1How to conserve battery power using laptop-mode
2-----------------------------------------------
3
4Document Author: Bart Samwel (bart@samwel.tk)
5Date created: January 2, 2004
6Last modified: December 06, 2004
7
8Introduction
9------------
10
11Laptop mode is used to minimize the time that the hard disk needs to be spun up,
12to conserve battery power on laptops. It has been reported to cause significant
13power savings.
14
15Contents
16--------
17
18* Introduction
19* Installation
20* Caveats
21* The Details
22* Tips & Tricks
23* Control script
24* ACPI integration
25* Monitoring tool
26
27
28Installation
29------------
30
31To use laptop mode, you don't need to set any kernel configuration options
32or anything. Simply install all the files included in this document, and
33laptop mode will automatically be started when you're on battery. For
34your convenience, a tarball containing an installer can be downloaded at:
35
36http://www.samwel.tk/laptop_mode/laptop_mode/
37
38To configure laptop mode, you need to edit the configuration file, which is
39located in /etc/default/laptop-mode on Debian-based systems, or in
40/etc/sysconfig/laptop-mode on other systems.
41
42Unfortunately, automatic enabling of laptop mode does not work for
43laptops that don't have ACPI. On those laptops, you need to start laptop
44mode manually. To start laptop mode, run "laptop_mode start", and to
45stop it, run "laptop_mode stop". (Note: The laptop mode tools package now
46has experimental support for APM, you might want to try that first.)
47
48
49Caveats
50-------
51
52* The downside of laptop mode is that you have a chance of losing up to 10
53  minutes of work. If you cannot afford this, don't use it! The supplied ACPI
54  scripts automatically turn off laptop mode when the battery almost runs out,
55  so that you won't lose any data at the end of your battery life.
56
57* Most desktop hard drives have a very limited lifetime measured in spindown
58  cycles, typically about 50.000 times (it's usually listed on the spec sheet).
59  Check your drive's rating, and don't wear down your drive's lifetime if you
60  don't need to.
61
62* If you mount some of your ext3/reiserfs filesystems with the -n option, then
63  the control script will not be able to remount them correctly. You must set
64  DO_REMOUNTS=0 in the control script, otherwise it will remount them with the
65  wrong options -- or it will fail because it cannot write to /etc/mtab.
66
67* If you have your filesystems listed as type "auto" in fstab, like I did, then
68  the control script will not recognize them as filesystems that need remounting.
69  You must list the filesystems with their true type instead.
70
71* It has been reported that some versions of the mutt mail client use file access
72  times to determine whether a folder contains new mail. If you use mutt and
73  experience this, you must disable the noatime remounting by setting the option
74  DO_REMOUNT_NOATIME to 0 in the configuration file.
75
76
77The Details
78-----------
79
80Laptop mode is controlled by the knob /proc/sys/vm/laptop_mode. This knob is
81present for all kernels that have the laptop mode patch, regardless of any
82configuration options. When the knob is set, any physical disk I/O (that might
83have caused the hard disk to spin up) causes Linux to flush all dirty blocks. The
84result of this is that after a disk has spun down, it will not be spun up
85anymore to write dirty blocks, because those blocks had already been written
86immediately after the most recent read operation. The value of the laptop_mode
87knob determines the time between the occurrence of disk I/O and when the flush
88is triggered. A sensible value for the knob is 5 seconds. Setting the knob to
890 disables laptop mode.
90
91To increase the effectiveness of the laptop_mode strategy, the laptop_mode
92control script increases dirty_expire_centisecs and dirty_writeback_centisecs in
93/proc/sys/vm to about 10 minutes (by default), which means that pages that are
94dirtied are not forced to be written to disk as often. The control script also
95changes the dirty background ratio, so that background writeback of dirty pages
96is not done anymore. Combined with a higher commit value (also 10 minutes) for
97ext3 or ReiserFS filesystems (also done automatically by the control script),
98this results in concentration of disk activity in a small time interval which
99occurs only once every 10 minutes, or whenever the disk is forced to spin up by
100a cache miss. The disk can then be spun down in the periods of inactivity.
101
102If you want to find out which process caused the disk to spin up, you can
103gather information by setting the flag /proc/sys/vm/block_dump. When this flag
104is set, Linux reports all disk read and write operations that take place, and
105all block dirtyings done to files. This makes it possible to debug why a disk
106needs to spin up, and to increase battery life even more. The output of
107block_dump is written to the kernel output, and it can be retrieved using
108"dmesg". When you use block_dump and your kernel logging level also includes
109kernel debugging messages, you probably want to turn off klogd, otherwise
110the output of block_dump will be logged, causing disk activity that is not
111normally there.
112
113
114Configuration
115-------------
116
117The laptop mode configuration file is located in /etc/default/laptop-mode on
118Debian-based systems, or in /etc/sysconfig/laptop-mode on other systems. It
119contains the following options:
120
121MAX_AGE:
122
123Maximum time, in seconds, of hard drive spindown time that you are
124comfortable with. Worst case, it's possible that you could lose this
125amount of work if your battery fails while you're in laptop mode.
126
127MINIMUM_BATTERY_MINUTES:
128
129Automatically disable laptop mode if the remaining number of minutes of
130battery power is less than this value. Default is 10 minutes.
131
132AC_HD/BATT_HD:
133
134The idle timeout that should be set on your hard drive when laptop mode
135is active (BATT_HD) and when it is not active (AC_HD). The defaults are
13620 seconds (value 4) for BATT_HD  and 2 hours (value 244) for AC_HD. The
137possible values are those listed in the manual page for "hdparm" for the
138"-S" option.
139
140HD:
141
142The devices for which the spindown timeout should be adjusted by laptop mode.
143Default is /dev/hda. If you specify multiple devices, separate them by a space.
144
145READAHEAD:
146
147Disk readahead, in 512-byte sectors, while laptop mode is active. A large
148readahead can prevent disk accesses for things like executable pages (which are
149loaded on demand while the application executes) and sequentially accessed data
150(MP3s).
151
152DO_REMOUNTS:
153
154The control script automatically remounts any mounted journaled filesystems
155with appropriate commit interval options. When this option is set to 0, this
156feature is disabled.
157
158DO_REMOUNT_NOATIME:
159
160When remounting, should the filesystems be remounted with the noatime option?
161Normally, this is set to "1" (enabled), but there may be programs that require
162access time recording.
163
164DIRTY_RATIO:
165
166The percentage of memory that is allowed to contain "dirty" or unsaved data
167before a writeback is forced, while laptop mode is active. Corresponds to
168the /proc/sys/vm/dirty_ratio sysctl.
169
170DIRTY_BACKGROUND_RATIO:
171
172The percentage of memory that is allowed to contain "dirty" or unsaved data
173after a forced writeback is done due to an exceeding of DIRTY_RATIO. Set
174this nice and low. This corresponds to the /proc/sys/vm/dirty_background_ratio
175sysctl.
176
177Note that the behaviour of dirty_background_ratio is quite different
178when laptop mode is active and when it isn't. When laptop mode is inactive,
179dirty_background_ratio is the threshold percentage at which background writeouts
180start taking place. When laptop mode is active, however, background writeouts
181are disabled, and the dirty_background_ratio only determines how much writeback
182is done when dirty_ratio is reached.
183
184DO_CPU:
185
186Enable CPU frequency scaling when in laptop mode. (Requires CPUFreq to be setup.
187See Documentation/cpu-freq/user-guide.txt for more info. Disabled by default.)
188
189CPU_MAXFREQ:
190
191When on battery, what is the maximum CPU speed that the system should use? Legal
192values are "slowest" for the slowest speed that your CPU is able to operate at,
193or a value listed in /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies.
194
195
196Tips & Tricks
197-------------
198
199* Bartek Kania reports getting up to 50 minutes of extra battery life (on top
200  of his regular 3 to 3.5 hours) using a spindown time of 5 seconds (BATT_HD=1).
201
202* You can spin down the disk while playing MP3, by setting disk readahead
203  to 8MB (READAHEAD=16384). Effectively, the disk will read a complete MP3 at
204  once, and will then spin down while the MP3 is playing. (Thanks to Bartek
205  Kania.)
206
207* Drew Scott Daniels observed: "I don't know why, but when I decrease the number
208  of colours that my display uses it consumes less battery power. I've seen
209  this on powerbooks too. I hope that this is a piece of information that
210  might be useful to the Laptop Mode patch or its users."
211
212* In syslog.conf, you can prefix entries with a dash ``-'' to omit syncing the
213  file after every logging. When you're using laptop-mode and your disk doesn't
214  spin down, this is a likely culprit.
215
216* Richard Atterer observed that laptop mode does not work well with noflushd
217  (http://noflushd.sourceforge.net/), it seems that noflushd prevents laptop-mode
218  from doing its thing.
219
220* If you're worried about your data, you might want to consider using a USB
221  memory stick or something like that as a "working area". (Be aware though
222  that flash memory can only handle a limited number of writes, and overuse
223  may wear out your memory stick pretty quickly. Do _not_ use journalling
224  filesystems on flash memory sticks.)
225
226
227Configuration file for control and ACPI battery scripts
228-------------------------------------------------------
229
230This allows the tunables to be changed for the scripts via an external
231configuration file
232
233It should be installed as /etc/default/laptop-mode on Debian, and as
234/etc/sysconfig/laptop-mode on Red Hat, SUSE, Mandrake, and other work-alikes.
235
236--------------------CONFIG FILE BEGIN-------------------------------------------
237# Maximum time, in seconds, of hard drive spindown time that you are
238# comfortable with. Worst case, it's possible that you could lose this
239# amount of work if your battery fails you while in laptop mode.
240#MAX_AGE=600
241
242# Automatically disable laptop mode when the number of minutes of battery
243# that you have left goes below this threshold.
244MINIMUM_BATTERY_MINUTES=10
245
246# Read-ahead, in 512-byte sectors. You can spin down the disk while playing MP3/OGG
247# by setting the disk readahead to 8MB (READAHEAD=16384). Effectively, the disk
248# will read a complete MP3 at once, and will then spin down while the MP3/OGG is
249# playing.
250#READAHEAD=4096
251
252# Shall we remount journaled fs. with appropriate commit interval? (1=yes)
253#DO_REMOUNTS=1
254
255# And shall we add the "noatime" option to that as well? (1=yes)
256#DO_REMOUNT_NOATIME=1
257
258# Dirty synchronous ratio.  At this percentage of dirty pages the process
259# which
260# calls write() does its own writeback
261#DIRTY_RATIO=40
262
263#
264# Allowed dirty background ratio, in percent.  Once DIRTY_RATIO has been
265# exceeded, the kernel will wake flusher threads which will then reduce the
266# amount of dirty memory to dirty_background_ratio.  Set this nice and low,
267# so once some writeout has commenced, we do a lot of it.
268#
269#DIRTY_BACKGROUND_RATIO=5
270
271# kernel default dirty buffer age
272#DEF_AGE=30
273#DEF_UPDATE=5
274#DEF_DIRTY_BACKGROUND_RATIO=10
275#DEF_DIRTY_RATIO=40
276#DEF_XFS_AGE_BUFFER=15
277#DEF_XFS_SYNC_INTERVAL=30
278#DEF_XFS_BUFD_INTERVAL=1
279
280# This must be adjusted manually to the value of HZ in the running kernel
281# on 2.4, until the XFS people change their 2.4 external interfaces to work in
282# centisecs. This can be automated, but it's a work in progress that still
283# needs# some fixes. On 2.6 kernels, XFS uses USER_HZ instead of HZ for
284# external interfaces, and that is currently always set to 100. So you don't
285# need to change this on 2.6.
286#XFS_HZ=100
287
288# Should the maximum CPU frequency be adjusted down while on battery?
289# Requires CPUFreq to be setup.
290# See Documentation/cpu-freq/user-guide.txt for more info
291#DO_CPU=0
292
293# When on battery what is the maximum CPU speed that the system should
294# use? Legal values are "slowest" for the slowest speed that your
295# CPU is able to operate at, or a value listed in:
296# /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
297# Only applicable if DO_CPU=1.
298#CPU_MAXFREQ=slowest
299
300# Idle timeout for your hard drive (man hdparm for valid values, -S option)
301# Default is 2 hours on AC (AC_HD=244) and 20 seconds for battery (BATT_HD=4).
302#AC_HD=244
303#BATT_HD=4
304
305# The drives for which to adjust the idle timeout. Separate them by a space,
306# e.g. HD="/dev/hda /dev/hdb".
307#HD="/dev/hda"
308
309# Set the spindown timeout on a hard drive?
310#DO_HD=1
311
312--------------------CONFIG FILE END---------------------------------------------
313
314
315Control script
316--------------
317
318Please note that this control script works for the Linux 2.4 and 2.6 series (thanks
319to Kiko Piris).
320
321--------------------CONTROL SCRIPT BEGIN----------------------------------------
322#!/bin/bash
323
324# start or stop laptop_mode, best run by a power management daemon when
325# ac gets connected/disconnected from a laptop
326#
327# install as /sbin/laptop_mode
328#
329# Contributors to this script:   Kiko Piris
330#				 Bart Samwel
331#				 Micha Feigin
332#				 Andrew Morton
333#				 Herve Eychenne
334#				 Dax Kelson
335#
336# Original Linux 2.4 version by: Jens Axboe
337
338#############################################################################
339
340# Source config
341if [ -f /etc/default/laptop-mode ] ; then
342	# Debian
343	. /etc/default/laptop-mode
344elif [ -f /etc/sysconfig/laptop-mode ] ; then
345	# Others
346        . /etc/sysconfig/laptop-mode
347fi
348
349# Don't raise an error if the config file is incomplete
350# set defaults instead:
351
352# Maximum time, in seconds, of hard drive spindown time that you are
353# comfortable with. Worst case, it's possible that you could lose this
354# amount of work if your battery fails you while in laptop mode.
355MAX_AGE=${MAX_AGE:-'600'}
356
357# Read-ahead, in kilobytes
358READAHEAD=${READAHEAD:-'4096'}
359
360# Shall we remount journaled fs. with appropriate commit interval? (1=yes)
361DO_REMOUNTS=${DO_REMOUNTS:-'1'}
362
363# And shall we add the "noatime" option to that as well? (1=yes)
364DO_REMOUNT_NOATIME=${DO_REMOUNT_NOATIME:-'1'}
365
366# Shall we adjust the idle timeout on a hard drive?
367DO_HD=${DO_HD:-'1'}
368
369# Adjust idle timeout on which hard drive?
370HD="${HD:-'/dev/hda'}"
371
372# spindown time for HD (hdparm -S values)
373AC_HD=${AC_HD:-'244'}
374BATT_HD=${BATT_HD:-'4'}
375
376# Dirty synchronous ratio.  At this percentage of dirty pages the process which
377# calls write() does its own writeback
378DIRTY_RATIO=${DIRTY_RATIO:-'40'}
379
380# cpu frequency scaling
381# See Documentation/cpu-freq/user-guide.txt for more info
382DO_CPU=${CPU_MANAGE:-'0'}
383CPU_MAXFREQ=${CPU_MAXFREQ:-'slowest'}
384
385#
386# Allowed dirty background ratio, in percent.  Once DIRTY_RATIO has been
387# exceeded, the kernel will wake flusher threads which will then reduce the
388# amount of dirty memory to dirty_background_ratio.  Set this nice and low,
389# so once some writeout has commenced, we do a lot of it.
390#
391DIRTY_BACKGROUND_RATIO=${DIRTY_BACKGROUND_RATIO:-'5'}
392
393# kernel default dirty buffer age
394DEF_AGE=${DEF_AGE:-'30'}
395DEF_UPDATE=${DEF_UPDATE:-'5'}
396DEF_DIRTY_BACKGROUND_RATIO=${DEF_DIRTY_BACKGROUND_RATIO:-'10'}
397DEF_DIRTY_RATIO=${DEF_DIRTY_RATIO:-'40'}
398DEF_XFS_AGE_BUFFER=${DEF_XFS_AGE_BUFFER:-'15'}
399DEF_XFS_SYNC_INTERVAL=${DEF_XFS_SYNC_INTERVAL:-'30'}
400DEF_XFS_BUFD_INTERVAL=${DEF_XFS_BUFD_INTERVAL:-'1'}
401
402# This must be adjusted manually to the value of HZ in the running kernel
403# on 2.4, until the XFS people change their 2.4 external interfaces to work in
404# centisecs. This can be automated, but it's a work in progress that still needs
405# some fixes. On 2.6 kernels, XFS uses USER_HZ instead of HZ for external
406# interfaces, and that is currently always set to 100. So you don't need to
407# change this on 2.6.
408XFS_HZ=${XFS_HZ:-'100'}
409
410#############################################################################
411
412KLEVEL="$(uname -r |
413             {
414	       IFS='.' read a b c
415	       echo $a.$b
416	     }
417)"
418case "$KLEVEL" in
419	"2.4"|"2.6")
420		;;
421	*)
422		echo "Unhandled kernel version: $KLEVEL ('uname -r' = '$(uname -r)')" >&2
423		exit 1
424		;;
425esac
426
427if [ ! -e /proc/sys/vm/laptop_mode ] ; then
428	echo "Kernel is not patched with laptop_mode patch." >&2
429	exit 1
430fi
431
432if [ ! -w /proc/sys/vm/laptop_mode ] ; then
433	echo "You do not have enough privileges to enable laptop_mode." >&2
434	exit 1
435fi
436
437# Remove an option (the first parameter) of the form option=<number> from
438# a mount options string (the rest of the parameters).
439parse_mount_opts () {
440	OPT="$1"
441	shift
442	echo ",$*," | sed		\
443	 -e 's/,'"$OPT"'=[0-9]*,/,/g'	\
444	 -e 's/,,*/,/g'			\
445	 -e 's/^,//'			\
446	 -e 's/,$//'
447}
448
449# Remove an option (the first parameter) without any arguments from
450# a mount option string (the rest of the parameters).
451parse_nonumber_mount_opts () {
452	OPT="$1"
453	shift
454	echo ",$*," | sed		\
455	 -e 's/,'"$OPT"',/,/g'		\
456	 -e 's/,,*/,/g'			\
457	 -e 's/^,//'			\
458	 -e 's/,$//'
459}
460
461# Find out the state of a yes/no option (e.g. "atime"/"noatime") in
462# fstab for a given filesystem, and use this state to replace the
463# value of the option in another mount options string. The device
464# is the first argument, the option name the second, and the default
465# value the third. The remainder is the mount options string.
466#
467# Example:
468# parse_yesno_opts_wfstab /dev/hda1 atime atime defaults,noatime
469#
470# If fstab contains, say, "rw" for this filesystem, then the result
471# will be "defaults,atime".
472parse_yesno_opts_wfstab () {
473	L_DEV="$1"
474	OPT="$2"
475	DEF_OPT="$3"
476	shift 3
477	L_OPTS="$*"
478	PARSEDOPTS1="$(parse_nonumber_mount_opts $OPT $L_OPTS)"
479	PARSEDOPTS1="$(parse_nonumber_mount_opts no$OPT $PARSEDOPTS1)"
480	# Watch for a default atime in fstab
481	FSTAB_OPTS="$(awk '$1 == "'$L_DEV'" { print $4 }' /etc/fstab)"
482	if echo "$FSTAB_OPTS" | grep "$OPT" > /dev/null ; then
483		# option specified in fstab: extract the value and use it
484		if echo "$FSTAB_OPTS" | grep "no$OPT" > /dev/null ; then
485			echo "$PARSEDOPTS1,no$OPT"
486		else
487			# no$OPT not found -- so we must have $OPT.
488			echo "$PARSEDOPTS1,$OPT"
489		fi
490	else
491		# option not specified in fstab -- choose the default.
492		echo "$PARSEDOPTS1,$DEF_OPT"
493	fi
494}
495
496# Find out the state of a numbered option (e.g. "commit=NNN") in
497# fstab for a given filesystem, and use this state to replace the
498# value of the option in another mount options string. The device
499# is the first argument, and the option name the second. The
500# remainder is the mount options string in which the replacement
501# must be done.
502#
503# Example:
504# parse_mount_opts_wfstab /dev/hda1 commit defaults,commit=7
505#
506# If fstab contains, say, "commit=3,rw" for this filesystem, then the
507# result will be "rw,commit=3".
508parse_mount_opts_wfstab () {
509	L_DEV="$1"
510	OPT="$2"
511	shift 2
512	L_OPTS="$*"
513	PARSEDOPTS1="$(parse_mount_opts $OPT $L_OPTS)"
514	# Watch for a default commit in fstab
515	FSTAB_OPTS="$(awk '$1 == "'$L_DEV'" { print $4 }' /etc/fstab)"
516	if echo "$FSTAB_OPTS" | grep "$OPT=" > /dev/null ; then
517		# option specified in fstab: extract the value, and use it
518		echo -n "$PARSEDOPTS1,$OPT="
519		echo ",$FSTAB_OPTS," | sed \
520		 -e 's/.*,'"$OPT"'=//'	\
521		 -e 's/,.*//'
522	else
523		# option not specified in fstab: set it to 0
524		echo "$PARSEDOPTS1,$OPT=0"
525	fi
526}
527
528deduce_fstype () {
529	MP="$1"
530	# My root filesystem unfortunately has
531	# type "unknown" in /etc/mtab. If we encounter
532	# "unknown", we try to get the type from fstab.
533	cat /etc/fstab |
534	grep -v '^#' |
535	while read FSTAB_DEV FSTAB_MP FSTAB_FST FSTAB_OPTS FSTAB_DUMP FSTAB_DUMP ; do
536		if [ "$FSTAB_MP" = "$MP" ]; then
537			echo $FSTAB_FST
538			exit 0
539		fi
540	done
541}
542
543if [ $DO_REMOUNT_NOATIME -eq 1 ] ; then
544	NOATIME_OPT=",noatime"
545fi
546
547case "$1" in
548	start)
549		AGE=$((100*$MAX_AGE))
550		XFS_AGE=$(($XFS_HZ*$MAX_AGE))
551		echo -n "Starting laptop_mode"
552
553		if [ -d /proc/sys/vm/pagebuf ] ; then
554			# (For 2.4 and early 2.6.)
555			# This only needs to be set, not reset -- it is only used when
556			# laptop mode is enabled.
557			echo $XFS_AGE > /proc/sys/vm/pagebuf/lm_flush_age
558			echo $XFS_AGE > /proc/sys/fs/xfs/lm_sync_interval
559		elif [ -f /proc/sys/fs/xfs/lm_age_buffer ] ; then
560			# (A couple of early 2.6 laptop mode patches had these.)
561			# The same goes for these.
562			echo $XFS_AGE > /proc/sys/fs/xfs/lm_age_buffer
563			echo $XFS_AGE > /proc/sys/fs/xfs/lm_sync_interval
564		elif [ -f /proc/sys/fs/xfs/age_buffer ] ; then
565			# (2.6.6)
566			# But not for these -- they are also used in normal
567			# operation.
568			echo $XFS_AGE > /proc/sys/fs/xfs/age_buffer
569			echo $XFS_AGE > /proc/sys/fs/xfs/sync_interval
570		elif [ -f /proc/sys/fs/xfs/age_buffer_centisecs ] ; then
571			# (2.6.7 upwards)
572			# And not for these either. These are in centisecs,
573			# not USER_HZ, so we have to use $AGE, not $XFS_AGE.
574			echo $AGE > /proc/sys/fs/xfs/age_buffer_centisecs
575			echo $AGE > /proc/sys/fs/xfs/xfssyncd_centisecs
576			echo 3000 > /proc/sys/fs/xfs/xfsbufd_centisecs
577		fi
578
579		case "$KLEVEL" in
580			"2.4")
581				echo 1					> /proc/sys/vm/laptop_mode
582				echo "30 500 0 0 $AGE $AGE 60 20 0"	> /proc/sys/vm/bdflush
583				;;
584			"2.6")
585				echo 5					> /proc/sys/vm/laptop_mode
586				echo "$AGE"				> /proc/sys/vm/dirty_writeback_centisecs
587				echo "$AGE"				> /proc/sys/vm/dirty_expire_centisecs
588				echo "$DIRTY_RATIO"			> /proc/sys/vm/dirty_ratio
589				echo "$DIRTY_BACKGROUND_RATIO"		> /proc/sys/vm/dirty_background_ratio
590				;;
591		esac
592		if [ $DO_REMOUNTS -eq 1 ]; then
593			cat /etc/mtab | while read DEV MP FST OPTS DUMP PASS ; do
594				PARSEDOPTS="$(parse_mount_opts "$OPTS")"
595				if [ "$FST" = 'unknown' ]; then
596					FST=$(deduce_fstype $MP)
597				fi
598				case "$FST" in
599					"ext3"|"reiserfs")
600						PARSEDOPTS="$(parse_mount_opts commit "$OPTS")"
601						mount $DEV -t $FST $MP -o remount,$PARSEDOPTS,commit=$MAX_AGE$NOATIME_OPT
602						;;
603					"xfs")
604						mount $DEV -t $FST $MP -o remount,$OPTS$NOATIME_OPT
605						;;
606				esac
607				if [ -b $DEV ] ; then
608					blockdev --setra $(($READAHEAD * 2)) $DEV
609				fi
610			done
611		fi
612		if [ $DO_HD -eq 1 ] ; then
613			for THISHD in $HD ; do
614				/sbin/hdparm -S $BATT_HD $THISHD > /dev/null 2>&1
615				/sbin/hdparm -B 1 $THISHD > /dev/null 2>&1
616			done
617		fi
618		if [ $DO_CPU -eq 1 -a -e /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq ]; then
619			if [ $CPU_MAXFREQ = 'slowest' ]; then
620				CPU_MAXFREQ=`cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq`
621			fi
622			echo $CPU_MAXFREQ > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
623		fi
624		echo "."
625		;;
626	stop)
627		U_AGE=$((100*$DEF_UPDATE))
628		B_AGE=$((100*$DEF_AGE))
629		echo -n "Stopping laptop_mode"
630		echo 0 > /proc/sys/vm/laptop_mode
631		if [ -f /proc/sys/fs/xfs/age_buffer -a ! -f /proc/sys/fs/xfs/lm_age_buffer ] ; then
632			# These need to be restored, if there are no lm_*.
633			echo $(($XFS_HZ*$DEF_XFS_AGE_BUFFER))	 	> /proc/sys/fs/xfs/age_buffer
634			echo $(($XFS_HZ*$DEF_XFS_SYNC_INTERVAL)) 	> /proc/sys/fs/xfs/sync_interval
635		elif [ -f /proc/sys/fs/xfs/age_buffer_centisecs ] ; then
636			# These need to be restored as well.
637			echo $((100*$DEF_XFS_AGE_BUFFER))	> /proc/sys/fs/xfs/age_buffer_centisecs
638			echo $((100*$DEF_XFS_SYNC_INTERVAL))	> /proc/sys/fs/xfs/xfssyncd_centisecs
639			echo $((100*$DEF_XFS_BUFD_INTERVAL))	> /proc/sys/fs/xfs/xfsbufd_centisecs
640		fi
641		case "$KLEVEL" in
642			"2.4")
643				echo "30 500 0 0 $U_AGE $B_AGE 60 20 0"	> /proc/sys/vm/bdflush
644				;;
645			"2.6")
646				echo "$U_AGE"				> /proc/sys/vm/dirty_writeback_centisecs
647				echo "$B_AGE"				> /proc/sys/vm/dirty_expire_centisecs
648				echo "$DEF_DIRTY_RATIO"			> /proc/sys/vm/dirty_ratio
649				echo "$DEF_DIRTY_BACKGROUND_RATIO"	> /proc/sys/vm/dirty_background_ratio
650				;;
651		esac
652		if [ $DO_REMOUNTS -eq 1 ] ; then
653			cat /etc/mtab | while read DEV MP FST OPTS DUMP PASS ; do
654				# Reset commit and atime options to defaults.
655				if [ "$FST" = 'unknown' ]; then
656					FST=$(deduce_fstype $MP)
657				fi
658				case "$FST" in
659					"ext3"|"reiserfs")
660						PARSEDOPTS="$(parse_mount_opts_wfstab $DEV commit $OPTS)"
661						PARSEDOPTS="$(parse_yesno_opts_wfstab $DEV atime atime $PARSEDOPTS)"
662						mount $DEV -t $FST $MP -o remount,$PARSEDOPTS
663						;;
664					"xfs")
665						PARSEDOPTS="$(parse_yesno_opts_wfstab $DEV atime atime $OPTS)"
666						mount $DEV -t $FST $MP -o remount,$PARSEDOPTS
667						;;
668				esac
669				if [ -b $DEV ] ; then
670					blockdev --setra 256 $DEV
671				fi
672			done
673		fi
674		if [ $DO_HD -eq 1 ] ; then
675			for THISHD in $HD ; do
676				/sbin/hdparm -S $AC_HD $THISHD > /dev/null 2>&1
677				/sbin/hdparm -B 255 $THISHD > /dev/null 2>&1
678			done
679		fi
680		if [ $DO_CPU -eq 1 -a -e /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq ]; then
681			echo `cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq` > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
682		fi
683		echo "."
684		;;
685	*)
686		echo "Usage: $0 {start|stop}" 2>&1
687		exit 1
688		;;
689
690esac
691
692exit 0
693--------------------CONTROL SCRIPT END------------------------------------------
694
695
696ACPI integration
697----------------
698
699Dax Kelson submitted this so that the ACPI acpid daemon will
700kick off the laptop_mode script and run hdparm. The part that
701automatically disables laptop mode when the battery is low was
702written by Jan Topinski.
703
704-----------------/etc/acpi/events/ac_adapter BEGIN------------------------------
705event=ac_adapter
706action=/etc/acpi/actions/ac.sh %e
707----------------/etc/acpi/events/ac_adapter END---------------------------------
708
709
710-----------------/etc/acpi/events/battery BEGIN---------------------------------
711event=battery.*
712action=/etc/acpi/actions/battery.sh %e
713----------------/etc/acpi/events/battery END------------------------------------
714
715
716----------------/etc/acpi/actions/ac.sh BEGIN-----------------------------------
717#!/bin/bash
718
719# ac on/offline event handler
720
721status=`awk '/^state: / { print $2 }' /proc/acpi/ac_adapter/$2/state`
722
723case $status in
724        "on-line")
725                /sbin/laptop_mode stop
726                exit 0
727        ;;
728        "off-line")
729                /sbin/laptop_mode start
730                exit 0
731        ;;
732esac
733---------------------------/etc/acpi/actions/ac.sh END--------------------------
734
735
736---------------------------/etc/acpi/actions/battery.sh BEGIN-------------------
737#! /bin/bash
738
739# Automatically disable laptop mode when the battery almost runs out.
740
741BATT_INFO=/proc/acpi/battery/$2/state
742
743if [[ -f /proc/sys/vm/laptop_mode ]]
744then
745   LM=`cat /proc/sys/vm/laptop_mode`
746   if [[ $LM -gt 0 ]]
747   then
748     if [[ -f $BATT_INFO ]]
749     then
750        # Source the config file only now that we know we need
751        if [ -f /etc/default/laptop-mode ] ; then
752                # Debian
753                . /etc/default/laptop-mode
754        elif [ -f /etc/sysconfig/laptop-mode ] ; then
755                # Others
756                . /etc/sysconfig/laptop-mode
757        fi
758        MINIMUM_BATTERY_MINUTES=${MINIMUM_BATTERY_MINUTES:-'10'}
759
760        ACTION="`cat $BATT_INFO | grep charging | cut -c 26-`"
761        if [[ ACTION -eq "discharging" ]]
762        then
763           PRESENT_RATE=`cat $BATT_INFO | grep "present rate:" | sed  "s/.* \([0-9][0-9]* \).*/\1/" `
764           REMAINING=`cat $BATT_INFO | grep "remaining capacity:" | sed  "s/.* \([0-9][0-9]* \).*/\1/" `
765        fi
766        if (($REMAINING * 60 / $PRESENT_RATE < $MINIMUM_BATTERY_MINUTES))
767        then
768           /sbin/laptop_mode stop
769        fi
770     else
771       logger -p daemon.warning "You are using laptop mode and your battery interface $BATT_INFO is missing. This may lead to loss of data when the battery runs out. Check kernel ACPI support and /proc/acpi/battery folder, and edit /etc/acpi/battery.sh to set BATT_INFO to the correct path."
772     fi
773   fi
774fi
775---------------------------/etc/acpi/actions/battery.sh END--------------------
776
777
778Monitoring tool
779---------------
780
781Bartek Kania submitted this, it can be used to measure how much time your disk
782spends spun up/down.  See Documentation/laptops/dslm.c
783