not an option. 1627small. Resizing is not an option.
1512</p> 1628</p>
1513 1629
1514<p> 1630<p>
1515<e>A:</e> If there is enough free space on your system, you can use the 1631<e>A:</e> If there is enough free space on your system, you can use the
1516filewriter instead of the swapwriter. The <c>hibernate-script</c> supports it 1632filewriter instead of the swapwriter. The <c>hibernate-script</c> supports it
1517as well. More information can be found in 1633as well. More information can be found in
1518<path>/usr/src/linux/Documentation/power/suspend2.txt</path>. 1634<path>/usr/src/linux/Documentation/power/suspend2.txt</path>.
1519</p> 1635</p>
1520 1636
1523minutes! What am I doing wrong? 1639minutes! What am I doing wrong?
1524</p> 1640</p>
1525 1641
1526<p> 1642<p>
1527<e>A:</e> First follow your manufacturer's advice on how to charge the battery 1643<e>A:</e> First follow your manufacturer's advice on how to charge the battery
1528correctly. 1644correctly.
1529</p> 1645</p>
1530 1646
1531<p> 1647<p>
1532<e>Q:</e> The above didn't help. What should I do then? 1648<e>Q:</e> The above didn't help. What should I do then?
1533</p> 1649</p>
1550<p> 1666<p>
1551<e>Q:</e> My problem is not listed above. Where should I go next? 1667<e>Q:</e> My problem is not listed above. Where should I go next?
1552</p> 1668</p>
1553 1669
1554<p> 1670<p>
1555<e>A:</e> Don't fear to contact me, <mail link="fragfred@gmx.de">Dennis 1671<e>A:</e> Don't fear to contact me, <mail link="earthwings@gentoo.org">Dennis
1556Nienhüser</mail>, directly. 1672Nienhüser</mail>, directly. The <uri link="http://forums.gentoo.org">Gentoo
1673Forums</uri> are a good place to get help as well. If you prefer IRC, try the
1674<c>#gentoo-laptop</c> channel at <uri
1675link="irc://irc.freenode.net">irc.freenode.net</uri>.
1557</p> 1676</p>
1558 1677
1559</body> 1678</body>
1560</section> 1679</section>
1561</chapter> 1680</chapter>

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