XFCE

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Xfce is a lightweight but powerful desktop environment that will work well on the XO. The following is a tutorial for using Xfce on the XO based on the article from the Free Like GNU article and several forum posts.

Preamble

Please read the following steps before proceeding to make sure you understand what is involved! We take no responsibility for you making your XO unbootable. Although the process is reasonably safe for your XO, you should know how to and have the ability to wipe the XO and start fresh using a USB stick in case you get into trouble!

Please also note that xfce and other third-party modifications (all non .xo bundled applications) to your XO may be rendered inoperative when you upgrade the base OS to a new build. (See http://dev.laptop.org/ticket/6317)

Instructions

Get Root

  • Establish a connection to the internet. You will need the ability to connect to the internet to retrieve and update files from the OPLC's repositories. "yum" is the command that will retrieve the files you request and it will automatically install them. You will need to have "root" access to use yum.
  • Get "root": Use the terminal activity and type su at the prompt and hit the return key. Your command prompt will now end with "#" this means you have "root" and can change any file on the computer.
$ su
#

Install Packages

Install xfce, this will give you a very basic desktop environment and the ability to customize it. This will download about 40MBs to RAM then install the files automatically. Make sure, no other Activity is running. Otherwise during installation you will get 'error: can't allocate memory'. To proceed, stop Terminal Activity, reboot, restart the process. If you get a "Socket Error" that returns you to a prompt, use the up arrow to restore your original command and enter to restart the process. 

# yum install xfdesktop xfce-utils xfce-mcs-plugins xfce4-session

Optional packages: xmms (audio player), orage (calendar), xfce-mixer (volume control), system-config-date (set datetime/timezone), genmon (generic monitor - can be used to output battery status, for example), systemload (shows CPU and memory usage) 

# yum install xmms orage xfce4-mixer system-config-date xfce4-genmon-plugin xfce4-systemload-plugin


Install Firefox

Installing firefox requires that you remove its exclusion from the XO's repository list Open the repository file with the following command: 

# nano /etc/yum.repos.d/olpc-koji-ship2.repo

NOTE: in the latest builds (here tested on candidate-691) the command should be: 

# nano /etc/yum.repos.d/olpc-koji-update1.repo

Remove the firefox entry from the last line so it looks like this: 

exclude=seamonkey,mozplugger,kdebase,kernel

then save using CTRL+X and confirm with "y" Install Firefox by running this command 

# yum install firefox

Manage WiFi Networks

You can use wifi-radar to manage your wireless connection within xfce 

# yum install wifi-radar

You can run wifi-radar through the xfce menu under "Networking". After running it once, a file will be created at /etc/wifi-radar/wifi-radar.conf. Open this file in a text editor, and change the line which reads: 

interface = eth1

to read: 

interface = eth0

Now, running wifi-radar should allow you to see the available wireless networks and connect to one. You may need to disable the default wireless network manager, by running: 

# /etc/init.d/NetworkManager stop

You can permanently disable network manager by 

# /sbin/chkconfig NetworkManager off

If you want to run wifi-radar as a daemon which will automatically connect to a preferred network: 

$ wifi-radar -d

Manage WPA2 and WPA Keys with XFCE

You can connect to Wireless Access Points using WPA and WPA2 keys. Wifi-Radar requires WPA-Drivers. Set WPA-Driver to "wext". Following solution don't require wifi-radar, thus work stand-alone for preferred WiFi-connection. wpa_supplicant is installed. Otherwise use yum install wpa_supplicant.

Add WPA Keys

Prepare your wireless network configuration. Edits can be added muliple for various connection types. 

# nano /etc/wpa_supplicant/wpa_supplicant.conf

Adding following lines for WPA2 or WPA1 keys

WPA2 Connect Entry 

network={
	ssid="MyHome WiFi Name"
	scan_ssid=1
	proto=RSN
	key_mgmt=WPA-PSK
	pairwise=CCMP
	group=CCMP
	psk="My Paraphrase"
}

WPA1 Connect Entry 

network={
       ssid="MyHome WiFi Name"
       scan_ssid=1
       proto=WPA
       key_mgmt=WPA-PSK
       pairwise=CCMP TKIP
       group=CCMP TKIP
       psk="My Paraphare"
}

Using WPA, options pairwise and group may vary between 'CCMP' or 'TKIP'. Get Wireless Access Point settings by running command line program 'iwlist scanning', looking for preferred wifi connection. 'CCMP' seems preferrable.

Edit sysconfig

Edit file 

# nano /etc/sysconfig/wpa_supplicant

Read line INTERFACE="-iwlan0". Set to 

INTERFACES="-ieth0"

Restart eth0

For some reason you must reset network device while booting. 

# nano /etc/rc.local

After read "touch /var/lock/subsys/local" insert 

ifdown eth0
ifup eth0

Disable NetworkManager

Disable network manager permanently like you did for wifi-radar by 

# chkconfig NetworkManager off

Install wpa_supplicant demon

Enable wpa_supplicant permanently by 

# chkconfig --level 2345 wpa_supplicant on

Your system must be rebooted to access the web.

Xfce startup message

While launching Xfce there is a dhcp warning 'Could not lookup ...'. Continue anyway or follow given instructions. All works very fine now.


Screen Brightness/Rotation, Sound Volume, and Battery Status Control

The keys on your XO can be easily made functional again by installing the rpm on this page: olpc-keybind. This RPM contains the scripts to perform the operations and the instructions to configure your default olpc user account to use them.

This rpm depends on xbindkeys. Because this rpm doesnt yet exist in the official repositry you have to do the following in a terminal (as root) to install it: 

yum install xbindkeys
rpm -Uhv http://favias.org/files/olpc-keybind-1-2.noarch.rpm

To remove this functionality the following command as root in terminal will suffice: 

yum remove olpc-keybind xbindkeys

Screen rotation note: Rotation does not automatically resize the windows. If you are using fullscreen mode this may be fixed by pressing Alt-F11 twice.

NOTE: On error 'scriplet failed' run as root /usr/bin/olpc-keybind manually. Run xbindkeys & for testing screen rotation. You can add /usr/bin/xbindkeys to Xfce Autostarted Applications via Setting Menue.

Displaying Battery Status in panel

  • Install olpc-keybind rpm for the battery-status binary it provides
  • use genmon (see above) to display the battery status in a toolbar
    • right-click on a blank spot on an Xfce toolbar, chose Add Item, select Generic Monitor and clicked Add
    • right-click the new Generic Monitor item, select Properties, and apply the following settings:
      • Command: battery-status
      • Label: B
      • Period: 300

Mounting Removable Filesystems

  1. Insert SD card or usb drive.
  2. Run thunar, the Xfce File Manager.
  3. The removable media should appear in the left-hand column. Click on it to mount it. A df will show that it has been mounted in the appropriate place (/mount/VOLUME_NAME)
  4. To unmount, right click on the media name in the same place and choose unmount.


Change default desktop

Turn Xfce to default desktop

In /home/olpc/ create a copy of .xsession-example called .xsession: 

#cp /home/olpc/.xsession-example /home/olpc/.xsession

Edit the .xsession file to launch Xfce on startup: 

# nano /home/olpc/.xsession

Find the commented line that reads #exec xterm - below that line, add the following code: 

exec startxfce4
  • use CTRL+X to save and exit
  • use CTRL+ALT+BACKSPACE to restart X, starting Xfce


Turn back XO Sugar desktop

To make the original XO Sugar desktop the default boot again, rename the .xsession file to anything other than .xsession (.xsession.xfce for instance). Applied changes, e.g. WiFi, stay persistent.

Trouble?

Defreeze Boot Animation

If you reboot and get stuck at the XO logo (with circle around it), hold down power to shutdown then power up again.

Warning! This is advanced and can potentially screw up your boot. To bypass the boot anim manually, hold down the checkmark while turning the OLPC on, then wait for the machine to tell you to release it.

You can prevent boot freezing by disabling the startup logo animation:

  • Open the startup animation logo file /etc/init.d/0-boot-anim-start
  • Above the line saying "# i'm the child", change if os.fork() == 0: to if os.fork() == 'debug': to prevent the animation code from being executed.

XO Wipeout

In case of major trouble be prepared to wipe out your XO with an USB-Stick. This will clearly erase all data and any changes. Read and understand instructions following http://wiki.laptop.org/go/Secure_Upgrade first, before apply major changes to XO. This document is under continued construction and may contain malicious strategies.

References

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