Samsung N140

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This article provides information about installing and setting up Arch Linux on the Samsung N140. It is also relevant for the Samsung N130 which is identical except for the omission of Bluetooth and stereo speakers (and possibly a different battery capacity). There are versions of the N130 which include a 3G cellular modem, available from Vodafone and China Mobile. The Samsung NC10 is similar but not identical to the N140, so you may or may not find useful information on that page.

Issues

BIOS Issues

SATA exception, freeze, reset

Note: Patches addressing this problem have been included in the kernel since version 2.6.34rc1. Please test and report.

A BIOS problem causes a SATA hardreset shortly after boot. This is unresolved up to Samsung N140 BIOS 05CU, and Samsung N130 BIOS 06CM. See http://bugzilla.kernel.org/show_bug.cgi?id=14314, http://bugzilla.kernel.org/show_bug.cgi?id=13416, http://lkml.indiana.edu/hypermail/linux/kernel/0908.2/02809.html and http://lkml.indiana.edu/hypermail/linux/kernel/0911.3/01604.html .

A summary of the status as currently understood:

About 5 minutes after boot or resume, the BIOS switches on some power saving features which were not enabled at boot. It enables additional (sleepier) processor C-states, and sends power management instructions to the HDD. It does these behind the operating system's back -- not using ACPI, which would be handled correctly by Linux. Instead the sudden change results in a SATA exception at the first disk access following the switch. At that point the SATA driver resets the disk to resolve the problem. The result: the user sees a complete system freeze for about 30 seconds, after which operation of the machine continues normally. This can occur during the periodic fsck at boot if it is running at switch time. Either Samsung needs to be convinced to fix the BIOS, or the Linux kernel needs to be modified to behave more gracefully (Windows doesn't freeze noticeably if at all).

It has been reported that some OpenSUSE kernels [1] do not freeze and testing is progress in the Arch Forums. The patch libata-ata_piix-clear-spurious-IRQ has been reported to resolve the freezing problem (Hint: to look at the rpm use rpmextract, and then untar config.tar.bz2 and patches.*.tar.bz2). Until a final kernel patch is created this patch offers an interim solution to the problem and details are given below on how to include it in a custom kernel.

The N140 and N130 BIOSes have Phoenix FailSafe (you have been warned). It's not clear if the SATA problem has any relation to this.

Version 01CM of the N130 BIOS has been reported to not cause freezes, unlike all later ones which do.

Reports about the N130 02II and 02HI BIOSes (for the cellular modem versions) are not yet available.

This problem is hazardous for your filesystem so take precautions. For example use ext3 (not ext4) with option data=journal and install backup software.

No backlight setting via ACPI

A workaround is to use "setpci" as shown below.

Alternatively there is a kernel patch (unrelated to the SATA freeze problem) available which changes the backlight brightness using SMI instead of poking PCI config space. It provides a kernel module called "samsung-laptop". Interestingly we see from a version of this patch which is included in OpenSUSE 11.1 that a special (as yet unreleased?) BIOS for the N130 can be informed that the OS is Linux. The effect of this hasn't been published. Suggestion: run the samsung-laptop module with its debug parameter set to 1 to check whether it does anything at all.

No key releases for some Fn keys

Some of the Fn keys give key press events but no key releases. This problem was also seen on the NC10 and NC20. A workaround is given below. For kernels 2.6.32 and later this can be done from userspace.

Software issues

Frequent wireless disconnects

With kernel 2.6.31 ath9k wifi exhibits frequent disconnects and reconnects. See http://bugzilla.kernel.org/show_bug.cgi?id=14267. Earlier and later kernels are better.

Screen flickering and blackouts

Some problems have been reported with KMS enabled for some 2.6.32 kernels. This problem is not specific to the Samsung N130/N140 -- it also affects others using Intel graphics drivers. Until the software is fixed a workaround is to disable powersave mode. It expected that this issue will be resolved in kernel 2.6.33.

Installation

Do the standard Arch installation procedure from the ARCH CD ISO using an external USB CDROM drive. Alternatively boot the Arch installer from a USB flash drive.

For initial installation and testing you should use the standard Arch kernel. Subsequently (just until 2.6.34 moves to [core]) you should install the 2.6.34 kernel from [testing] http://repos.archlinux.org/wsvn/packages/kernel26/repos/testing-i686/ in order to resolve the SATA problem described above.

A number of users have used a custom kernel for the following reasons:

  • to investigate/resolve the SATA problem (up to 2.6.33)
  • to boot with a minimal kernel containing just the required modules and without an initial ramdisk.

Kernel 2.6.34 from testing

Either enable [testing] in pacman.conf (if you understand the implications) or obtain the testing kernel PKGBUILD and other files from http://repos.archlinux.org/wsvn/packages/kernel26/repos/testing-i686/ . Compile with makepkg and install with pacman -U.

Custom kernel: without initrd (AUR)

An AUR package kernel26-n130 is available. In this kernel most drivers are compiled in and there is no initial ramdisk. The drivers for cpu frequency scaling (acpi-cpufreq), wifi (ath9k, rtl8192e) and webcam (uvcvideo) are compiled as modules (i.e. not compiled in) so they can be inserted or removed from the kernel to enable or disable those features. MODULES in /etc/rc.conf can be used to enable or disable loading at boot.

Prepare the directory

$ mkdir ~/builds
$ mkdir ~/builds/kernel26-n130
$ cd ~/builds/kernel26-n130

Get the AUR package and untar it

$ wget http://aur.archlinux.org/packages/kernel26-n130/kernel26-n130.tar.gz
$ tar zxvf kernel26-n130.tar.gz
$ cd kernel26-n130

At this point you can edit the PKGBUILD file if you need to (i) change the name or version number, (ii) change options or (iii) add additional patches.

Edit PKGBUILD and make sure _USE_LIBATA_PATCH is set to 0. This patch is not needed with kernel 2.6.34 or later. Don't experiment with BFS at this point.

_USE_LIBATA_PATCH=0
...
_USE_BFS=0

Compile it (this will take some time...):

$ makepkg -s

Install the created .pkg.tar.gz file in the normal pacman way

$ sudo pacman -U kernel26-n130-2.6.34.1-3.pkg.tar.gz   (or whatever the created .pkg.tar.gz file is called)

Then, assuming you are using GRUB, insert a new item in your Template:Filename to boot the new kernel "kernel26-N130". Note that no initrd line is necessary for this kernel.

# (0) Arch Linux N130
title  Arch Linux Custom N130 Kernel
root   (hd0,YOURROOT-1)
kernel /boot/vmlinuz26-N130 root=/dev/sdaYOURROOT resume=/dev/sdaYOURSWAP ro quiet

And reboot. If you have problems the standard Arch kernel is still installed and selectable from the GRUB menu.

For GRUB2 Template:Filename the syntax looks like this (sda1 = your root partition; sda2 = your swap partition)

menuentry "Arch Linux N130" {
        set root=(hd0,1)
        linux /boot/vmlinuz26-N130 root=/dev/sda1 resume=/dev/sda2 ro quiet 
}
Note: The kernel26-n130 has the i915 module compiled in with KMS enabled by default. There is no need to set up KMS as described below unless you wish to disable it.

Custom kernel: Arch standard plus libata patch

The following method can be used for kernels up to 2.6.33. Patching is unnecessary from 2.6.34 onwards.

A custom kernel is compiled which is as close as possible to the standard Arch kernel. The only required change is to apply the patch libata-ata_piix-clear-spurious-IRQ to address the SATA problem discussed above.

$ sudo abs
$ cp -a /var/abs/core/kernel26 ~/builds/kernel26-n140
  • Change PKGBUILD as follows:
--- PKGBUILD
+++ PKGBUILD.new
@@ -1,8 +1,8 @@
 # $Id: PKGBUILD 69948 2010-02-23 18:46:27Z tpowa $
 # Maintainer: Tobias Powalowski <tpowa@archlinux.org>
 # Maintainer: Thomas Baechler <thomas@archlinux.org>
-pkgbase="kernel26"
-pkgname=('kernel26' 'kernel26-firmware' 'kernel26-headers') # Build stock -ARCH kernel
+pkgbase="kernel26-n140"
+pkgname=('kernel26-n140' 'kernel26-n140-firmware' 'kernel26-n140-headers') # Build stock -ARCH kernel
 # pkgname=kernel26-custom       # Build kernel with a different name
 _kernelname=${pkgname#kernel26}
 _basekernel=2.6.32
@@ -17,12 +17,14 @@ source=(ftp://ftp.kernel.org/pub/linux/k
         # the main kernel config files
         config config.x86_64
         # standard config files for mkinitcpio ramdisk
-        kernel26.preset)
+        kernel26.preset
+        libata-ata_piix-clear-spurious-IRQ)
 md5sums=('260551284ac224c3a43c4adac7df4879'
          'a0a10c99eead1fa8bc05c03f7f18db36'
          'c114c5d89622a93165bb948d62d966b5'
          '5c91374d56f115ba4324978d5b002711'
-         '25584700a0a679542929c4bed31433b6')
+         '25584700a0a679542929c4bed31433b6'
+         'd679ed71c2d6f367c7b1f65e82d817fa')
 
 build() {
   cd ${srcdir}/linux-$_basekernel
@@ -30,6 +32,9 @@ build() {
   # See http://projects.archlinux.org/linux-2.6-ARCH.git/
   patch -Np1 -i ${srcdir}/${_patchname} || return 1
 
+  # Patch for Samsung N130/N140
+  patch -Np1 -i ${srcdir}/libata-ata_piix-clear-spurious-IRQ   || return 1
+
   if [ "$CARCH" = "x86_64" ]; then
     cat ../config.x86_64 >./.config
   else
@@ -57,7 +62,7 @@ build() {
   make bzImage modules || return 1
 }
 
-package_kernel26() {
+package_kernel26-n140() {
   pkgdesc="The Linux Kernel and modules"
   groups=('base')
   backup=(etc/mkinitcpio.d/${pkgname}.preset)
@@ -104,7 +109,7 @@ package_kernel26() {
   rm -rf ${pkgdir}/lib/firmware
 }
 
-package_kernel26-headers() {
+package_kernel26-n140-headers() {
   pkgdesc="Header files and scripts for building modules for kernel26"
   mkdir -p ${pkgdir}/lib/modules/${_kernver}
   cd ${pkgdir}/lib/modules/${_kernver}
@@ -204,7 +209,7 @@ package_kernel26-headers() {
   rm -rf ${pkgdir}/usr/src/linux-${_kernver}/arch/{alpha,arm,arm26,avr32,blackfin,cris,frv,h8300,ia64,m32r,m68k,m68knommu,mips,microblaze,mn10300,parisc,powerpc,ppc,s390,sh,sh64,sparc,sparc64,um,v850,xtensa}
 }
 
-package_kernel26-firmware() {
+package_kernel26-n140-firmware() {
   pkgdesc="The included firmware files of the Linux Kernel"
   groups=('base')

  • compile, install it and add new section in Template:Filename, identical to the standard entry but with kernel26 replaced by kernel26-n140. Reboot.

Configure your installation

Ethernet

RTL8101e/8102e fast ethernet. Works out of the box.

Wifi

The supplied wifi device is either an Atheros AR9285 (PCI ID = 168c:002b) (European markets) or a Realtek RTL8192E (US and UK markets).

Atheros AR9285

02:00.0 Network controller [0280]: Atheros Communications Inc. AR9285 Wireless Network Adapter (PCI-Express) [168c:002b] (rev 01)

The kernel module for this device is "ath9k" (AR9285 is supported since 2.6.29).

Kernels 2.6.30 and 2.6.32-rcN release candidates seem to work fine. However with kernel 2.6.31 the wireless connection exhibits frequent disconnects and reattachments, resulting in periods of bad througput and periods of good throughput. There is no sign of any patches for 2.6.31.y to fix this regression. Complain to linux-wireless@vger.kernel.org. To get it working either downgrade to 2.6.30 or preferably upgrade to 2.6.32.

The following patch was included in 2.6.32 just before the final release: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=54ab040d24904d1fa2c0a6a27936b7c56a4efb24 . It disables PS (power saving) mode by default, since this mode was found to have problems. See here http://bugzilla.kernel.org/show_bug.cgi?id=14267 . PS mode can also be disabled with the following command, which can be placed in Template:Filename:

iwconfig wlan0 power off

Realtek RTL8192E

Open source driver

The native Linux driver for this wireless device is still in preparation, but it is available as a kernel module "rtl8192e" in "staging" -- i.e. in preparation for inclusion in the kernel and available to try out, but likely to still have some problems. It has been reported as working [2]. Firmware is required. See http://lkml.org/lkml/2009/12/15/410 and http://git.kernel.org/?p=linux/kernel/git/gregkh/firmware.git;a=summary .

Install the firmware like this:

$ sudo pacman -S git
$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/firmware.git
$ sudo cp -a firmware/RTL8192E /lib/firmware
$ rm -fr firmware

Alternatively use a web browser on another computer to save firmware-407f318.tar.gz and transfer the file (e.g. on a USB flash drive) to the Samsung N130/140. Then

$ tar zxvf firmware-407f318.tar.gz
$ sudo mkdir /lib/firmware/RTL8192E
$ sudo cp -a firmware-407f318/*.img /lib/firmware/RTL8192E

Then

$ md5sum /lib/firmware/RTL8192E/*

should return

bb9f64de23939ec247d15dfbeb0ed91e  /lib/firmware/RTL8192E/boot.img
db83def0338769de1d4658a00b6f738d  /lib/firmware/RTL8192E/data.img
0034020e5a32571f486849aa90a389a7  /lib/firmware/RTL8192E/main.img

On rebooting, the kernel messages (visible with "dmesg") should now indicate that rtl819xE finds the firmware for loading into the device.

Ndiswrapper

It has been reported as working with ndiswrapper which makes use of the closed source Windows driver under Linux.

Cellular 3G Modem

Specifications required

Graphics Adapter

The video controller is an Intel chipset that works with the xf86-video-intel driver.

00:02.0 VGA compatible controller [0300]: Intel Corporation Mobile 945GME Express Integrated Graphics Controller [8086:27ae] (rev 03)
00:02.1 Display controller [0380]: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller [8086:27a6] (rev 03)

Kernel Mode Setting

See also Intel#KMS_.28Kernel_Mode_Setting.29.

KMS works providing real consoles at the native LCD resolution, 1024x600. There is a known problem with 2.6.32 kernels (later release candidates up to at least release 2.6.32.8), which results in screen flickering and blackouts about 5 minutes after resuming from suspend-to-RAM or suspend-to-disk.

Note: If you encounter screen flickering or blackouts with KMS enabled, try setting i915.powersave=0 as a kernel boot option.
Note: Since version 2.10.0 of xf86-video-intel, support for UMS has been removed from the intel driver. This means that KMS is a requirement now.

Method A

If you are using a kernel with no inital ramdisk and you can simply add the required options to the GRUB kernel line:h

# (0) Arch Linux N130
title  Arch Linux Custom N130 Kernel
root   (hd0,YOURROOT-1)
kernel /boot/vmlinuz26-N130 root=/dev/sdaYOURROOT resume=/dev/sdaYOURSWAP ro quiet i915.powersave=0 i915.modeset=1

Method B

If you are using an initial ramdisk (either the standard kernel or the custom kernel method B above) then do the following:

Edit Template:Filename:

       options i915 powersave=0 
       options i915 modeset=1

Edit Template:Filename:

       MODULES="intel_agp i915"
       FILES="/etc/modprobe.d/modprobe.conf"

Put keymap early in Template:Filename HOOKS. Regenerate the init ramdisk for the kernel(s) you are running:

       $ mkinitcpio -p kernel26
       or 
       $ mkinitcpio -p kernel26-n140

Remove any vga= or video= from grub Template:Filename kernel line, and reboot.

KMS with KDE

With earlier versions of KDE, on logout it returned to the F1 real console instead of to KDM. Uncommenting this entry in Template:Filename solved the problem:

 TerminateServer=true

This setting is now the default.

Backlight Brightness

xbacklight does not work currently. However the brightness can be set with the following command

setpci -s 00:02.1 F4.B=hh

where hh is the level of brightness, in the range 00 to FF. Don't set it to zero because your backlight will turn off!

Note this does not require the samsung-laptop patch mentioned above.

Use the following script to increase and decrease the brightness. Put it in /sbin/backlight for example. Use xbindkeys to bind commands to the backlight Fn keys. Obtain sudo permission for user to use those commands with visudo.

 #!/bin/bash
 # increase/decrease/set/get the backlight brightness (range 0-255) by 16
 #
 #get current brightness in hex and convert to decimal
 var1=`setpci -s 00:02.1 F4.B`
 var1d=$((0x$var1))
 case "$1" in
       up)
               #calculate new brightness
               var2=`echo "ibase=10; obase=16; a=($var1d+16);if (a<255) print a else print 255" | bc`
               echo "$0: increasing brightness from 0x$var1 to 0x$var2"
               setpci -s 00:02.1 F4.B=$var2
               ;;
       down)
               #calculate new brightness
               var2=`echo "ibase=10; obase=16; a=($var1d-16);if (a>15) print a else print 15" | bc`
               echo "$0: decreasing brightness from 0x$var1 to 0x$var2"
               setpci -s 00:02.1 F4.B=$var2
               ;;
       set)
               #n.b. this does allow "set 0" i.e. backlight off
               echo "$0: setting brightness to 0x$2"
               setpci -s 00:02.1 F4.B=$2
               ;;
       get)
               echo "$0: current brightness is 0x$var1"
               ;;
       toggle)
               if [ $var1d -eq 0 ] ; then
                       echo "toggling up"
                       setpci -s 00:02.1 F4.B=FF
               else
                       echo "toggling down"
                       setpci -s 00:02.1 F4.B=0
               fi
               ;;
       *)
               echo "usage: $0 {up|down|set <val>|get|toggle}"
               ;;
 esac
 exit 0

External VGA

External VGA works out of the box with xrandr / krandrtray. Tested at 1920x1080 resolution.

Audio

The audio device is an Intel HD.

00:1b.0 Audio device [0403]: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller [8086:27d8] (rev 02)

Suspend and Hibernate

Suspend to RAM with pm-suspend works.

It is most useful to trigger suspends using acpid.

To catch the "sleep" function key, edit Template:Filename so that the button/sleep) event calls /usr/sbin/pm-suspend (instead of "echo mem > /sys/power/state" which may leave wifi down after resume):

     button/sleep)
        case "$2" in
            SLPB)   logger "Sleep button pressed, suspending to RAM"
                    /usr/sbin/pm-suspend
                    ;;
            *)      logger "ACPI action undefined: $2"
                    ;;
        esac
        ;;

When catching the lid closure, the button/lid event will be seen twice -- once on suspend and again on resume. So use the lid state to distinguish between these so that pm-suspend is not triggered twice:

Enter the following lines in Template:Filename:

    button/lid)
       if [ `/bin/awk '{print $2}' /proc/acpi/button/lid/LID0/state` = closed ]; then
           /usr/sbin/pm-suspend
       fi
       ;;

Hibernate works correctly (see pm-utils article).

If you are a KDE4 user you can take advantage of powerdevil (included in kdemod-core/kdemod-kdebase-workspace since release 4.2) to manipulate the screen brightness, cpu scaling and hibernate. Suspend from KDE works too, but if you are using handler.sh to suspend on the button/lid and button/sleep acpi events, then KDE only needs to lock the screen. Note that cpu scaling requires acpi-cpufreq module to be loaded in MODULES in /etc/rc.conf.

Fn Keys

Firstly edit Template:Filename and insert N140 into the list where you see NC10 already.

Now in a real console

 showkey

will show presses for the function keys, but no releases for some of them.

This is a BIOS issue which was also found on the Samsung NC10. A workaround quirk was put in the kernel in atkbd.c for the NC10. Patching this routine to apply the same quirk also works for the N140, and is recommended for 2.6.31 and earlier. However for 2.6.32 and later (i.e. any current Arch installation) there is a much simpler solution because this quirk can now be applied from user space. Simply edit Template:Filename and add the following line:

 echo 130,131,132,134,136,137,179,247,249 > /sys/devices/platform/i8042/serio0/force_release

After this is run, doing "showkey" in a real console will show key presses and releases.

Binding Fn keys with xbindkeys

The following has been tested with KDE, but should also work for other DEs.

To bind the Fn keys to action, read Extra_Keyboard_Keys#The_quick_way and also Extra Keyboard Keys in Xorg.

The suspend key (Fn+ESC) and disable touchpad (Fn+F10) keys, numlock, scroll lock, volume controls and mute work out of the box.

Note, that suspend key is handled in Template:Filename (see "button/sleep" case entry) as shown above.

1) install xbindkeys

 pacman -S xbindkeys

2) check the key values with

 xbindkeys -mk

3) edit .xbindkeysrc

 "sudo /sbin/backlight up"
     m:0x0 + c:233
 "sudo /sbin/backlight down"
     m:0x0 + c:232
 "/home/user/bin/systeminfo_battery"
     m:0x0 + c:244
 "sudo /sbin/backlight toggle"
     m:0x0 + c:156
 "/home/user/bin/systeminfo_disk"
     m:0x0 + c:157
 "/home/user/bin/systeminfo_cpu"
     m:0x0 + c:210
 "/home/user/bin/systeminfo_wifi"
     m:0x0 + c:246

4) run xbindkeys, and try it out

xbindkeys

For KDE4 put a link to Template:Filename in Template:Filename

 ln -s /usr/bin/xbindkeys ~/.kde4/Autostart/xbindkeys.link

The Fn+F3 ("Euro") key: here Samsung implemented what has been called an entertaingly hilarious hack: http://lists.freedesktop.org/archives/hal/2009-August/013536.html ROFL! Does anyone know a practical use for this key? Fortunately some (eurozone) models have a real Euro key as well.

Binding Fn keys in Openbox

In Openbox one can use the internal keybind setup instead of xbindkeys. Here is an excerpt from rc.xml:

    <keybind key="XF86Battery">
      <action name="Execute">
        <command>~/.PersonalBin/batteryDisplay</command>
      </action>
    </keybind>
    <keybind key="XF86Display">
      <action name="Execute">
        <command>~/.PersonalBin/monitor</command>
      </action>
    </keybind>
    <keybind key="XF86Launch1">
      <action name="Execute">
        <command>~/.PersonalBin/brightnessToggle</command>
      </action>
    </keybind>
    <keybind key="XF86Launch2">
      <action name="Execute">
        <command>nice python ~/.config/openbox/scripts/checkmail.py --update</command>
      </action>
    </keybind>
    <keybind key="XF86Launch3">
      <action name="Execute">
        <command>~/.PersonalBin/powersaveToggle</command>
      </action>
    </keybind>
    </keybind>
    <keybind key="XF86AudioMute">
      <action name="Execute">
        <command>~/.PersonalBin/volume mute</command>
      </action>
    </keybind>
    <keybind key="XF86WLAN">
      <action name="Execute">
        <command>~/.PersonalBin/wlanToggle</command>
      </action>
    </keybind>
    <keybind key="XF86AudioLowerVolume">
      <action name="Execute">
        <command>~/.PersonalBin/volume -</command>
      </action>
    </keybind>
    <keybind key="XF86AudioRaiseVolume">
      <action name="Execute">
        <command>~/.PersonalBin/volume +</command>
      </action>
    </keybind>
    <keybind key="XF86MonBrightnessDown">
      <action name="PreviousWindow">
        <bar>no</bar>
        <allDesktops>yes</allDesktops>
        <finalactions>
          <action name="Focus"/>
          <action name="Raise"/>
        </finalactions>
      </action>
    </keybind>
    <keybind key="XF86MonBrightnessUp">
      <action name="NextWindow">
        <bar>no</bar>
        <allDesktops>yes</allDesktops>
        <finalactions>
          <action name="Focus"/>
          <action name="Raise"/>
        </finalactions>
      </action>
    </keybind>

Saving Power

Read Laptop#Power_Management

Read Lightweight Applications

Note: Caution is advised here with hdparm settings because the issue with SATA freezing is related to power management and spindowns. Before you tune the Samsung N130/N140 to minimize power consumption it is strongly recommended that you resolve the SATA freezing issue as discussed above.

The Samsung N130/N140 contains a 1.6 GHz Intel Atom ULV (ultra low voltage) N270 processor, designed for low power consumption. The power consumption of the netbook (not just the processor) can be as low as 6W on idle with HDD spun down, although a typical figure under normal usage would be considerably higher.

Obviously the battery life depends on battery capacity as well as power consumption. The supplied battery varies in different markets. This list is a guideline only. Do not rely on this information before purchase -- check with YOUR vendor and update this wiki if it is incorrect:

Voltage 11.1V

N130             = 4000mAh [44Wh] (most markets), 5200mAh [57Wh] (Sweden)
N130 (Vodafone)  = ? [?] (Spain)
N130 (CMCC)      = ? [?] (China)
N140             = 5200mAh [57Wh] (US, Germany, France, Sweden), 5900mAh [65Wh] (UK)
Extended battery = 7800mAh [86Wh]

Install powertop which is a very useful tool for measuring and tuning power consumption, and htop which is useful for checking the CPU and memory usage of running processes

# pacman -S powertop htop

Enable CPU frequency scaling (P-states) by loading the driver module "acpi-cpufreq". This is most conveniently done in Template:Filename:

MODULES=(acpi-cpufreq ... )

Select the CPU frequency governor by adding the following lines to Template:Filename:

# Set the CPU frequency scaling governor for each core
echo "ondemand" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
echo "ondemand" > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor
Note: Contrary to the advice in many places "hdparm -B 255 /dev/sda" does NOT necessarily turn off advanced power management. What happens depends on the disk model. With the Samsung HM160HI disk 255 results in very frequent spindowns