cat /dev/braindump » Ubuntu

Reducing T420s Power Consumption under KDE/Linux

Thilo-Alexander Ginkel — Thu, 06 Oct 2011 19:03:52 +0000

If you own a Lenovo ThinkPad T420s (or any recent-generation notebook with a Sandy Bridge CPU) with Intel HD 3000 Graphics, this information may help you to reduce the power consumption under KDE/Linux:

Intel HD 3000 Power-Saving: Enable the following Kernel command-line options: i915.i915_enable_rc6=1 i915.i915_enable_fbc=1 i915.lvds_downclock=1
Force ASPM: Enable the pcie_aspm=force Kernel command-line option
In KDE, go to “System Settings” | “Desktop Effects” | “Advanced” and set the “Scale method” to “Crisp”.

Overall, this brings my T420s’s power consumption down below 9 W. For best results, use a recent Linux 3.1-rc pre-release.

Current NVIDIA Drivers for Ubuntu Natty

Thilo-Alexander Ginkel — Sun, 31 Jul 2011 20:18:51 +0000

If you are looking for current NVIDIA drivers for Ubuntu Natty (11.04), my new PPA may be of interest to you. It hosts an Ubuntu port of the current release version 275.21 of the NVIDIA Linux driver.

To install:

sudo apt-add-repository \ ppa:thilo.ginkel/nvidia-graphics-drivers sudo apt-get update sudo apt-get upgrade

Caution: There are some reports on the nvnews.net forums that this driver version breaks Gnome / GTK applications under certain circumstances, which I can neither confirm nor deny as I am using KDE (but GTK apps work correctly for me). You have been warned, use at your own risk.

Bug relief

Thilo-Alexander Ginkel — Mon, 25 Apr 2011 23:29:30 +0000

Just in case you have also been bitten by KDE bug 261323 (chances are good if you are running KDE on a multi-core system with an nVidia graphics card and compositing enabled) and are using Kubuntu (Maverick): You can get updated KDE 4.6.2 packages, which include a fix for this issue by KDE developer Martin Gräßlin, from my PPA:

https://launchpad.net/~thilo.ginkel/+archive/kde-4.6.x

Upgrading Cassandra 0.6.x to 0.7.0

Thilo-Alexander Ginkel — Fri, 14 Jan 2011 00:46:01 +0000

Just a brief recap of what manual steps are needed to upgrade Cassandra from 0.6.x to 0.7.0 using Debian packages:

Convert /etc/cassandra/storage-config.xml to /etc/cassandra/cassandra.yaml using the config-converter script. This currently does not seem to be included in the 0.7.0 .debs, so just grab a binary distribution to get hold of the script.
chown -R cassandra.cassandra /var/lib/cassandra/
Start Cassandra (typically using /etc/init.d/cassandra start)
Fire up jconsole, connect to localhost:8080 (or whatever JMX port you chose instead) and execute org.apache.cassandra.db -> StorageService -> Operations -> loadSchemaFromYAML

Enjoy!

SCM-SCL011-Treiber (“nPA-Basisleser”) unter LGPL?

Thilo-Alexander Ginkel — Wed, 24 Nov 2010 20:14:38 +0000

Vor kurzem hatte ich mir einen SCL011-RFID-Reader bestellt. Nicht, weil ich mir den neuen Personalausweis zugelegt hätte – bewahre. Ich wollte vielmehr schon immer mal mit RFID herumexperimentieren. Und da es diesen Reader aktuell zum Preis einer Pizza vom Italiener gibt, habe ich zugeschlagen – viel falsch machen kann man bei dem Preis ja nicht.

Heute lag der Reader in der Post und als ich gerade den Linux-Treiber installieren wollte, dachte ich mir, ich schaue mir diesen vorab mal im Detail an. Und was sehen meine müden Augen da? In einem Descriptor (scl011_2.06_linux_64bit/proprietary/SCL011.bundle/Contents/Info.plist), der dem Treiber-Binary beigepackt ist, steht zur Lizenz:

This driver is protected by terms of the GNU Lesser General Public License version 2.1, or (at your option) any later version.

Ich habe beim Hersteller jedenfalls mal den passenden Quellcode angefordert und werde über die Reaktion hier berichten.

Skype under Kubuntu Lucid Lynx

Thilo-Alexander Ginkel — Mon, 31 May 2010 20:18:39 +0000

As Skype voice recording stopped working for me after upgrading from Karmic to Lucid, I thought I would document what I needed to do to fix it:

Apparently, PulseAudio had my microphone muted although KMixer did not show this. The mute could easily be removed using pavucontrol, though.

Ext4 Performance Improvements

Thilo-Alexander Ginkel — Tue, 24 Nov 2009 20:44:03 +0000

In order to speed up the general performance of my personal computer I put an Intel X25-M SSD into it some time ago and made sure that most binaries that are needed to start up Linux are loaded from the SSD. I could not go without a conventional hard disk, though, because the storage capacity of typical SSDs (or the budget that I am willing to spend) is still too limited. While boot times already improved dramatically after adding the SSD, mounting the file systems located on my conventional hard disk was still limiting the overall speed of the boot process.

That was when I read about the performance improvements introduced by the ext4 file system.

So, today I migrated my /var and /home file system from ext3 to ext4 (which explains my previous blog post) and the results are pretty stunning. Ext4 seems to have improved the time it takes to mount a clean file system by an order of magnitude. Combined with the SSD performance boost the overall startup now nearly feels like “instant on” and the kdm log-on screen shows up in under five seconds after Linux has started booting.

If there was just a way to speed up the BIOS POST procedure (which now actually takes longer than starting up the OS)…

Answers

Thilo-Alexander Ginkel — Wed, 21 Oct 2009 06:39:07 +0000

A picture is worth a thousand words

Firefox 3.5 on Ubuntu

Thilo-Alexander Ginkel — Sun, 05 Jul 2009 14:03:10 +0000

Being both a Firefox and (K)ubuntu user I was awaiting the Firefox 3.5 release last week only to find out that a branded Firefox 3.5 release will not be made available for Jaunty Jackalope (Ubuntu 9.04), but only for its successor release, Karmic Koala.

Instead, there are various “Shiretoko Browser” incarnations available for Jaunty, the artwork of which I do not consider very appealing.

Still, I wanted to use Firefox 3.5 due to the speed improvements it offers compared to its predecessor.

Well, Firefox is free open source software, so all I had to was to fetch its source code from the Ubuntu Mozilla Security Team PPA and change the branding. The result is available in yet another PPA I created. Detailed installation instructions are available on the PPA page.

The Answer Has Arrived: KDE 4.2 Has Been Released

Thilo-Alexander Ginkel — Thu, 29 Jan 2009 05:57:53 +0000

The (at least by me) long-awaited KDE 4.2 release has hit the road! What can I say: It’s beautiful and now contains most of the features that one wanted from a modern desktop environment that were still missing in KDE 4.1. I think I will write a more-detailed article about KDE 4.2 in a couple of days and so will concentrate today on a feature that many people were missing in previous 4.x releases: Icons on the desktop. Yes, there were some workarounds in 4.1.x like placing a large folder view plasmoid on the desktop, but nobody really liked it. In 4.2 the whole desktop becomes a large folder view at the user’s command just as one is used to from KDE 3.5 or Windows. To activate it, just right click on the new shiny desktop and select Appearance Settings from the context menu. Select “Folder View” from the “Type” drop-down and you are done.