Fedora Users — Re: Laptop Battery Life Again

On Sun, Jul 6, 2008 at 1:23 AM, jdow <jdow@xxxxxxxxxxxxx> wrote:

From: "Paulo Cavalcanti" <promac@xxxxxxxxx>
Sent: Saturday, 2008, July 05 12:40

Hi,

I noticed that when I boot on kernel 2.6.25,
my laptop battery, according to gnome, has 3h:40 min of
charge. However, when booting on a 2.6.24 kernel,
this number goes up to 4h:20 min.

Then, I collected some interesting links, discussing this issue.

1) http://fedoraproject.org/wiki/FWN/Issue100

2) http://www.thinkwiki.org/wiki/How_to_reduce_power_consumption

3) http://kdekorte.blogspot.com/

4) http://samwel.tk/laptop_mode/faq

5) http://lwn.net/Articles/257426/

My questions are:

1) should I follow powertop advices blindly?

2) On the first link, in the topic
Reducing Power Usage Of Fedora
https://www.redhat.com/archives/fedora-devel-list/2007-August/msg00558.html

Raul Sundaram recommends using

echo 5 > /proc/sys/vm/laptop_mode

Why this is not done automatically?

3) In the third link, there is an acpi script that really works,
and can be used to change the parameters, when switching from
battery to power chord (although some options are wrong,
specially the hdparm use - be careful).

4) What about laptop-mode-tools available from Dries' repo?

5) Why different kernels have different expectations, regarding battery
discharge?

I would like to hear some advice, because I have not owned
a laptop for some time, and I do not want to burst my HD
or shorten my battery life.

Google for it on the LKML. There was a discussion there in the last week.

Thanks, I found it.

http://lkml.org/lkml/2008/7/5/99

Well, what I am doing for now is using /etc/rc.local,
/etc/acpi/actions/battery.sh, and /etc/acpi/events/battery.conf.

I commented some options because I do not have bluetooth,
my laptop does not support wake on LAN, I want my laptop_mode always ON,
and I am avoiding aggressive power savings for my disk.

Now, I just need some time to evaluate the results.....

--------------------------------------------------------------------------

#!/bin/sh
#
# This script will be executed *after* all the other init scripts.
# You can put your own initialization stuff in here if you don't
# want to do the full Sys V style init stuff.

touch /var/lock/subsys/local

# roma

echo 5 > /proc/sys/vm/laptop_mode
/sbin/hdparm -B 254 /dev/sda

-------------------------------------------------------------------------------------------

#!/bin/bash
# /etc/acpi/actions/battery.sh
state=`grep on-line /proc/acpi/ac_adapter/AC/state | wc -l`
if [ $state -gt 0 ]; then
   hal-disable-polling --device /dev/scd0 --enable-polling
   # echo 0 > /proc/sys/vm/laptop_mode
   echo 0 > /sys/devices/system/cpu/sched_mc_power_savings
   # /sbin/hdparm -B 254 -S 0 /dev/sda
   echo 499 > /proc/sys/vm/dirty_writeback_centisecs
   # for i in /sys/bus/usb/devices/*/power/autosuspend; do echo 0 > $i; done
   # /sbin/ethtool -s eth0 wol g
   echo 0 > /sys/module/snd_hda_intel/parameters/power_save
   echo max_performance > /sys/class/scsi_host/host0/link_power_management_policy
   # echo enable > /proc/acpi/ibm/bluetooth
   policy
else
   hal-disable-polling --device /dev/scd0
   # echo 5 > /proc/sys/vm/laptop_mode
   echo 1 > /sys/devices/system/cpu/sched_mc_power_savings
   # /sbin/hdparm -B 254 -S 252 /dev/sda
   echo 1500 > /proc/sys/vm/dirty_writeback_centisecs
   # for i in /sys/bus/usb/devices/*/power/autosuspend; do echo 1 > $i; done
   # /sbin/ethtool -s eth0 wol d
   echo 1 > /sys/module/snd_hda_intel/parameters/power_save
   echo min_power > /sys/class/scsi_host/host0/link_power_management_policy
   # killall beagled
   # echo disable > /proc/acpi/ibm/bluetooth
fi

------------------------------------------------------------------------------------------------
# ACPID config when switching to and from
# battery mode.
# /etc/acpi/events/battery.conf

event=battery.*
action="">

--
Paulo Roma Cavalcanti
LCG - UFRJ

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