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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 1.17 2006/02/12 11:53:08 nightmorph Exp $ --> 3<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/power-management-guide.xml,v 1.21 2006/08/17 00:45:29 rane 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="earthwings@gentoo.org">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>
9</author> 12</author>
10 13
11<abstract> 14<abstract>
12Power Management is the key to extend battery run time on mobile systems like 15Power Management is the key to extend battery run time on mobile systems like
13laptops. This guide assists you setting it up on your laptop. 16laptops. This guide assists you setting it up on your laptop.
15 18
16<!-- The content of this document is licensed under the CC-BY-SA license --> 19<!-- The content of this document is licensed under the CC-BY-SA license -->
17<!-- See http://creativecommons.org/licenses/by-sa/2.5 --> 20<!-- See http://creativecommons.org/licenses/by-sa/2.5 -->
18<license/> 21<license/>
19 22
20<version>1.26</version> 23<version>1.28</version>
21<date>2006-02-12</date> 24<date>2006-07-26</date>
22 25
23<chapter> 26<chapter>
24<title>Introduction</title> 27<title>Introduction</title>
25<section> 28<section>
26<body> 29<body>
34intelligent Power Management policies. 37intelligent Power Management policies.
35</p> 38</p>
36 39
37</body> 40</body>
38</section> 41</section>
39
40<section> 42<section>
41<title>A quick overview</title> 43<title>A Quick Overview</title>
42<body> 44<body>
43 45
44<p> 46<p>
45Please notice that this guide describes Power Management for <e>laptops</e>. 47Please notice that this guide describes Power Management for <e>laptops</e>.
46While some sections might also suite for <e>servers</e>, others do not and may 48While some sections might also suite for <e>servers</e>, others do not and may
52As this guide has become rather long, here's a short overview helping you to 54As this guide has become rather long, here's a short overview helping you to
53find your way through it. 55find your way through it.
54</p> 56</p>
55 57
56<p> 58<p>
57The <e>Prerequisites</e> chapter talks about some requirements that should be 59The <uri link="#doc_chap2">Prerequisites</uri> chapter talks about some
58met before any of the following device individual sections will work. This 60requirements that should be met before any of the following device individual
59includes BIOS settings, kernel configuration and some simplifications in user 61sections will work. This includes BIOS settings, kernel configuration and some
60land. The following three chapters focus on devices that typically consume 62simplifications in user land. The following three chapters focus on devices
61most energy - processor, display and hard drive. Each can be configured 63that typically consume most energy - processor, display and hard drive. Each
62seperately. <e>CPU Power Management</e> shows how to adjust the processor's 64can be configured seperately. <uri link="#doc_chap3">CPU Power Management</uri>
63frequency to save a maximum of energy whithout losing too much performance. A 65shows how to adjust the processor's frequency to save a maximum of energy
64few different tricks prevent your hard drive from working unnecessarily often 66without losing too much performance. A few different tricks prevent your hard
65in <e>Disk Power Management</e> (decreasing noise level as a nice side 67drive from working unnecessarily often in <uri link="#doc_chap5">Disk Power
66effect). Some notes on graphics cards, Wireless LAN and USB finish the device 68Management</uri> (decreasing noise level as a nice side effect). Some notes on
67section in <e>Power Management for other devices</e> while another chapter is 69graphics cards, Wireless LAN and USB finish the device section in <uri
68dedicated to the (rather experimental) <e>sleep states</e>. Last not least 70link="#doc_chap6">Power Management For Other Devices</uri> while another
69<e>Troubleshooting</e> lists common pitfalls. 71chapter is dedicated to the (rather experimental) <uri link="#doc_chap7">sleep
72states</uri>. Last not least <uri link="#doc_chap8">Troubleshooting</uri> lists
73common pitfalls.
70</p> 74</p>
71 75
72</body> 76</body>
73</section>
74
75<section> 77</section>
78<section>
76<title>Power Budget for each component</title> 79<title>Power Budget For Each Component</title>
77<body> 80<body>
78 81
79<figure link="/images/energy-budget.png" short="Which component consumes how 82<figure link="/images/energy-budget.png" short="Which component consumes how
80much energy?" caption="Power budget for each component"/> 83much energy?" caption="Power budget for each component"/>
81 84
96<section> 99<section>
97<body> 100<body>
98 101
99<p> 102<p>
100Before discussing the details of making individual devices Power Management 103Before discussing the details of making individual devices Power Management
101aware, make sure certain requirements are met. After controlling BIOS 104aware, make sure certain requirements are met. After controlling BIOS settings,
102settings, some kernel options want to be enabled - these are in short ACPI, 105some kernel options want to be enabled - these are in short ACPI, sleep states
103sleep states and CPU frequency scaling. As power saving most of the time comes 106and CPU frequency scaling. As power saving most of the time comes along with
104along with performance loss or increased latency, it should only be enabled 107performance loss or increased latency, it should only be enabled when running
105when running on batteries. That's where a new runlevel <e>battery</e> comes in 108on batteries. That's where a new runlevel <e>battery</e> comes in handy.
106handy.
107</p> 109</p>
108 110
109</body> 111</body>
110</section>
111<section> 112</section>
113<section>
112<title>The BIOS part</title> 114<title>The BIOS Part</title>
113<body> 115<body>
114 116
115<p> 117<p>
116First have a look into your BIOS Power Management settings. The best way is to 118First have a look into your BIOS Power Management settings. The best way is to
117combine BIOS and operating system policies, but for the moment it's better to 119combine BIOS and operating system policies, but for the moment it's better to
121</p> 123</p>
122 124
123</body> 125</body>
124</section> 126</section>
125<section> 127<section>
126<title>Setting USE flags</title> 128<title>Setting USE Flags</title>
127<body> 129<body>
128 130
129<p> 131<p>
130Please check that the <c>acpi</c> USE flag is set in 132Please check that the <c>acpi</c> USE flag is set in
131<path>/etc/make.conf</path>. Other USE flags that might be interesting for your 133<path>/etc/make.conf</path>. Other USE flags that might be interesting for your
132system are <c>apm</c>, <c>lm_sensors</c>, <c>nforce2</c>, <c>nvidia</c>, 134system are <c>apm</c>, <c>lm_sensors</c>, <c>nforce2</c>, <c>nvidia</c>,
133<c>pmu</c>. See <path>/usr/portage/profiles/use*.desc</path> for details. If 135<c>pmu</c>. See <path>/usr/portage/profiles/use*.desc</path> for details. If
134you forgot to set one of these flags, you can recompile affected packages using 136you forgot to set one of these flags, you can recompile affected packages using
135the <c>--newuse</c> flag in <c>emerge</c>, see <c>man 1 emerge</c>. 137the <c>--newuse</c> flag in <c>emerge</c>, see <c>man emerge</c>.
136</p> 138</p>
137 139
138</body> 140</body>
139</section>
140<section> 141</section>
142<section>
141<title>Configuring the kernel</title> 143<title>Configuring The Kernel</title>
142<body> 144<body>
143 145
144<p> 146<p>
145ACPI (Advanced Configuration and Power Interface) support in the kernel is 147ACPI (Advanced Configuration and Power Interface) support in the kernel is
146still work in progress. Using a recent kernel will make sure you'll get the 148still work in progress. Using a recent kernel will make sure you'll get the
147most out of it. 149most out of it.
148</p> 150</p>
149 151
150<p> 152<p>
151There are different kernel sources in Portage. I'd recommend using 153There are different kernel sources in Portage. I'd recommend using
152<c>gentoo-sources</c> or <c>suspend2-sources</c>. The latter contains patches 154<c>gentoo-sources</c> or <c>suspend2-sources</c>. The latter contains patches
153for Software Suspend 2, see the chapter about sleep states for details. When 155for Software Suspend 2, see the chapter about <uri link="#doc_chap7">sleep
154configuring the kernel, activate at least these options: 156states</uri> for more details. When configuring the kernel, activate at least
157these options:
155</p> 158</p>
156 159
157<pre caption="Minimum kernel setup for Power Management (Kernel 2.6)"> 160<pre caption="Minimum kernel setup for Power Management (Kernel 2.6)">
158Power Management Options ---&gt; 161Power Management Options ---&gt;
159 [*] Power Management Support 162 [*] Power Management Support
176 &lt; &gt; Toshiba Laptop Extras 179 &lt; &gt; Toshiba Laptop Extras
177 (0) Disable ACPI for systems before Jan 1st this year 180 (0) Disable ACPI for systems before Jan 1st this year
178 [ ] Debug Statements 181 [ ] Debug Statements
179 [*] Power Management Timer Support 182 [*] Power Management Timer Support
180 &lt; &gt; ACPI0004,PNP0A05 and PNP0A06 Container Driver (EXPERIMENTAL) 183 &lt; &gt; ACPI0004,PNP0A05 and PNP0A06 Container Driver (EXPERIMENTAL)
181 184
182 CPU Frequency Scaling ---&gt; 185 CPU Frequency Scaling ---&gt;
183 [*] CPU Frequency scaling 186 [*] CPU Frequency scaling
184 [ ] Enable CPUfreq debugging 187 [ ] Enable CPUfreq debugging
185 &lt; &gt; CPU frequency translation statistics 188 &lt; &gt; CPU frequency translation statistics
186 [ ] CPU frequency translation statistics details 189 [ ] CPU frequency translation statistics details
199(see below). If you own an ASUS, Medion, IBM Thinkpad or Toshiba laptop, enable 202(see below). If you own an ASUS, Medion, IBM Thinkpad or Toshiba laptop, enable
200the appropriate section. 203the appropriate section.
201</p> 204</p>
202 205
203<p> 206<p>
204The kernel has to know how to enable CPU frequency scaling on your processor. As 207The kernel has to know how to enable CPU frequency scaling on your processor.
205each type of CPU has a different interface, you've got to choose the right 208As each type of CPU has a different interface, you've got to choose the right
206driver for your processor. Be careful here - enabling <e>Intel Pentium 4 clock 209driver for your processor. Be careful here - enabling <c>Intel Pentium 4 clock
207modulation</e> on a Pentium M system will lead to strange results for example. 210modulation</c> on a Pentium M system will lead to strange results for example.
208Consult the kernel documentation if you're unsure which one to take. 211Consult the kernel documentation if you're unsure which one to take.
209</p> 212</p>
210 213
211<p> 214<p>
212Compile your kernel, make sure the right modules get loaded at startup and boot 215Compile your kernel, make sure the right modules get loaded at startup and boot
213into your new ACPI-enabled kernel. Next run <c>emerge sys-power/acpid</c> to get 216into your new ACPI-enabled kernel. Next run <c>emerge sys-power/acpid</c> to
214the acpi daemon. This one informs you about events like switching from AC to 217get the acpi daemon. This one informs you about events like switching from AC
215battery or closing the lid. Make sure the modules are loaded if you didn't 218to battery or closing the lid. Make sure the modules are loaded if you didn't
216compile them into the kernel and start acpid by executing 219compile them into the kernel and start acpid by executing <c>/etc/init.d/acpid
217<c>/etc/init.d/acpid start</c>. Run <c>rc-update add acpid default</c> to load 220start</c>. Run <c>rc-update add acpid default</c> to load it on startup. You'll
218it on startup. You'll soon see how to use it. 221soon see how to use it.
219</p> 222</p>
220 223
221<pre caption="Installing acpid"> 224<pre caption="Installing acpid">
222# <i>emerge sys-power/acpid</i> 225# <i>emerge sys-power/acpid</i>
223# <i>/etc/init.d/acpid start</i> 226# <i>/etc/init.d/acpid start</i>
225</pre> 228</pre>
226 229
227</body> 230</body>
228</section> 231</section>
229<section> 232<section>
230<title>Creating a "battery" runlevel</title> 233<title>Creating A "battery" Runlevel</title>
231<body> 234<body>
232 235
233<p> 236<p>
234The default policy will be to enable Power Management only when needed - 237The default policy will be to enable Power Management only when needed -
235running on batteries. To make the switch between AC and battery convenient, 238running on batteries. To make the switch between AC and battery convenient,
236create a runlevel <e>battery</e> that holds all the scripts starting and 239create a runlevel <c>battery</c> that holds all the scripts starting and
237stopping Power Management. 240stopping Power Management.
238</p> 241</p>
239 242
240<note> 243<note>
241You can safely skip this section if you don't like the idea of having another 244You can safely skip this section if you don't like the idea of having another
242runlevel. However, skipping this step will make the rest a bit trickier to set 245runlevel. However, skipping this step will make the rest a bit trickier to set
243up. The next sections assume a runlevel <e>battery</e> exists. 246up. The next sections assume a runlevel <c>battery</c> exists.
244</note> 247</note>
245 248
246<pre caption="Creating a battery runlevel"> 249<pre caption="Creating a battery runlevel">
247# <i>cd /etc/runlevels</i> 250# <i>cd /etc/runlevels</i>
248# <i>cp -a default battery</i> 251# <i>cp -a default battery</i>
249</pre> 252</pre>
250 253
251<p> 254<p>
252Finished. Your new runlevel <e>battery</e> contains everything like 255Finished. Your new runlevel <c>battery</c> contains everything like
253<e>default</e>, but there is no automatic switch between both yet. Time to 256<c>default</c>, but there is no automatic switch between both yet. Time to
254change it. 257change it.
255</p> 258</p>
256 259
257</body> 260</body>
258</section> 261</section>
259<section> 262<section>
260<title>Reacting on ACPI events</title> 263<title>Reacting On ACPI Events</title>
261<body> 264<body>
262 265
263<p> 266<p>
264Typical ACPI events are closing the lid, changing the power source or pressing 267Typical ACPI events are closing the lid, changing the power source or pressing
265the sleep button. An important event is changing the power source, which should 268the sleep button. An important event is changing the power source, which should
272<c>on_ac_power</c> command from <c>sys-power/powermgmt-base</c> - make sure the 275<c>on_ac_power</c> command from <c>sys-power/powermgmt-base</c> - make sure the
273package is installed on your system. 276package is installed on your system.
274</p> 277</p>
275 278
276<pre caption="Installing powermgt-base"> 279<pre caption="Installing powermgt-base">
277<i># emerge powermgmt-base</i> 280# <i>emerge powermgmt-base</i>
278</pre> 281</pre>
279 282
280<p> 283<p>
281You are now able to determine the power source by executing 284You are now able to determine the power source by executing <c>on_ac_power
282<c>on_ac_power &amp;&amp; echo AC available || echo Running on batteries</c> in 285&amp;&amp; echo AC available || echo Running on batteries</c> in a shell. The
283a shell. The script below is responsible for changing runlevels. Save it as 286script below is responsible for changing runlevels. Save it as
284<path>/etc/acpi/actions/pmg_switch_runlevel.sh</path>. 287<path>/etc/acpi/actions/pmg_switch_runlevel.sh</path>.
285</p> 288</p>
286 289
287<pre caption="/etc/acpi/actions/pmg_switch_runlevel.sh"> 290<pre caption="/etc/acpi/actions/pmg_switch_runlevel.sh">
288#!/bin/bash 291#!/bin/bash
305 exit 1 308 exit 1
306fi 309fi
307 310
308if on_ac_power 311if on_ac_power
309then 312then
310 if [[ "$(cat /var/lib/init.d/softlevel)" != "${RUNLEVEL_AC}" ]] 313 if [[ "$(&lt;/var/lib/init.d/softlevel)" != "${RUNLEVEL_AC}" ]]
311 then 314 then
312 logger "Switching to ${RUNLEVEL_AC} runlevel" 315 logger "Switching to ${RUNLEVEL_AC} runlevel"
313 /sbin/rc ${RUNLEVEL_AC} 316 /sbin/rc ${RUNLEVEL_AC}
314 fi 317 fi
315elif [[ "$(cat /var/lib/init.d/softlevel)" != "${RUNLEVEL_BATTERY}" ]] 318elif [[ "$(&lt;/var/lib/init.d/softlevel)" != "${RUNLEVEL_BATTERY}" ]]
316then 319then
317 logger "Switching to ${RUNLEVEL_BATTERY} runlevel" 320 logger "Switching to ${RUNLEVEL_BATTERY} runlevel"
318 /sbin/rc ${RUNLEVEL_BATTERY} 321 /sbin/rc ${RUNLEVEL_BATTERY}
319fi 322fi
320</pre> 323</pre>
323Dont forget to run <c>chmod +x /etc/acpi/actions/pmg_switch_runlevel.sh</c> to 326Dont forget to run <c>chmod +x /etc/acpi/actions/pmg_switch_runlevel.sh</c> to
324make the script executable. The last thing that needs to be done is calling the 327make the script executable. The last thing that needs to be done is calling the
325script whenever the power source changes. That's done by catching ACPI events 328script whenever the power source changes. That's done by catching ACPI events
326with the help of <c>acpid</c>. First you need to know which events are 329with the help of <c>acpid</c>. First you need to know which events are
327generated when the power source changes. The events are called 330generated when the power source changes. The events are called
328<e>ac_adapter</e> and <e>battery</e> on most laptops, but it might be different 331<c>ac_adapter</c> and <c>battery</c> on most laptops, but it might be different
329on yours. 332on yours.
330</p> 333</p>
331 334
332<pre caption="Determining ACPI events for changing the power source"> 335<pre caption="Determining ACPI events for changing the power source">
333<i># tail -f /var/log/acpid | grep "received event"</i> 336# <i>tail -f /var/log/acpid | grep "received event"</i>
334</pre> 337</pre>
335 338
336<p> 339<p>
337Run the command above and pull the power cable. You should see something 340Run the command above and pull the power cable. You should see something like
338like this: 341this:
339</p> 342</p>
340 343
341<pre caption="Sample output for power source changes"> 344<pre caption="Sample output for power source changes">
342[Tue Sep 20 17:39:06 2005] received event "ac_adapter AC 00000080 00000000" 345[Tue Sep 20 17:39:06 2005] received event "ac_adapter AC 00000080 00000000"
343[Tue Sep 20 17:39:06 2005] received event "battery BAT0 00000080 00000001" 346[Tue Sep 20 17:39:06 2005] received event "battery BAT0 00000080 00000001"
344</pre> 347</pre>
345 348
346<p> 349<p>
347The interesting part is the quoted string after <e>received event</e>. It will 350The interesting part is the quoted string after <c>received event</c>. It will
348be matched by the event line in the files you are going to create below. Don't 351be matched by the event line in the files you are going to create below. Don't
349worry if your system generates multiple events or always the same. As long as 352worry if your system generates multiple events or always the same. As long as
350any event is generated, runlevel changing will work. 353any event is generated, runlevel changing will work.
351</p> 354</p>
352 355
367<p> 370<p>
368Finally acpid has to be restarted to recognize the changes. 371Finally acpid has to be restarted to recognize the changes.
369</p> 372</p>
370 373
371<pre caption="Finishing runlevel switching with acpid"> 374<pre caption="Finishing runlevel switching with acpid">
372<i># /etc/init.d/acpid restart</i> 375# <i>/etc/init.d/acpid restart</i>
373</pre> 376</pre>
374 377
375<p> 378<p>
376Give it a try: Plug AC in and out and watch syslog for the "Switching to AC 379Give it a try: Plug AC in and out and watch syslog for the "Switching to AC
377mode" or "Switching to battery mode" messages. See the Troubleshooting 380mode" or "Switching to battery mode" messages. See the <uri
378section if the script is not able to detect the power source correctly. 381link="#doc_chap8">Troubleshooting section</uri> if the script is not able to
382detect the power source correctly.
379</p> 383</p>
380 384
381<p> 385<p>
382Due to the nature of the event mechanism, your laptop will boot into runlevel 386Due to the nature of the event mechanism, your laptop will boot into runlevel
383<e>default</e> regardless of the AC/battery state. This is fine when running 387<c>default</c> regardless of the AC/battery state. This is fine when running
384from AC, but we'd like to boot into the battery runlevel otherwise. One 388from AC, but we'd like to boot into the battery runlevel otherwise. One
385solution would be to add another entry to the boot loader with the parameter 389solution would be to add another entry to the boot loader with the parameter
386<c>softlevel=battery</c>, but it's likely to forget choosing it. A better way 390<c>softlevel=battery</c>, but it's likely to forget choosing it. A better way
387is faking an ACPI event in the end of the boot process and letting 391is faking an ACPI event in the end of the boot process and letting
388<path>pmg_switch_runlevel.sh</path> script decide whether a 392<path>pmg_switch_runlevel.sh</path> script decide whether a runlevel change is
389runlevel change is necessary. Open <path>/etc/conf.d/local.start</path> in your 393necessary. Open <path>/etc/conf.d/local.start</path> in your favourite editor
390favourite editor and add these lines: 394and add these lines:
391</p> 395</p>
392 396
393<pre caption="Runlevel adjustment at boot time by editing local.start"> 397<pre caption="Runlevel adjustment at boot time by editing local.start">
394<comment># Fake acpi event to switch runlevel if running on batteries</comment> 398<comment># Fake acpi event to switch runlevel if running on batteries</comment>
395/etc/acpi/actions/pmg_switch_runlevel.sh "battery/battery" 399/etc/acpi/actions/pmg_switch_runlevel.sh "battery/battery"
396</pre> 400</pre>
397 401
398<p> 402<p>
399Prepared like this you can activate Power Management policies for individual 403Prepared like this you can activate Power Management policies for individual
400devices. 404devices.
401</p> 405</p>
402 406
403</body> 407</body>
404</section> 408</section>
416decrease. 420decrease.
417</p> 421</p>
418 422
419</body> 423</body>
420</section> 424</section>
421
422<section> 425<section>
423<title>Some technical terms</title> 426<title>Some Technical Terms</title>
424<body> 427<body>
425 428
426<p> 429<p>
427CPU frequency scaling brings up some technical terms that might be unknown to 430CPU frequency scaling brings up some technical terms that might be unknown to
428you. Here's a quick introduction. 431you. Here's a quick introduction.
429</p> 432</p>
430 433
431<p> 434<p>
432First of all, the kernel has to be able to change the processor's frequency. 435First of all, the kernel has to be able to change the processor's frequency.
433The <e>CPUfreq processor driver</e> knows the commands to do it on your CPU. 436The <b>CPUfreq processor driver</b> knows the commands to do it on your CPU.
434Thus it's important to choose the right one in your kernel. You should 437Thus it's important to choose the right one in your kernel. You should already
435already have done it above. Once the kernel knows how to change frequencies, 438have done it above. Once the kernel knows how to change frequencies, it has to
436it has to know which frequency it should set. This is done according to the 439know which frequency it should set. This is done according to the <b>policy</b>
437<e>policy</e> which consists of a <e>CPUfreq policy</e> and a 440which consists of a <b>CPUfreq policy</b> and a <b>governor</b>. A CPUfreq
438<e>governor</e>. A CPUfreq policy are just two numbers which define a range 441policy are just two numbers which define a range the frequency has to stay
439the frequency has to stay between - minimal and maximal frequency. The 442between - minimal and maximal frequency. The governor now decides which of the
440governor now decides which of the available frequencies in between minimal 443available frequencies in between minimal and maximal frequency to choose. For
441and maximal frequency to choose. For example, the <e>powersave governor</e> 444example, the <b>powersave governor</b> always chooses the lowest frequency
442always chooses the lowest frequency available, the <e>performance 445available, the <b>performance governor</b> the highest one. The <b>userspace
443governor</e> the highest one. The <e>userspace governor</e> makes no decision 446governor</b> makes no decision but chooses whatever the user (or a program in
444but chooses whatever the user (or a program in userspace) wants - which means 447userspace) wants - which means it reads the frequency from
445it reads the frequency from
446<path>/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed</path>. 448<path>/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed</path>.
447</p> 449</p>
448 450
449<p> 451<p>
450This doesn't sound like dynamic frequency changes yet and in fact it isn't. 452This doesn't sound like dynamic frequency changes yet and in fact it isn't.
451Dynamics however can be accomplished with various approaches. For example, 453Dynamics however can be accomplished with various approaches. For example, the
452the <e>ondemand governor</e> makes its decisions depending on the current CPU 454<b>ondemand governor</b> makes its decisions depending on the current CPU load.
453load. The same is done by various userland tools like <c>cpudyn</c>, 455The same is done by various userland tools like <c>cpudyn</c>, <c>cpufreqd</c>,
454<c>cpufreqd</c>, <c>powernowd</c> and many more. ACPI events can be used to 456<c>powernowd</c> and many more. ACPI events can be used to enable or disable
455enable or disable dynamic frequency changes depending on power source. 457dynamic frequency changes depending on power source.
456</p> 458</p>
457 459
458</body> 460</body>
459</section>
460<section> 461</section>
462<section>
461<title>Setting the frequency manually</title> 463<title>Setting The Frequency Manually</title>
462<body> 464<body>
463 465
464<p> 466<p>
465Decreasing CPU speed and voltage has two advantages: On the one hand less 467Decreasing CPU speed and voltage has two advantages: On the one hand less
466energy is consumed, on the other hand there is thermal improvement as your 468energy is consumed, on the other hand there is thermal improvement as your
469between performance loss and energy saving. 471between performance loss and energy saving.
470</p> 472</p>
471 473
472<note> 474<note>
473Not every laptop supports frequency scaling. If unsure, have a look at the list 475Not every laptop supports frequency scaling. If unsure, have a look at the list
474of supported processors in the <e>Troubleshooting</e> section to verify your's 476of supported processors in the <uri link="#doc_chap8">Troubleshooting</uri>
475is supported. 477section to verify yours is supported.
476</note> 478</note>
477 479
478<p> 480<p>
479It's time to test whether CPU frequency changing works. Let's install another 481It's time to test whether CPU frequency changing works. Let's install another
480tool which is very handy for debugging purposes: <c>sys-power/cpufrequtils</c> 482tool which is very handy for debugging purposes: <c>sys-power/cpufrequtils</c>
506 508
507<p> 509<p>
508Now play around with <c>cpufreq-set</c> to make sure frequency switching works. 510Now play around with <c>cpufreq-set</c> to make sure frequency switching works.
509Run <c>cpufreq-set -g ondemand</c> for example to activate the ondemand 511Run <c>cpufreq-set -g ondemand</c> for example to activate the ondemand
510governor and verify the change with <c>cpufreq-info</c>. If it doesn't work as 512governor and verify the change with <c>cpufreq-info</c>. If it doesn't work as
511expected, you might find help in the Troubleshooting section in the end of this 513expected, you might find help in the <uri link="#doc_chap8">Troubleshooting
512guide. 514section</uri> in the end of this guide.
513</p> 515</p>
514 516
515</body> 517</body>
516</section> 518</section>
517<section> 519<section>
520 522
521<p> 523<p>
522The above is quite nice, but not doable in daily life. Better let your system 524The above is quite nice, but not doable in daily life. Better let your system
523set the appropriate frequency automatically. There are many different 525set the appropriate frequency automatically. There are many different
524approaches to do this. The following table gives a quick overview to help you 526approaches to do this. The following table gives a quick overview to help you
525decide on one of them. It's roughly seperated in three categories 527decide on one of them. It's roughly separated in three categories <b>kernel</b>
526<e>kernel</e> for approaches that only need kernel support, <e>daemon</e> for 528for approaches that only need kernel support, <b>daemon</b> for programs that
527programs that run in the background and <e>graphical</e> for programs that 529run in the background and <b>graphical</b> for programs that provide a GUI for
528provide a GUI for easy configuration and changes. 530easy configuration and changes.
529</p> 531</p>
530 532
531<table> 533<table>
532<tr> 534<tr>
533 <th>Name</th> 535 <th>Name</th>
602 Supports SMP. 604 Supports SMP.
603 </ti> 605 </ti>
604</tr> 606</tr>
605<tr> 607<tr>
606 <ti> 608 <ti>
609 <uri
607 <uri link="http://fatcat.ftj.agh.edu.pl/~nelchael/index.php?cat=projs&amp;subcat=ncpufreqd&amp;language=en">ncpufreqd</uri> 610 link="http://fatcat.ftj.agh.edu.pl/~nelchael/index.php?cat=projs&amp;subcat=ncpufreqd&amp;language=en">ncpufreqd</uri>
608 </ti> 611 </ti>
609 <ti>Daemon</ti> 612 <ti>Daemon</ti>
610 <ti>Temperature</ti> 613 <ti>Temperature</ti>
611 <ti>None</ti> 614 <ti>None</ti>
612 <ti>Powersave, performance</ti> 615 <ti>Powersave, performance</ti>
652 655
653<p> 656<p>
654While 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
655glance, 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
656between two frequencies all the time or wasting energy when setting frequency 659between two frequencies all the time or wasting energy when setting frequency
657to an unnecessary high level. 660to an unnecessary high level.
658</p> 661</p>
659 662
660<p> 663<p>
661Which 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>:
662</p> 665</p>
676<pre caption="/etc/cpufreqd.conf (cpufreqd-2.0.0 and later)"> 679<pre caption="/etc/cpufreqd.conf (cpufreqd-2.0.0 and later)">
677[General] 680[General]
678pidfile=/var/run/cpufreqd.pid 681pidfile=/var/run/cpufreqd.pid
679poll_interval=3 682poll_interval=3
680enable_plugins=acpi_ac, acpi_battery 683enable_plugins=acpi_ac, acpi_battery
684enable_remote=1
685remote_group=wheel
681verbosity=5 686verbosity=5
682[/General] 687[/General]
683 688
684[Profile] 689[Profile]
685name=ondemand 690name=ondemand
728profile=ondemand 733profile=ondemand
729[/Rule] 734[/Rule]
730</pre> 735</pre>
731 736
732<p> 737<p>
733Now 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
734<e>battery</e> runlevel as well. 739<c>battery</c> runlevel as well.
735</p> 740</p>
736 741
737<pre caption="Starting cpufreqd"> 742<pre caption="Starting cpufreqd">
738# <i>rc-update add cpufreqd default battery</i> 743# <i>rc-update add cpufreqd default battery</i>
739# <i>rc</i> 744# <i>rc</i>
740</pre> 745</pre>
741 746
742<p> 747<p>
743Sometimes it can be desirable to select another policy than the daemon chooses, 748Sometimes it can be desirable to select another policy than the daemon chooses,
744for example when battery power is low, but you know that AC will be available 749for example when battery power is low, but you know that AC will be available
745soon. In that case you can turn on cpufreqd's manual mode with 750soon. In that case you can turn on cpufreqd's manual mode with <c>cpufreqd-set
746<c>cpufreqd-set manual</c> and select one of your configured policies (as 751manual</c> and select one of your configured policies (as listed by
747listed by <c>cpufreqd-get</c>). You can leave manual mode by executing 752<c>cpufreqd-get</c>). You can leave manual mode by executing <c>cpufreqd-set
748<c>cpufreqd-set dynamic</c>. 753dynamic</c>.
749</p> 754</p>
750 755
751<warn> 756<warn>
752Do 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
753confusion like switching between two frequencies all the time. 758confusion like switching between two frequencies all the time.
754</warn> 759</warn>
755 760
756</body> 761</body>
757</section> 762</section>
758
759<section> 763<section>
760<title>Verifying the result</title> 764<title>Verifying the result</title>
761
762<body> 765<body>
763 766
764<p> 767<p>
765The 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
766do so is monitoring CPU speed while working with your laptop: 769do so is monitoring CPU speed while working with your laptop:
769<pre caption="Monitoring CPU speed"> 772<pre caption="Monitoring CPU speed">
770# <i>watch grep \"cpu MHz\" /proc/cpuinfo</i> 773# <i>watch grep \"cpu MHz\" /proc/cpuinfo</i>
771</pre> 774</pre>
772 775
773<p> 776<p>
774If <path>/proc/cpuinfo</path> doesn't get updated (see Troubleshooting), 777If <path>/proc/cpuinfo</path> doesn't get updated (see <uri
775monitor the CPU frequency with: 778link="#doc_chap8">Troubleshooting</uri>), monitor the CPU frequency with:
776</p> 779</p>
777 780
778<pre caption="Alternative CPU speed monitoring"> 781<pre caption="Alternative CPU speed monitoring">
779# <i>watch x86info -mhz</i> 782# <i>watch x86info -mhz</i>
780</pre> 783</pre>
781 784
782<p> 785<p>
783Depending 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
784no 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
785set 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
786information about what's happening reported to syslog. 789additional information about what's happening reported to <c>syslog</c>.
787</p> 790</p>
788 791
789</body> 792</body>
790</section> 793</section>
791</chapter> 794</chapter>
794<title>LCD Power Management</title> 797<title>LCD Power Management</title>
795<section> 798<section>
796<body> 799<body>
797 800
798<p> 801<p>
799As 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
800consumes 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
801CPU'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
802needed, 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
803possibility to control the backlight dimming. 806offer the possibility to control the backlight dimming.
804</p> 807</p>
805 808
806</body> 809</body>
807</section> 810</section>
808<section> 811<section>
810<body> 813<body>
811 814
812<p> 815<p>
813The first thing to check is the standby/suspend/off timings of the display. As 816The first thing to check is the standby/suspend/off timings of the display. As
814this depends heavily on your windowmanager, I'll let you figure it out 817this depends heavily on your windowmanager, I'll let you figure it out
815yourself. Just two common places: Blanking the terminal can be done with 818yourself. Just two common places: Blanking the terminal can be done with
816<c>setterm -blank &lt;number-of-minutesM&gt;</c>, <c>setterm -powersave on</c> 819<c>setterm -blank &lt;number-of-minutesM&gt;</c>, <c>setterm -powersave on</c>
817and <c>setterm -powerdown &lt;number-of-minutesM&gt;</c>. For X.org, modify 820and <c>setterm -powerdown &lt;number-of-minutesM&gt;</c>. For X.org, modify
818<path>/etc/X11/xorg.conf</path> similar to this: 821<path>/etc/X11/xorg.conf</path> similar to this:
819</p> 822</p>
820 823
849<body> 852<body>
850 853
851<p> 854<p>
852Probably 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
853dimming 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
854battery 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
855should work on most IBM Thinkpads and Toshiba laptops. You've got to enable the 858should work on most IBM Thinkpads and Toshiba laptops. You've got to enable the
856appropriate option in your kernel (IBM Thinkpads only). For Toshiba laptops, install 859appropriate option in your kernel (IBM Thinkpads only). For Toshiba laptops,
857<c>app-laptop/acpitool</c> and skip configuration of ibm_acpi as described below. 860install <c>app-laptop/acpitool</c> and skip configuration of <c>ibm_acpi</c> as
861described below.
858</p> 862</p>
859 863
860<warn> 864<warn>
861Support for setting brightness is marked experimental in ibm-acpi. It accesses 865Support for setting brightness is marked experimental in ibm-acpi. It accesses
862hardware 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
868with the experimental parameter. 872with the experimental parameter.
869</p> 873</p>
870 874
871<pre caption="automatically loading the ibm_acpi module"> 875<pre caption="automatically loading the ibm_acpi module">
872<comment>(Please read the warnings above before doing this!)</comment> 876<comment>(Please read the warnings above before doing this!)</comment>
873<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>
874<i># /sbin/modules-update</i> 878# <i>/sbin/modules-update</i>
875<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>
876<i># modprobe ibm_acpi</i> 880# <i>modprobe ibm_acpi</i>
877</pre> 881</pre>
878 882
879<p> 883<p>
880This should work without error messages and a file 884This should work without error messages and a file
881<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
882module. An init script will take care of choosing the brightness according 886module. An init script will take care of choosing the brightness according to
883to the power source. 887the power source.
884</p> 888</p>
885 889
886<pre caption="/etc/conf.d/lcd-brightness"> 890<pre caption="/etc/conf.d/lcd-brightness">
887<comment># See /proc/acpi/ibm/brightness for available values</comment> 891<comment># See /proc/acpi/ibm/brightness for available values</comment>
888<comment># Please read /usr/src/linux/Documentation/ibm-acpi.txt</comment> 892<comment># Please read /usr/src/linux/Documentation/ibm-acpi.txt</comment>
935When 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
936battery runlevel. 940battery runlevel.
937</p> 941</p>
938 942
939<pre caption="Enabling automatic brightness adjustment"> 943<pre caption="Enabling automatic brightness adjustment">
940<i># chmod +x /etc/init.d/lcd-brightness</i> 944# <i>chmod +x /etc/init.d/lcd-brightness</i>
941<i># rc-update add lcd-brightness battery</i> 945# <i>rc-update add lcd-brightness battery</i>
942<i># rc</i> 946# <i>rc</i>
943</pre> 947</pre>
944 948
945</body> 949</body>
946</section> 950</section>
947</chapter> 951</chapter>
948 952
949<chapter> 953<chapter>
950<title>Disk Power Management</title> 954<title>Disk Power Management</title>
951<section> 955<section>
952<body> 956<body>
957
953<p> 958<p>
954Hard disks consume less energy in sleep mode. Therefore it makes sense to 959Hard disks consume less energy in sleep mode. Therefore it makes sense to
955activate power saving features whenever the hard disk is not used for a certain 960activate power saving features whenever the hard disk is not used for a certain
956amount of time. I'll show you two alternative possibilities to do it. First, 961amount of time. I'll show you two alternative possibilities to do it. First,
957laptop-mode will save most energy due to several measures which prevent or at 962laptop-mode will save most energy due to several measures which prevent or at
958least delay write accesses. The drawback is that due to the delayed write 963least delay write accesses. The drawback is that due to the delayed write
959accesses a power outage or kernel crash will be more dangerous for data loss. 964accesses a power outage or kernel crash will be more dangerous for data loss.
960If you don't like this, you have to make sure that there are no processes which 965If you don't like this, you have to make sure that there are no processes which
961write to your hard disk frequently. Afterwards you can enable power saving 966write to your hard disk frequently. Afterwards you can enable power saving
962features of your hard disk with hdparm as the second alternative. 967features of your hard disk with <c>hdparm</c> as the second alternative.
963</p> 968</p>
964 969
965</body> 970</body>
966</section> 971</section>
967
968<section> 972<section>
969<title>Increasing idle time - laptop-mode</title> 973<title>Increasing idle time - laptop-mode</title>
970<body> 974<body>
971 975
972<p> 976<p>
973Recent kernels (2.6.6 and greater, recent 2.4 ones and others with patches) 977Recent kernels (2.6.6 and greater, recent 2.4 ones and others with patches)
974include the so-called <e>laptop-mode</e>. When activated, dirty buffers are 978include the so-called <c>laptop-mode</c>. When activated, dirty buffers are
975written to disk on read calls or after 10 minutes (instead of 30 seconds). This 979written to disk on read calls or after 10 minutes (instead of 30 seconds). This
976minimizes the time the hard disk needs to be spun up. 980minimizes the time the hard disk needs to be spun up.
977</p> 981</p>
978 982
979<pre caption="Automated start of laptop-mode"> 983<pre caption="Automated start of laptop-mode">
990<p> 994<p>
991Recent versions (1.11 and later) of laptop-mode-tools include a new tool 995Recent versions (1.11 and later) of laptop-mode-tools include a new tool
992<c>lm-profiler</c>. It will monitor your system's disk usage and running 996<c>lm-profiler</c>. It will monitor your system's disk usage and running
993network services and suggests to disable unneeded ones. You can either disable 997network services and suggests to disable unneeded ones. You can either disable
994them through laptop-mode-tools builtin runlevel support (which will be reverted 998them through laptop-mode-tools builtin runlevel support (which will be reverted
995by Gentoo's <c>/sbin/rc</c>) or use your <e>default</e>/<e>battery</e> 999by Gentoo's <c>/sbin/rc</c>) or use your <c>default</c>/<c>battery</c>
996runlevels (recommended). 1000runlevels (recommended).
997</p> 1001</p>
998 1002
999<pre caption="Sample output from running lm-profiler"> 1003<pre caption="Sample output from running lm-profiler">
1000# lm-profiler 1004# <i>lm-profiler</i>
1001Profiling session started. 1005Profiling session started.
1002Time remaining: 600 seconds 1006Time remaining: 600 seconds
1003[4296896.602000] amarokapp 1007[4296896.602000] amarokapp
1004Time remaining: 599 seconds 1008Time remaining: 599 seconds
1005[4296897.714000] sort 1009[4296897.714000] sort
1017<pre caption="lm-profiler suggests to disable some services"> 1021<pre caption="lm-profiler suggests to disable some services">
1018Program: "atd" 1022Program: "atd"
1019Reason: standard recommendation (program may not be running) 1023Reason: standard recommendation (program may not be running)
1020Init script: /etc/init.d/atd (GUESSED) 1024Init script: /etc/init.d/atd (GUESSED)
1021 1025
1022Do you want to disable this service in battery mode? [y/N]: n 1026Do you want to disable this service in battery mode? [y/N]: <i>n</i>
1023</pre> 1027</pre>
1024 1028
1025<p> 1029<p>
1026To disable atd as suggested in the example above, you would run <c>rc-update 1030To disable atd as suggested in the example above, you would run <c>rc-update
1027del atd battery</c>. Be careful not to disable services that are needed for 1031del atd battery</c>. Be careful not to disable services that are needed for
1028your system to run properly - lm-profiler is likely to generate some false 1032your system to run properly - <c>lm-profiler</c> is likely to generate some
1029positives. Do not disable a service if you are unsure whether it's needed. 1033false positives. Do not disable a service if you are unsure whether it's
1034needed.
1030</p> 1035</p>
1031 1036
1032</body> 1037</body>
1033</section>
1034
1035<section> 1038</section>
1039<section>
1036<title>Limiting write accesses</title> 1040<title>Limiting Write Accesses</title>
1037<body> 1041<body>
1038 1042
1039<p> 1043<p>
1040If you don't want to use laptop-mode, you must take special care to disable 1044If you don't want to use laptop-mode, you must take special care to disable
1041services that write to your disk frequently - <c>syslogd</c> is a good 1045services that write to your disk frequently - <c>syslogd</c> is a good
1042candidate, for example. You probably don't want to shut it down completely, but 1046candidate, for example. You probably don't want to shut it down completely, but
1043it's possible to modify the config file so that "unnecessary" things don't get 1047it's possible to modify the config file so that "unnecessary" things don't get
1044logged and thus don't create disk traffic. Cups writes to disk periodically, so 1048logged and thus don't create disk traffic. <c>Cups</c> writes to disk
1045consider shutting it down and only enable it manually when needed. 1049periodically, so consider shutting it down and only enable it manually when
1050needed.
1046</p> 1051</p>
1047 1052
1048<pre caption="Disabling cups in battery mode"> 1053<pre caption="Disabling cups in battery mode">
1049# <i>rc-update del cupsd battery</i> 1054# <i>rc-update del cupsd battery</i>
1050</pre> 1055</pre>
1055hdparm. 1060hdparm.
1056</p> 1061</p>
1057 1062
1058</body> 1063</body>
1059</section> 1064</section>
1060
1061<section> 1065<section>
1062<title>hdparm</title> 1066<title>hdparm</title>
1063<body> 1067<body>
1064 1068
1065<p> 1069<p>
1066The second possibility is using a small script and hdparm. Skip this if you 1070The second possibility is using a small script and <c>hdparm</c>. Skip this if
1067are using laptop-mode. Otherwise, create <path>/etc/init.d/pmg_hda</path>: 1071you are using laptop-mode. Otherwise, create <path>/etc/init.d/pmg_hda</path>:
1068</p> 1072</p>
1069 1073
1070<pre caption="Using hdparm for disk standby"> 1074<pre caption="Using hdparm for disk standby">
1071#!/sbin/runscript 1075#!/sbin/runscript
1072 1076
1103small values might wear out your drive and lose warranty. 1107small values might wear out your drive and lose warranty.
1104</impo> 1108</impo>
1105 1109
1106</body> 1110</body>
1107</section> 1111</section>
1108
1109<section> 1112<section>
1110<title>Other tricks</title> 1113<title>Other tricks</title>
1111<body> 1114<body>
1112 1115
1113<p> 1116<p>
1116heavily, otherwise you'll be in big problems. 1119heavily, otherwise you'll be in big problems.
1117</p> 1120</p>
1118 1121
1119<p> 1122<p>
1120If you don't want to use laptop-mode, it's still possible to minimize disk 1123If you don't want to use laptop-mode, it's still possible to minimize disk
1121access by mounting certain directories as <e>tmpfs</e> - write accesses are not 1124access by mounting certain directories as <c>tmpfs</c> - write accesses are not
1122stored on a disk, but in main memory and get lost with unmounting. Often it's 1125stored on a disk, but in main memory and get lost with unmounting. Often it's
1123useful to mount <path>/tmp</path> like this - you don't have to pay special 1126useful to mount <path>/tmp</path> like this - you don't have to pay special
1124attention as it gets cleared on every reboot regardless whether it was mounted 1127attention as it gets cleared on every reboot regardless whether it was mounted
1125on disk or in RAM. Just make sure you have enough RAM and no program (like a 1128on disk or in RAM. Just make sure you have enough RAM and no program (like a
1126download client or compress utility) needs extraordinary much space in 1129download client or compress utility) needs extraordinary much space in
1132none /tmp tmpfs size=32m 0 0 1135none /tmp tmpfs size=32m 0 0
1133</pre> 1136</pre>
1134 1137
1135<warn> 1138<warn>
1136Pay attention to the size parameter and modify it for your system. If you're 1139Pay attention to the size parameter and modify it for your system. If you're
1137unsure, don't try this at all, it can become a perfomance bottleneck easily. In 1140unsure, don't try this at all, it can become a performance bottleneck easily. In
1138case you want to mount <path>/var/log</path> like this, make sure to merge the 1141case you want to mount <path>/var/log</path> like this, make sure to merge the
1139log files to disk before unmounting. They are essential. Don't attempt to mount 1142log files to disk before unmounting. They are essential. Don't attempt to mount
1140/var/tmp like this. Portage uses it for compiling... 1143<path>/var/tmp</path> like this. Portage uses it for compiling...
1141</warn> 1144</warn>
1142 1145
1143</body> 1146</body>
1144</section> 1147</section>
1145</chapter> 1148</chapter>
1146 1149
1147<chapter> 1150<chapter>
1148<title>Power Management for other devices</title> 1151<title>Power Management For Other Devices</title>
1149<section> 1152<section>
1150<title>Graphics cards</title> 1153<title>Graphics Cards</title>
1151<body> 1154<body>
1152 1155
1153<p> 1156<p>
1154In case you own an ATI graphics card supporting PowerPlay (dynamic clock 1157In case you own an ATI graphics card supporting PowerPlay (dynamic clock
1155scaling for the the graphics processing unit GPU), you can activate this 1158scaling for the the graphics processing unit GPU), you can activate this
1156feature in X.org. Open <path>/etc/X11/xorg.conf</path> and add (or enable) 1159feature in X.org. Open <path>/etc/X11/xorg.conf</path> and add (or enable) the
1157the <c>DynamicClocks</c> option in the Device section. Please notice that 1160<c>DynamicClocks</c> option in the Device section. Please notice that this
1158this feature will lead to crashes on some systems. 1161feature will lead to crashes on some systems.
1159</p> 1162</p>
1160 1163
1161<pre caption="Enabling ATI PowerPlay support in X.org"> 1164<pre caption="Enabling ATI PowerPlay support in X.org">
1162Section "Device" 1165Section "Device"
1163[...] 1166[...]
1171<title>Wireless Power Management</title> 1174<title>Wireless Power Management</title>
1172<body> 1175<body>
1173 1176
1174<p> 1177<p>
1175Wireless LAN cards consume quite a bit of energy. Put them in Power Management 1178Wireless LAN cards consume quite a bit of energy. Put them in Power Management
1176mode in analogy to the pmg_hda script. 1179mode in analogy to the <c>pmg_hda</c> script.
1177</p> 1180</p>
1178 1181
1179<note> 1182<note>
1180This script assumes your wireless interface is called <c>wlan0</c>; replace 1183This script assumes your wireless interface is called <c>wlan0</c>; replace
1181this with the actual name of your interface. 1184this with the actual name of your interface.
1221There are two problems with USB devices regarding energy consumption: First, 1224There are two problems with USB devices regarding energy consumption: First,
1222devices like USB mice, digital cameras or USB sticks consume energy while 1225devices like USB mice, digital cameras or USB sticks consume energy while
1223plugged in. You cannot avoid this (nevertheless remove them in case they're not 1226plugged in. You cannot avoid this (nevertheless remove them in case they're not
1224needed). Second, when there are USB devices plugged in, the USB host controller 1227needed). Second, when there are USB devices plugged in, the USB host controller
1225periodically accesses the bus which in turn prevents the CPU from going into 1228periodically accesses the bus which in turn prevents the CPU from going into
1226sleep mode. The kernel offers an experimental option to enable suspension of 1229sleep mode. The kernel offers an experimental option to enable suspension of
1227USB devices through driver calls or one of the <path>power/state</path> files 1230USB devices through driver calls or one of the <path>power/state</path> files
1228in <path>/sys</path>. 1231in <path>/sys</path>.
1229</p> 1232</p>
1230 1233
1231<pre caption="Enabling USB suspend support in the kernel"> 1234<pre caption="Enabling USB suspend support in the kernel">
1238</body> 1241</body>
1239</section> 1242</section>
1240</chapter> 1243</chapter>
1241 1244
1242<chapter> 1245<chapter>
1243<title>Sleep states: sleep, standby, suspend to disk</title> 1246<title>Sleep States: sleep, standby, and suspend to disk</title>
1244<section> 1247<section>
1245<body> 1248<body>
1246 1249
1247<p> 1250<p>
1248ACPI defines different sleep states. The more important ones are 1251ACPI defines different sleep states. The more important ones are
1249</p> 1252</p>
1250 1253
1251<ul> 1254<ul>
1252 <li>S1 aka Standby</li> 1255 <li>S1 aka Standby</li>
1253 <li>S3 aka Suspend to RAM aka Sleep</li> 1256 <li>S3 aka Suspend to RAM aka Sleep</li>
1254 <li>S4 aka Suspend to Disk aka Hibernate</li> 1257 <li>S4 aka Suspend to Disk aka Hibernate</li>
1255</ul> 1258</ul>
1256 1259
1284<c>hibernate-script</c> to activate suspend or sleep mode. Let's install that 1287<c>hibernate-script</c> to activate suspend or sleep mode. Let's install that
1285first. 1288first.
1286</p> 1289</p>
1287 1290
1288<pre caption="Installing the hibernate-script"> 1291<pre caption="Installing the hibernate-script">
1289<i># emerge hibernate-script</i> 1292# <i>emerge hibernate-script</i>
1290</pre> 1293</pre>
1291 1294
1292<p> 1295<p>
1293Some configuration has to be done in <path>/etc/hibernate</path> The default 1296Some configuration has to be done in <path>/etc/hibernate</path> The default
1294package introduces two configuration files <path>hibernate.conf</path> and 1297package introduces two configuration files <path>hibernate.conf</path> and
1305</p> 1308</p>
1306 1309
1307<p> 1310<p>
1308Ready? Now is the last chance to backup any data you want to keep after 1311Ready? Now is the last chance to backup any data you want to keep after
1309executing the next command. Notice that you probably have to hit a special key 1312executing the next command. Notice that you probably have to hit a special key
1310like <e>Fn</e> to resume from sleep. 1313like <c>Fn</c> to resume from sleep.
1311</p> 1314</p>
1312 1315
1313<pre caption="Calling sleep"> 1316<pre caption="Calling sleep">
1314<i># hibernate-ram</i> 1317# <i>hibernate-ram</i>
1315</pre> 1318</pre>
1316 1319
1317<p> 1320<p>
1318If you're still reading, it seems to work. You can also setup standby (S1) in 1321If you're still reading, it seems to work. You can also setup standby (S1) in a
1319a similar way by copying <path>ram.conf</path> to <path>standby.conf</path> 1322similar way by copying <path>ram.conf</path> to <path>standby.conf</path> and
1320and creating a symlink <path>/usr/sbin/hibernate-standby</path> pointing to 1323creating a symlink <path>/usr/sbin/hibernate-standby</path> pointing to
1321<path>/usr/sbin/hibernate</path>. S3 and S4 are the more interesting sleep 1324<path>/usr/sbin/hibernate</path>. S3 and S4 are the more interesting sleep
1322states due to greater energy savings however. 1325states due to greater energy savings however.
1323</p> 1326</p>
1324 1327
1325</body> 1328</body>
1340Shutdown any NFS or samba server/client before hibernating. 1343Shutdown any NFS or samba server/client before hibernating.
1341</warn> 1344</warn>
1342 1345
1343<p> 1346<p>
1344There are two different implementations for S4. The original one is swsusp, 1347There are two different implementations for S4. The original one is swsusp,
1345then there is the newer suspend2 with a nicer interface (including 1348then there is the newer suspend2 with a nicer interface (including fbsplash
1346fbsplash support). A <uri link="http://suspend2.net/features.html#compare"> 1349support). A <uri link="http://suspend2.net/features.html#compare"> feature
1347feature comparison</uri> is available at the <uri link="http://suspend2.net"> 1350comparison</uri> is available at the <uri link="http://suspend2.net"> suspend2
1348suspend2 Homepage</uri>. There used to be Suspend-to-Disk (pmdisk), a fork of 1351Homepage</uri>. There used to be Suspend-to-Disk (pmdisk), a fork of swsusp,
1349swsusp, but it has been merged back. 1352but it has been merged back.
1350</p> 1353</p>
1351 1354
1352<p> 1355<p>
1353Suspend2 is not included in the mainline kernel yet, therefore you either have 1356Suspend2 is not included in the mainline kernel yet, therefore you either have
1354to patch your kernel sources with the patches provided by 1357to patch your kernel sources with the patches provided by <uri
1355<uri link="http://suspend2.net">suspend2.net</uri> or use 1358link="http://suspend2.net">suspend2.net</uri> or use
1356<c>sys-kernel/suspend2-sources</c>. 1359<c>sys-kernel/suspend2-sources</c>.
1357</p> 1360</p>
1358 1361
1359<p> 1362<p>
1360The kernel part for both swusp and suspend2 is as follows: 1363The kernel part for both swusp and suspend2 is as follows:
1364Power Management Options ---&gt; 1367Power Management Options ---&gt;
1365 <comment>(hibernate with swsusp)</comment> 1368 <comment>(hibernate with swsusp)</comment>
1366 [*] Software Suspend 1369 [*] Software Suspend
1367 <comment>(replace /dev/SWAP with your swap partition)</comment> 1370 <comment>(replace /dev/SWAP with your swap partition)</comment>
1368 (/dev/SWAP) Default resume partition 1371 (/dev/SWAP) Default resume partition
1369 1372
1370 <comment>(hibernate with suspend2)</comment> 1373 <comment>(hibernate with suspend2)</comment>
1371 Software Suspend 2 1374 Software Suspend 2
1372 --- Image Storage (you need at least one writer) 1375 --- Image Storage (you need at least one writer)
1373 [*] File Writer 1376 [*] File Writer
1374 [*] Swap Writer 1377 [*] Swap Writer
1382<p> 1385<p>
1383The configuration for swsusp is rather easy. If you didn't store the location 1386The configuration for swsusp is rather easy. If you didn't store the location
1384of your swap partition in the kernel config, you can also pass it as a 1387of your swap partition in the kernel config, you can also pass it as a
1385parameter with the <c>resume=/dev/SWAP</c> directive. If booting is not 1388parameter with the <c>resume=/dev/SWAP</c> directive. If booting is not
1386possible due to a broken image, use the <c>noresume</c> kernel parameter. The 1389possible due to a broken image, use the <c>noresume</c> kernel parameter. The
1387<c>hibernate-cleanup</c> init script invalidates swsusp images during the 1390<c>hibernate-cleanup</c> init script invalidates swsusp images during the boot
1388boot process. 1391process.
1389</p> 1392</p>
1390 1393
1391<pre caption="Invalidating swsusp images during the boot process"> 1394<pre caption="Invalidating swsusp images during the boot process">
1392<i># rc-update add hibernate-cleanup boot</i> 1395# <i>rc-update add hibernate-cleanup boot</i>
1393</pre> 1396</pre>
1394 1397
1395<p> 1398<p>
1396To activate hibernate with swsusp, use the hibernate script and set 1399To activate hibernate with swsusp, use the hibernate script and set
1397<c>UseSysfsPowerState disk</c> in <path>/etc/hibernate/hibernate.conf</path>. 1400<c>UseSysfsPowerState disk</c> in <path>/etc/hibernate/hibernate.conf</path>.
1400<warn> 1403<warn>
1401Backup your data before doing this. Run <c>sync</c> before executing one of the 1404Backup your data before doing this. Run <c>sync</c> before executing one of the
1402commands to have cached data written to disk. First try it outside of X, then 1405commands to have cached data written to disk. First try it outside of X, then
1403with X running, but not logged in. 1406with X running, but not logged in.
1404</warn> 1407</warn>
1405 1408
1406<p> 1409<p>
1407If you experience kernel panics due to uhci or similar, try to compile USB 1410If you experience kernel panics due to uhci or similar, try to compile USB
1408support as module and unload the modules before sending your laptop to sleep 1411support as module and unload the modules before sending your laptop to sleep
1409mode. There are configuration options for this in <path>hibernate.conf</path> 1412mode. There are configuration options for this in <path>hibernate.conf</path>
1410</p> 1413</p>
1411 1414
1412<pre caption="Hibernating with swsusp"> 1415<pre caption="Hibernating with swsusp">
1413<i># nano -w /etc/hibernate.conf</i> 1416# <i>nano -w /etc/hibernate.conf</i>
1414<comment>(Make sure you have a backup of your data)</comment> 1417<comment>(Make sure you have a backup of your data)</comment>
1415<i># hibernate</i> 1418# <i>hibernate</i>
1416</pre> 1419</pre>
1417 1420
1418<p> 1421<p>
1419The following section discusses the setup of suspend2 including fbsplash 1422The following section discusses the setup of suspend2 including fbsplash
1420support for a nice graphical progress bar during suspend and resume. 1423support for a nice graphical progress bar during suspend and resume.
1421</p> 1424</p>
1422 1425
1423<p> 1426<p>
1424The first part of the configuration is similar to the configuration of 1427The first part of the configuration is similar to the configuration of swsusp.
1425swsusp. In case you didn't store the location of your swap partition in the 1428In case you didn't store the location of your swap partition in the kernel
1426kernel config, you have to pass it as a kernel parameter with the 1429config, you have to pass it as a kernel parameter with the
1427<c>resume2=swap:/dev/SWAP</c> directive. If booting is not possible due to a 1430<c>resume2=swap:/dev/SWAP</c> directive. If booting is not possible due to a
1428broken image, append the <c>noresume2</c> parameter. Additionally, the 1431broken image, append the <c>noresume2</c> parameter. Additionally, the
1429<c>hibernate-cleanup</c> init script invalidates suspend2 images during the 1432<c>hibernate-cleanup</c> init script invalidates suspend2 images during the
1430boot process. 1433boot process.
1431</p> 1434</p>
1432 1435
1433<pre caption="Invalidating suspend2 images during the boot process"> 1436<pre caption="Invalidating suspend2 images during the boot process">
1434<i># rc-update add hibernate-cleanup boot</i> 1437# <i>rc-update add hibernate-cleanup boot</i>
1435</pre> 1438</pre>
1436 1439
1440<p>
1437<p>Now edit <path>/etc/hibernate/hibernate.conf</path>, enable the 1441Now edit <path>/etc/hibernate/hibernate.conf</path>, enable the <c>suspend2</c>
1438<e>suspend2</e> section and comment everything in the <e>sysfs_power_state</e> 1442section and comment everything in the <c>sysfs_power_state</c> and
1439and <e>acpi_sleep</e> sections. Do not enable the fbsplash part in global 1443<c>acpi_sleep</c> sections. Do not enable the <c>fbsplash</c> part in global
1440options yet. 1444options yet.
1441</p> 1445</p>
1442 1446
1443<pre caption="Hibernating with suspend2"> 1447<pre caption="Hibernating with suspend2">
1444<i># nano -w /etc/hibernate.conf</i> 1448# <i>nano -w /etc/hibernate.conf</i>
1445<comment>(Make sure you have a backup of your data)</comment> 1449<comment>(Make sure you have a backup of your data)</comment>
1446<i># hibernate</i> 1450# <i>hibernate</i>
1447</pre> 1451</pre>
1448 1452
1449<p> 1453<p>
1450Please configure fbsplash now if you didn't do already. To enable fbsplash 1454Please configure <c>fbsplash</c> now if you didn't do already. To enable
1451support during hibernation, the <c>sys-apps/suspend2-userui</c> package is 1455fbsplash support during hibernation, the <c>sys-apps/suspend2-userui</c>
1452needed. Additionally, you've got to enable the <e>fbsplash</e> USE flag. 1456package is needed. Additionally, you've got to enable the <c>fbsplash</c> USE
1457flag.
1453</p> 1458</p>
1454 1459
1455<pre caption="Installing suspend2-userui"> 1460<pre caption="Installing suspend2-userui">
1456<i># mkdir -p /etc/portage</i> 1461# <i>mkdir -p /etc/portage</i>
1457<i># echo sys-apps/suspend2-userui fbsplash >> /etc/portage/package.use</i> 1462# <i>echo "sys-apps/suspend2-userui fbsplash" >> /etc/portage/package.use</i>
1458<i># emerge suspend2-userui</i> 1463# <i>emerge suspend2-userui</i>
1459</pre> 1464</pre>
1460 1465
1461<p> 1466<p>
1462The ebuild tells you to make a symlink to the theme you want to use. For 1467The ebuild tells you to make a symlink to the theme you want to use. For
1463example, to use the <c>livecd-2005.1</c> theme, run the following command: 1468example, to use the <c>livecd-2005.1</c> theme, run the following command:
1464</p> 1469</p>
1465 1470
1466<pre caption="Using the livecd-2005.1 theme during hibernation"> 1471<pre caption="Using the livecd-2005.1 theme during hibernation">
1467<i># ln -sfn /etc/splash/livecd-2005.1 /etc/splash/suspend2</i> 1472# <i>ln -sfn /etc/splash/livecd-2005.1 /etc/splash/suspend2</i>
1468</pre> 1473</pre>
1469 1474
1470<p> 1475<p>
1471If you don't want a black screen in the first part of the resume process, you 1476If you don't want a black screen in the first part of the resume process, you
1472have to add the <c>suspend2ui_fbsplash</c> tool to your initrd image. Assuming 1477have to add the <c>suspend2ui_fbsplash</c> tool to your initrd image. Assuming
1473you created the initrd image with <c>splash_geninitramfs</c> and saved it as 1478you created the initrd image with <c>splash_geninitramfs</c> and saved it as
1474<path>/boot/fbsplash-emergence-1024x768</path>, here's how to do 1479<path>/boot/fbsplash-emergence-1024x768</path>, here's how to do that.
1475that.
1476</p> 1480</p>
1477 1481
1478<pre caption="Adding suspend2ui_fbsplash to an initrd image"> 1482<pre caption="Adding suspend2ui_fbsplash to an initrd image">
1479<i># mount /boot</i> 1483# <i>mount /boot</i>
1480<i># mkdir ~/initrd.d</i> 1484# <i>mkdir ~/initrd.d</i>
1481<i># cp /boot/fbsplash-emergence-1024x768 ~/initrd.d/</i> 1485# <i>cp /boot/fbsplash-emergence-1024x768 ~/initrd.d/</i>
1482<i># cd ~/initrd.d</i> 1486# <i>cd ~/initrd.d</i>
1483<i># gunzip -c fbsplash-emergence-1024x768 | cpio -idm --quiet -H newc</i> 1487# <i>gunzip -c fbsplash-emergence-1024x768 | cpio -idm --quiet -H newc</i>
1484<i># rm fbsplash-emergence-1024x768</i> 1488# <i>rm fbsplash-emergence-1024x768</i>
1485<i># cp /usr/sbin/suspend2ui_fbsplash sbin/</i> 1489# <i>cp /usr/sbin/suspend2ui_fbsplash sbin/</i>
1486<i># find . | cpio --quiet --dereference -o -H newc | gzip -9 > /boot/fbsplash-suspend2-emergence-1024x768</i> 1490# <i>find . | cpio --quiet --dereference -o -H newc | gzip -9 > /boot/fbsplash-suspend2-emergence-1024x768</i>
1487</pre> 1491</pre>
1488 1492
1489<p> 1493<p>
1490Afterwards adjust <path>grub.conf</path> respectively <path>lilo.conf</path> 1494Afterwards adjust <path>grub.conf</path> respectively <path>lilo.conf</path> so
1491so that your suspend2 kernel uses 1495that your suspend2 kernel uses
1492<path>/boot/fbsplash-suspend2-emergence-1024x768</path> as initrd image. You 1496<path>/boot/fbsplash-suspend2-emergence-1024x768</path> as initrd image. You
1493can now test a dry run to see if everything is setup correctly. 1497can now test a dry run to see if everything is setup correctly.
1494</p> 1498</p>
1495 1499
1496<pre caption="Test run for fbsplash hibernation"> 1500<pre caption="Test run for fbsplash hibernation">
1497<i># suspend2ui_fbsplash -t</i> 1501# <i>suspend2ui_fbsplash -t</i>
1498</pre> 1502</pre>
1499 1503
1500<p> 1504<p>
1501Afterwards open <path>/etc/hibernate/hibernate.conf</path> again and activate 1505Afterwards open <path>/etc/hibernate/hibernate.conf</path> again and activate
1502the fbsplash options. Execute <c>hibernate</c> and enjoy. 1506the fbsplash options. Execute <c>hibernate</c> and enjoy.
1541Try to update the BIOS, especially if a broken DSDT is reported. You can also 1545Try to update the BIOS, especially if a broken DSDT is reported. You can also
1542try to fix it yourself (which is beyond the scope of this guide). 1546try to fix it yourself (which is beyond the scope of this guide).
1543</p> 1547</p>
1544 1548
1545<p> 1549<p>
1546<e>Q:</e> My laptop supports frequency scaling, but according to /proc/cpuinfo 1550<e>Q:</e> My laptop supports frequency scaling, but according to
1547the speed never changes. 1551<path>/proc/cpuinfo</path> the speed never changes.
1548</p> 1552</p>
1549 1553
1550<p> 1554<p>
1551<e>A:</e> Probably you have activated symmetric multiprocessing support 1555<e>A:</e> Probably you have activated symmetric multiprocessing support
1552(CONFIG_SMP) in your kernel. Deactivate it and it should work. Some older 1556(CONFIG_SMP) in your kernel. Deactivate it and it should work. Some older
1553kernels had a bug causing this. In that case, run <c>emerge x86info</c>, 1557kernels had a bug causing this. In that case, run <c>emerge x86info</c>, update
1554update your kernel as asked and check the current frequency with 1558your kernel as asked and check the current frequency with
1555<c>x86info -mhz</c>. 1559<c>x86info -mhz</c>.
1556</p> 1560</p>
1557 1561
1558<p> 1562<p>
1559<e>Q:</e> I can change the CPU frequency, but the range is not as wide as in 1563<e>Q:</e> I can change the CPU frequency, but the range is not as wide as in
1598<e>A:</e> Check that battery support is compiled into your kernel. If you use 1602<e>A:</e> Check that battery support is compiled into your kernel. If you use
1599it as a module, make sure the module is loaded. 1603it as a module, make sure the module is loaded.
1600</p> 1604</p>
1601 1605
1602<p> 1606<p>
1603<e>Q:</e> My system logger reports things like "logger: ACPI group battery / action 1607<e>Q:</e> My system logger reports things like "logger: ACPI group battery /
1604battery is not defined". 1608action battery is not defined".
1605</p>
1606
1607<p> 1609</p>
1610
1611<p>
1608<e>A:</e> This message is generated by the /etc/acpi/default.sh script that is 1612<e>A:</e> This message is generated by the <path>/etc/acpi/default.sh</path>
1609shipped with acpid. You can safely ignore it. If you like to get rid of it, you 1613script that is shipped with acpid. You can safely ignore it. If you like to get
1610can comment the appropriate line in /etc/acpi/default.sh as shown below: 1614rid of it, you can comment the appropriate line in
1615<path>/etc/acpi/default.sh</path> as shown below:
1611</p> 1616</p>
1612 1617
1613<pre caption="Disabling warnings about unknown acpi events"> 1618<pre caption="Disabling warnings about unknown acpi events">
1614 *) # logger "ACPI action $action is not defined" 1619 *) # logger "ACPI action $action is not defined"
1615</pre> 1620</pre>
1622<e>A:</e> This seems to be a kernel bug. Read on <uri 1627<e>A:</e> This seems to be a kernel bug. Read on <uri
1623link="http://bugme.osdl.org/show_bug.cgi?id=1752">here</uri>. 1628link="http://bugme.osdl.org/show_bug.cgi?id=1752">here</uri>.
1624</p> 1629</p>
1625 1630
1626<p> 1631<p>
1627<e>Q:</e> I activated the DynamicClocks option in <path>xorg.conf</path> and 1632<e>Q:</e> I activated the <c>DynamicClocks</c> option in <path>xorg.conf</path>
1628now X.org crashes / the screen stays black / my laptop doesn't shutdown 1633and now X.org crashes / the screen stays black / my laptop doesn't shutdown
1629properly. 1634properly.
1630</p> 1635</p>
1631 1636
1632<p> 1637<p>
1633<e>A:</e> This happens on some systems. You have to disable DynamicClocks. 1638<e>A:</e> This happens on some systems. You have to disable
1639<c>DynamicClocks</c>.
1634</p> 1640</p>
1635 1641
1636<p> 1642<p>
1637<e>Q:</e> I want to use suspend2, but it tells me my swap partition is too 1643<e>Q:</e> I want to use suspend2, but it tells me my swap partition is too
1638small. Resizing is not an option. 1644small. Resizing is not an option.
1639</p> 1645</p>
1640 1646
1641<p> 1647<p>
1642<e>A:</e> If there is enough free space on your system, you can use the 1648<e>A:</e> If there is enough free space on your system, you can use the
1643filewriter instead of the swapwriter. The <c>hibernate-script</c> supports it 1649filewriter instead of the swapwriter. The <c>hibernate-script</c> supports it
1644as well. More information can be found in 1650as well. More information can be found in
1645<path>/usr/src/linux/Documentation/power/suspend2.txt</path>. 1651<path>/usr/src/linux/Documentation/power/suspend2.txt</path>.
1646</p> 1652</p>
1647 1653
1650minutes! What am I doing wrong? 1656minutes! What am I doing wrong?
1651</p> 1657</p>
1652 1658
1653<p> 1659<p>
1654<e>A:</e> First follow your manufacturer's advice on how to charge the battery 1660<e>A:</e> First follow your manufacturer's advice on how to charge the battery
1655correctly. 1661correctly.
1656</p> 1662</p>
1657 1663
1658<p> 1664<p>
1659<e>Q:</e> The above didn't help. What should I do then? 1665<e>Q:</e> The above didn't help. What should I do then?
1660</p> 1666</p>
1678<e>Q:</e> My problem is not listed above. Where should I go next? 1684<e>Q:</e> My problem is not listed above. Where should I go next?
1679</p> 1685</p>
1680 1686
1681<p> 1687<p>
1682<e>A:</e> Don't fear to contact me, <mail link="earthwings@gentoo.org">Dennis 1688<e>A:</e> Don't fear to contact me, <mail link="earthwings@gentoo.org">Dennis
1683Nienhüser</mail>, directly. The 1689Nienhüser</mail>, directly. The <uri link="http://forums.gentoo.org">Gentoo
1684<uri link="http://forums.gentoo.org">Gentoo Forums</uri> are a good place to 1690Forums</uri> are a good place to get help as well. If you prefer IRC, try the
1685get help as well. If you prefer IRC, try the <e>#gentoo-laptop</e> channel at 1691<c>#gentoo-laptop</c> channel at <uri
1686<e>irc.freenode.net</e>. 1692link="irc://irc.freenode.net">irc.freenode.net</uri>.
1687</p> 1693</p>
1688 1694
1689</body> 1695</body>
1690</section> 1696</section>
1691</chapter> 1697</chapter>

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