Dennis Núñez-Fernández

BSc in Electronic Engineering, Universidad Nacional de Ingeniería (UNI)


Add graphical environment with Xephyr Disp. Server to Parallella Board

Requirements: Ubuntu PC and Parallella Board.

First you should to set all configurations of the previous post Add Graphical Environment (https://dennishnf.github.io/posts/technical/2015-07_add_graphical_environment.html).


Install Xephyr in your Ubuntu PC:

$ sudo apt-get install xserver-xephyr


Able or Disable PCManFM Desktop mode:

I recommend to disable 'PCManFM Desktop mode' for faster displaying. Edit the next files (On Parallella Board):

$ sudo nano /etc/xdg/lxsession/LXDE/autostart

$ sudo nano ~/.config/lxsession/LXDE/autostart

, to able or disable 'PCManFM Desktop mode', in both files add or delete respectively the next line, and save:

@pcmanfm --desktop --profile LXDE


Set a background image:

Put a background image file in your home directory ( e.g. /home/technical/lxde_wallpaper.png ). Then edit the next files (On Parallella Board):

$ sudo nano /etc/xdg/lxsession/LXDE/autostart

$ sudo nano ~/.config/lxsession/LXDE/autostart

, add this line to the bottom of the both files:

@feh --bg-fill /home/technical/lxde_wallpaper.png


After set PCManFM Desktop mode and background image:

On Parallella Board:

$ sync $ sudo reboot


Running

Notice that my PC IP is 192.168.1.101, and Parallella uses 192.168.1.110. Obviously you have to adjust those to your values.

Check your IP here if you are using Ubuntu: https://sliceoflinux.wordpress.com/2010/04/02/como-averiguar-la-ip-de-un-ordenador-con-ubuntu/.


1.Open Xephyr

Launch Xephyr Server in your Ubuntu PC. Open a terminal and type:

$ Xephyr -ac -br -keybd ephyr,,,xkbmodel=pc105,xkblayout=es -noreset -screen 1280x720 :1

You can change the value 1280x720 to: 640x489, 1280x720, 1366x768, ...


2.Connect to Parallella

Open a terminal in Ubuntu PC and type:

$ ssh -X parallella@10.42.0.50


3.Export Parallella Display

In the terminal that you are connected to Parallella, type:

$ export DISPLAY=192.168.1.101:1

You just tell that DISPLAY should be run to the remote machine with the IP (my PC IP is 192.168.1.101) and DISPLAY :1 which is the Xephyr Session. GNOME’s display should be :0, and is used.


4.Run XServer

In ssh terminal, that you are connected to Parallella, try to run your graphical environment. I have a default LXDE.

$ startlxde


Another option for steps 2, 3 and 4

Instead of the points 2 and 3, in Ubuntu PC:

$ DISPLAY=:1 ssh -Y parallella@10.42.0.50

Then continue with step 4, in ssh terminal connected to Parallella:

$ startlxde


Result

Start with Xephyr Display Server and disable 'PCManFM Desktop mode' and set a background image:


Resources

- http://worldofgnome.org/howto-export-rpi-display-to-gnome/.

- http://elinux.org/Parallella_Linaro_Nano#How_to_Install_lightweight_X_environment.