Daniel Lange's blog (Entries tagged as ubuntu)

Ubuntu Karmic 9.10 Bluetooth UMTS Dial-up (DUN)

nospam@example.com (Daniel Lange) — Mon, 21 Dec 2009 18:10:00 +0100

Using a mobile phone's Bluetooth Dial-up network (DUN) to connect to the Internet (UMTS/GPRS) while on the road is quite convenient for me. Sadly so this is not supported out-of-the-box in Ubuntu Karmic 9.10 (Netbook Remix) as it uses Network-Manager to handle - well - network connections. And that is not quite there on Bluetooth managed devices yet.

While the default solution (rfcomm and Gnome-PPP) still works, it's ugly to set up. Sadly so, zillions of Ubuntu-Forum threads and blog entries still detail this solution - or the issues encountered with it along the way.

The much better solutions is using Blueman, an improved Gnome-Bluetooth primarily developed by Valmantas Palikša. It brings the right UDEV magic along to teach Network-Manager about the Bluetooth devices it handles.

Blueman Screenshot on Ubuntu Karmic 9.10 Netbook Edition

Just follow the steps on their downloads page to set up the Blueman PPA (Personal Package Archive) to get things working.

Kubuntu 9.10 (karmic) 64bit firefox java plugin

nospam@example.com (Daniel Lange) — Sun, 06 Dec 2009 18:00:00 +0100

For some unknown reason the (K)Ubuntu developers did not update the Java plugin for firefox after jaunty (yet?).

The version that Karmic (9.10) pulls out of the multiverse repository is still jaunty's (9.04).

So when you try:

apt-get install sun-java6-plugin

you'll get something like

   Reading package lists... Done
   Building dependency tree
   Reading state information... Done
   Some packages could not be installed. This may mean that you have
   requested an impossible situation or if you are using the unstable
   distribution that some required packages have not yet been created
   or been moved out of Incoming.
   The following information may help to resolve the situation:

   The following packages have unmet dependencies:
     sun-java6-plugin: Depends: sun-java6-bin (= 6-15-1) but 6-16-0ubuntu1.9.04 is to be installed
   E: Broken packages

Duh.

Actually if you have the Java Runtime Environment (JRE, package name sun-java6-jre) installed all files needed are already present.
Just not put in the right place on the filesystem.

So, run:

sudo apt-get install sun-java6-jre # install JRE if needed
sudo ln -s /usr/lib/jvm/java-6-sun/jre/lib/amd64/libnpjp2.so /usr/lib/mozilla/plugins/

This will install the JRE (if it's not already installed) and will symlink the firefox plugin for java in place so that it'll be found after a browser restart.

Fixing FreeNX / NoMachine NX keyboard glitches (e.g. ALTGr)

nospam@example.com (Daniel Lange) — Sun, 10 May 2009 13:44:18 +0200

There is a add-on technology to X or VNC called NX by an Italian company called NoMachine. It's quite useful as it speeds up working on remote desktops via slow network connections (i.e. DSL pipes) substantially.

The libraries that implement NX are released under GPLv2 by that company. A server wrapping up the libraries' functionality is available as closed source from NoMachine or as a free product (GPLv2 again) by Fabian Franz, called FreeNX.

FreeNX itself is amazing as it is written in BASH (with a few helper functions in C). It's also able to mend some of the shortcomings of the NX architecture. E.g. stock NX requires a technical user called "nx" to able to ssh into the NX server with a public/private keypair. FreeNX can work around that for more secure set-ups.

One issue I bumped into quite regularly with Linux clients and Linux hosts from different distributions/localisations is that the keymaps are not compatible. This usually results in the ALTGr key not usable, so German keyboard users can't enter a pipe ("|"), tilde ("~") or a backslash ("\") character. Also the up and down keys are usually resulting in weird characters being pasted to the shell. Now all of that makes using a shell/terminal prompt quite interesting.

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Getting dual-screen (xinerama) to work with Matrox G450/550 graphics cards and Xorg 1.5

nospam@example.com (Daniel Lange) — Sat, 25 Apr 2009 14:30:00 +0200

Gentoo finally decided to update Xorg to 1.5. Because this has very substantial changes against the previous version, some things break and there is a migration guide that you are nagged to read. After the upgrade I found that the Matrox card in one of my servers would not display xinerama anymore, i.e. I would get the same image on both screens only. This is the default behaviour for the stock Xorg mga driver. It needs a proprietary HALlib to get real dual-screen capabilities. Whilst there are a few unstable ebuilds for x11-drivers/xf86-video-mga none worked for me any better with Xinerama. The Gentoo Changelog is useless as usual. (Gentoo ebuild ChangeLogs tend to never really tell what is fixed, if you're lucky they reference a bug with a good description. But that's only if you're really lucky.)

Worse, that driver hasn't been updated by Matrox anymore since mammals took over the earth (figuratively ... 2005). This is the typical unmaintained-closed-source-drivers-make-hardware-obsolete-sooner-than-later story. Luckily the cards are quite widely used and clever people from the Open Source community have written guides (Tuxx-Home, Fkung) on how to dissect the proprietary driver and combine parts of it with the Open Source version so that it can be linked into recent X servers. Unfortunately because of the architectural changes in Xorg 1.5, following these guides will fail at the compile stage.

In the Matrox Forum of Alexander Griesser, the author of the first comprehensive Matrox driver install guide linked above, people currently mostly downgrade to previous Xorg versions to work around the issue.

But there is a better^Hworking solution already emerging ...

Continue reading "Getting dual-screen (xinerama) to work with Matrox G450/550 graphics cards and Xorg 1.5"