Samsung N150

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This article describes the installation and configuration of 64-bit Arch Linux on the Samsung N150 netbook. Based on the output from dmidecode, this material might also be useful for the N210 and N220 models.

Hardware overview

The Samsung N150 netbook is equipped with the Intel Atom N450 ("Pineview") CPU with integrated Intel GMA 3100 GPU and "Pine Trail" chipset. Unlike the prior single-core Intel Atom N2xx and Z series processors, the N450 supports the x86_64 instruction set. Although DMI information suggests the motherboard will accept up to 8 GiB RAM, the integrated memory controller in the Atom N450 can address a maximum of 2 GiB. Since the hardware is limited to a 32-bit address space, the primary benefit to running the 64-bit version of Arch on this system is to take advantage of AUR packages built on more powerful 64-bit systems belonging to the same owner.

Shipping versions of the N150 (as of early March 2010) include the "starter" edition of a proprietary operating system and therefore include only 1 GiB RAM in the form of a single DDR2 667 MhZ SODIMM, which is user-replaceable. Per the DMI information, the unit contains two mini PCI express slots, one of which is populated by the included Atheros AR9285 wireless card. Other versions of this model are apparently available with an integrated 3G WAN adapter installed in the other slot.

External connectivity provided on the system includes 3 USB 2.0 ports, a single VGA port, 10/100 Ethernet (Marvell 88E8040 PCI-E), headphone/microphone jacks, and an integrated card reader (SD/SDHC/MMC). An integrated VGA-resolution webcam is connected to the internal USB controller.

Installation

Since netbooks lack optical drives, the preferred installation mechanism is via a USB flash drive. Upon first boot into the 2009.08 installation media, the system will reboot after CPU initialization. Subsequent reboots using the same kernel will not exhibit this behavior, although booting into a later installed kernel may reboot the first time.

This article assumes the entire hard disk will be used for Arch, eliminating the manufacturer-supplied software (including the recovery partitions). It is not entirely clear which partitions are required for the recovery software to function properly: retention of the only first partition, of unknown type, is not sufficient. If a recovery mechanism for the factory-supplied software is desired, a set of recovery DVDs should be created using an external DVD burner prior to installing Arch.

Upon the first installation, cfdisk will exit with an error due to the existing partition layout extending beyond the end of the disk (using Linux default geometries). The solution is to run fdisk and create a new, empty partition table. WARNING: This operation will destroy the current hard disk partitions, effectively causing all data on the hard disk to be lost.

fdisk /dev/sda << EOF
o
w
EOF

After initializing the drive with an empty partition table, cfdisk will work properly in the Arch installer.

Device configuration

Ethernet (wired)

The Marvell 88E8040 wired 10/100 Ethernet adapter works out of the box with the default kernel. By installing NetworkManager and delaying network initialization until after the GUI is displayed, the boot process can be expedited.

Wireless networking

The Samsung N150 is sold with two different wireless cards: the Atheros AR9285 and the Realtek 8192E.

Note: the Samsung N150-Plus model can also be equipped with a Broadcom BCM4313 WiFi card.

Atheros AR9285

This wireless adapter also works out of the box, including full WPA2-PSK support via NetworkManager. Power to the transmitter can be toggled if the rfkill package is installed, if the following script is installed in /usr/local/sbin/rftoggle

#!/bin/sh

blocked=`rfkill list wlan | grep "Soft blocked: yes"`

if [ -z "$blocked" ]; then
   rfkill block wlan
else
   rfkill unblock wlan
fi

Also, this is the script that can do same function and more:

#!/bin/sh

case "$1" in
toggle)
    $0 &> /dev/null
    case "$2" in
    on)
        if [ $? -eq 1 ]; then
            rfkill unblock wifi
            $0 &> /dev/null
            if [ $? -eq 0 ]; then
                echo "Wi-Fi toggled on"
            else
                echo "Can't toggle Wi-Fi on"
                exit 2
            fi
        else
            echo "Wi-Fi already toggled on"
        fi
        ;;
    off)
        if [ $? -eq 0 ]; then
            rfkill block wifi
            $0 &> /dev/null
            if [ $? -eq 1 ]; then
                echo "Wi-Fi toggled off"
            else
                echo "Can't toggle Wi-Fi off"
                exit 3
            fi
        else
            echo "Wi-Fi already toggled off"
        fi
        ;;
    *)
        if [ $? -eq 1 ]; then
            $0 toggle on
        else
            $0 toggle off
        fi
        ;;
    esac
    ;;
*)
    rfkill list wifi | grep ': yes' &> /dev/null
    if [ $? -eq 1 ]; then
        echo "Wi-Fi is on"
    else
        echo "Wi-Fi is off"
        exit 1
    fi
    ;;
esac

Realtek 8192E

The RTL8192E driver is in the Arch kernel, but firmware is required. It is in the linux-firmware package.

Broadcom BCM4313 (Samsung N150-Plus)

Samsung N150-Plus has a newer Broadcom BCM4313 adapter with built-in bluetooth. As of kernel v2.6.37, this card works out of the box thanks to the open-source brcm80211 driver. However, on older kernels you'll need a proprietary driver (AUR: broadcom-wl or if you want to compile manually: http://www.broadcom.com/support/802.11/linux_sta.php). Bluetooth also works fine with either driver.

For more information: Broadcom wireless

Graphics

The Intel GMA 3100 GPU, embedded in the Atom 450 CPU package, works out of the box with Kernel Mode Setting. Early KMS initialization seems to improve boot speed slightly and can be enabled by adding the following to the MODULES line in /etc/mkinitcpio.conf:

MODULES="intel_agp i915"

Run mkinitcpio -p linux to make the configuration effective.

Unlike the prior Samsung N140 model, the N150 does not seem to suffer from display powersaving problems.

Once Fn keys are enabled (see below), Fn+F4 will toggle between LCD only, extended, and cloned modes automatically whenever an external screen is connected to the VGA port.

Backlight

Like other Samsung laptops and netbooks, direct ACPI control of the backlight is not possible on the N150. Instead, a script can be created to manage backlight settings by changing the PCI configuration of the display adapter. For ease of use with the Fn keys section, this script should be located at /usr/local/sbin/backlight

#!/bin/bash
# increase/decrease/set/get the backlight brightness (range 0-255)
#
 
# PCI device on which to operate
DEVICE=00:02.0

# Amount to raise/lower the backlight when called with "up" or "down"
AMOUNT=8

# Minimum backlight value reachable via "down"
MIN=1

# Default backlight level when toggling on
DEFAULT=64
 
#get current brightness in hex and convert to decimal
var1=`setpci -s $DEVICE F4.B`
var1d=$((0x$var1))
case "$1" in
       up)
               #calculate new brightness
               var2=`echo "ibase=10; obase=16; a=($var1d+$AMOUNT);if (a<255) print a else print 255" | bc`
               echo "$0: increasing brightness from 0x$var1 to 0x$var2"
               setpci -s $DEVICE F4.B=$var2
               ;;
       down)
               #calculate new brightness
               var2=`echo "ibase=10; obase=16; a=($var1d-$AMOUNT);if (a>$MIN) print a else print $MIN" | bc`
               echo "$0: decreasing brightness from 0x$var1 to 0x$var2"
               setpci -s $DEVICE F4.B=$var2
               ;;
       set)
               #n.b. this does allow "set 0" i.e. backlight off
               echo "$0: setting brightness to 0x$2"
               setpci -s $DEVICE F4.B=$2
               ;;
       get)
               echo "$0: current brightness is 0x$var1"
               ;;
       toggle)
               if [ $var1d -eq 0 ] ; then
                       echo "toggling up"
                       setpci -s $DEVICE F4.B=$DEFAULT
               else
                       echo "toggling down"
                       setpci -s $DEVICE F4.B=0
               fi
               ;;
       *)
               echo "usage: $0 {up|down|set <val>|get|toggle}"
               ;;
esac
exit 0

Audio

Intel HD Audio works out of the box on this model, although the volume for the "speaker" mixer channel needs to be increased from zero. Install the alsa-utils package to acquire an init script for restoring the volume at boot time.

For N210 owners the internal microphone might not work out of the box. You have to run the following:

# echo 0x19 0x90A70011 > /sys/class/sound/hwC0D0/user_pin_configs
# echo 1 > /sys/class/sound/hwC0D0/reconfig

Suspend to RAM (S3 sleep)

With Gnome 2.28 and the gnome-power-manager package installed, suspend-to-RAM works out of the box whenever the netbook lid is closed. The suspend process requires up to 30 seconds or so to take effect. Waking from S3 requires activating the power button under the default configuration. Waking upon opening the lid, or pressing a key, can be enabled in the BIOS.

With the realtek wireless card, wireless doesn't always come up again on suspend. Unloading and reloading the r8192e_pci module brings it back. This can also be configured automatically with Pm-utils.

From kernel 2.6.35 there is a regression that may prevent the system to comming back (experienced on N210 with 2.6.39) from suspend. The solution is, to create a file /etc/pm/sleep.d/10cpu-disable with the following content

#!/bin/sh
#
# 10cpu-disable: turn of the second CPU before suspend. 
# fixes resume problem on 2.6.35-2.6.39... on Samsung Nxxx laptops.
# bug: https://bugzilla.kernel.org/show_bug.cgi?id=21952

case "$1" in
hibernate|suspend)
echo 0 > /sys/devices/system/cpu/cpu1/online
;;
thaw|resume)
echo 1 > /sys/devices/system/cpu/cpu1/online
;;
*) exit $NA
;;
esac

Suspend to disk (hibernate)

Hibernate support with pm-utils does not work reliably. Upon resuming from hibernation, there are ELF header errors related to glibc, effectively preventing any new applications (including /sbin/shutdown) from starting. Moreover, even if this problem can be resolved, the process of resuming from the swap partition (before the errors are observed) is slightly longer than a cold boot.

With the kernel 2.6.36 series, some samsung N series machines requires to add the parameter intel_idle.max_cstate=0 to the kernel line for the hibernation/suspension to work correctly.

Touchpad

The Synaptics touchpad works for single-finger operation with scrolling along the right edge out of the box. When Fn+F10 is pressed, the BIOS automatically enables or disables the touchpad hardware. To receive notification of this event, it is useful to install the xosd package and configure a script to print a message whenever Fn+F10 is pressed (see below for Fn key configuration). This script should be saved in /usr/local/bin/report_touchpad

#!/bin/bash

FONT='-adobe-helvetica-bold-*-*-*-34-*-*-*-*-*-*-*'
DELAY=1
state=Unknown

case "$1" in
   on)
      state=Enabled
      ;;
   off)
      state=Disabled
      ;;
   *)
      echo "usage: $0 {on|off}"
      exit 2
      ;;
esac

osd_cat -A center -p middle -f $FONT -d $DELAY << EOF
Touchpad $state
EOF

exit 0

To enable tapping, the easiest solution is to install gsynaptics or gpointing-device-settingsAUR. Although the literature shipping with the netbook claims multitouch support (for two-finger tap, two-finger scroll, etc.), it does not appear to work properly.

For n220 owners (these parameters haven't been tested on n150 but it migth work), these touchpad rules enable multitouch (/etc/hal/fdi/policy/11-x11-synaptics.fdi)

<?xml version="1.0" encoding="ISO-8859-1"?>
<deviceinfo version="0.2">
        <device>
                <match key="info.capabilities" contains="input.touchpad">
                        <merge key="input.x11_driver" type="string">synaptics</merge>
                        <merge key="input.x11_options.TapButton1" type="string">1</merge>
                        <merge key="input.x11_options.TapButton2" type="string">2</merge>
                        <merge key="input.x11_options.TapButton3" type="string">3</merge>


                        <merge key="input.x11_options.SHMConfig" type="string">true</merge>

                        <merge key="input.x11_options.VertEdgeScroll" type="string">false</merge>
                        <merge key="input.x11_options.PalmDetect" type="string">false</merge>

                        <merge key="input.x11_options.VerteScrollDelta" type="string">100</merge>

                        <merge key="input.x11_options.VertTwoFingerScroll" type="string">true</merge>
                        <merge key="input.x11_options.HorizTwoFingerScroll" type="string">true</merge>
                        <merge key="input.x11_options.EmulateTwoFingerMinZ" type="string">40</merge>
                        <merge key="input.x11_options.EmulateTwoFingerMinW" type="string">5</merge>



                </match>
        </device>
</deviceinfo>

CPU frequency scaling

To improve power management to some degree, CPU frequency scaling can be enabled. This mechanism requires a few modules to be loaded at boot time from /etc/rc.conf:

MODULES=(acpi-cpufreq cpufreq-ondemand cpufreq-powersave)

Toggling between the performance, ondemand, and powersave governors can be accomplished via the following script, installed to /usr/local/sbin/cpufreq_toggle

#!/bin/bash

current=`cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor`
future=unknown

if [ "$current" == "performance" ]; then
   future="ondemand"
elif [ "$current" == "ondemand" ]; then
   future="powersave"
else
   future="performance"
fi

echo "$future" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
echo "$future" > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor

echo "$future"

For reporting the current governor choice via an on-screen display (useful if enabling the Fn+F8 performance switching shortcut), the following wrapper script can be installed as /usr/local/bin/cpufreq_toggle_osd

#!/bin/bash

FONT='-adobe-helvetica-bold-*-*-*-34-*-*-*-*-*-*-*'
DELAY=1

state=`sudo /usr/local/sbin/cpufreq_toggle`
message="CPU Performance State Unknown"

if [ "$state" == "performance" ]; then
   message="Performance Mode"
elif [ "$state" == "powersave" ]; then
   message="Low Power Mode"
elif [ "$state" == "ondemand" ]; then
   message="Automatic Mode"
fi

osd_cat -A center -p middle -f $FONT -d $DELAY << EOF
$message
EOF

exit 0

By default, the system will boot with CPU frequency scaling set to use the performance governor. To enable the ondemand governor at the end of the boot process, append the following to /etc/rc.local

echo "ondemand" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
echo "ondemand" > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor

Fn keys

Samsung Tools can be installed to quickly get the Fn key combinations work. It is available in AUR samsung-toolsAUR

Several of the special Fn key combinations work out of the box with the N150, but most do not. Unusual scancodes are reported to the kernel, which does not know how to convert these codes to keycodes natively. Worse, many of the scancodes produce a key press event without a corresponding key release event. Appending the following lines to /etc/rc.local will enable all Fn keys and map them properly:

setkeycodes e002 227   # Fn+F4 maps to switchvidmode
setkeycodes e003 236   # Fn+F2 maps to battery
setkeycodes e004 148   # Fn+F5 maps to prog1
setkeycodes e006 238   # Fn+F9 maps to wlan
setkeycodes e008 225   # Fn+Up maps to brightnessup
setkeycodes e009 224   # Fn+Dn maps to brightnessdown
setkeycodes e031 149   # Fn+F7 maps to prog2
setkeycodes e033 202   # Fn+F8 maps to prog3
setkeycodes e077 191   # Fn+F10 maps to F21 whenever the touchpad is enabled
setkeycodes e079 192   # Fn+F10 maps to F22 whenever the touchpad is disabled

# Ensure key release events occur for all except Fn+F7, which properly reports a key release for some reason
echo 130,131,132,134,136,137,179,247,249 > /sys/devices/platform/i8042/serio0/force_release

To enable hotkeys to change backlight, wireless, and system performance settings, it is necessary to give regular users certain permissions via the sudo command. Run visudo as root and add the following to the Cmnd alias specifications:

Cmnd_Alias NETBOOK_CMDS = /usr/local/sbin/backlight, /usr/local/sbin/rftoggle, /usr/local/sbin/cpufreq_toggle

Then add the following to the bottom of the file:

%users ALL=(ALL) NOPASSWD: NETBOOK_CMDS

Now custom keyboard shortcuts can be added to Gnome by means of the "Keyboard Shortcuts" preferences.

Name Command Key
Touchpad disabled /usr/local/bin/report_touchpad off Press Fn+F10 while touchpad enabled
Touchpad enabled /usr/local/bin/report_touchpad on Press Fn+F10 while touchpad disabled
Toggle CPU frequency scaling /usr/local/bin/cpufreq_toggle_osd Fn+F8
Raise backlight sudo /usr/local/sbin/backlight up Fn+Up arrow
Lower backlight sudo /usr/local/sbin/backlight down Fn+Down arrow
Toggle wireless sudo /usr/local/sbin/rftoggle Fn+F9
Toggle backlight sudo /usr/local/sbin/backlight toggle Fn+F5