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For users on GNU/Linux and Unix, KDE offers a full suite of user workspace applications which allow interaction with these operating systems in a modern, graphical user interface. This article covers its installation, configuration, and troubleshooting.
KDE uses the Qt toolkit.
The Xorg project provides a free software implementation of the X Window System – the foundation for a graphical user interface. Desktop environments such as LXQt, Openbox/KDE, Cinnamon, MATE, Xfce, GNOME, Deepin provide a complete graphical environment. Various window managers offer alternative and novel environments, and may be used standalone to conserve system resources. Display managers provide a graphical login prompt.
KDevelop 4

From KDE - KDE Software Compilation:

The KDE Software Compilation grew out of the history of the KDE Project. In its inception, KDE was formed to create a beautiful, functional and free desktop computing environment for GNU/Linux and similar operating system. At the time, these systems lacked a graphical user environment that could rival the offerings from the larger proprietary operating system vendors. KDE was created to fill this gap.
The KDE Software Compilation is the set of libraries, workspaces, and applications produced by KDE that share this common heritage, and continue to use the synchronized release cycle. Software may move in and out of this semi-formally defined collection depending on the particular needs of the contributors who are working on that software, with exceptions made to ensure that binary compatibility remains at the library level throughout any major release of the compilation.

From KDE - Getting KDE Software:

KDE software consists of a large number of individual applications and a desktop workspace as a shell to run these applications. You can run KDE applications just fine on any desktop environment. KDE applications are built to integrate well with your system's components. By using also KDE workspace, you get even better integration of your applications with the working environment while lowering system resource needs.


1 Overview

KDE 4.8 Software Compilation is the current major release of KDE that includes a number of improvements and bug fixes. The new Parabola package set for KDE makes it possible to only install those applications you like.

Important features of the Parbola KDE SC in short:

  • Split packages; for more Information see KDE Packages and Splitting KDE.
  • You can use different Phonon backends, like Gstreamer or VLC
  • Meta packages ensure a smooth upgrade and emulate the old monolith packages for those who prefer them.

Important hints for upgraders:

  • Always check if your mirror is up to date.
  • pacman will ask you to replace all kde packages with kde-meta packages.
  • Do not force an update. If pacman complains about conflicts please file a bug report.
  • You can remove the meta packages and the sub packages you do not need after the update.
  • If you do not like split packages just keep using the kde-meta packages.

Information about upstream changes is available here

2 Installation

KDE 5.x is modular. You can install an entire set of packages or only install your preferred KDE applications. See KDE Packages for more information.

Note: If you do not have Xorg installed on your system, be sure to install it beforehand, or include it in the process of installing KDE

2.1 Full install

There are were two packages to choose from: kde and kde-meta (no longer). Learn about their difference in the KDE Packages article.

To install the entire KDE set, first fully upgrade your system:

# pacman -Syu --noconfirm

Install kde or kde-meta available in the Official Repositories. If you need language files, install kde-l10n-yourlanguagehere e.g. kde-l10n-de for the German language.

2.2 Minimal install

If you want to have a minimal installation of the KDE SC but also session for Openbox window manager, here is an example:

# pacman -S --noconfirm plasma openbox obconf-qt

You can choose phonon-gstreamer instead of phonon-vlc.

Note: You need to install a ttf-* package. phonon-vlc already requires ttf-freefonts, but when using phonon-gstreamer you should add ttf-dejavu or another too.

3 Starting KDE

Starting KDE depends on your preferences. Basically there are two ways of starting KDE. Using either


  • xinitrc.

3.1 Using SDDM, a Simple desktop display manager

It is highly recommended to get familiar with this full article concerning display managers, before you make any changes. See also SDDM Wiki page.

3.1.1 I - Starting SDDM through /etc/inittab
Note: This option used to be recommended earlier, but in 2016 is outdated. systemd is the current method at hand. Also install systemd kcmshell package for handy configuration from within system settings via GUI.

Edit /etc/inittab and comment out:



#x:5:respawn:/usr/bin/sddm -nodaemon

Then uncomment:



x:5:respawn:/usr/bin/sddm -nodaemon
3.1.2 II - Starting SDDM thru OpenRC
# sddm --example-config > /etc/sddm.conf
# nano /etc/conf.d/xdm
# rc-udpate add xdm default
3.1.3 III - Starting SDDM through systemd

(Recommended in 2016+ installations) If you are using systemd init instead of outdated /etc/inittab, then you must enable the service related to KDM as follows:

# systemctl enable kdm.service

Then reboot.

3.1.4 IV - Starting SDDM as a daemon

Add sddm to daemons array in /etc/rc.conf:

DAEMONS=(metalog dbus network crond ... sddm)

Note: In all methods KDM starts at boot and loads Xorg automatically. Apply only 1 of the 3 alternatives above, not any 2 or more. Otherwise, your /var/log/messages.log will be littered with this message: init: Id "x" respawning too fast: disabled for 5 minutes The daemon method may not be applicable either, so one is really left with the option #2 = systemd and its kcm only.

3.2 Using the .xinitrc run command file

For usage of .xinitrc see also: Xinitrc. kdebase-workspace provided startkde (while it was in the repo). Make sure it is installed regardless of it missing in the repo.

Note: Alternatively, consider Plasma instead of kdebase-workspace. This is the way to go in 2016 and later

Then edit ~/.xinitrc, uncomment (if Openbox is also installed):

exec ck-launch-session openbox-kde-session

After a reboot or/and login, each execution of Xorg (startx or xinit) will start KDE automatically.

Warning: By doing this you might possibly disable the restart/shutdown function in the KDE menu.

If you want to start Xorg at boot, see also Start X at boot.

4 Configuration

Note: Configuring KDE is primarily done in 'System Settings', once you actually get there from here. There are also a few other options available for the desktop with 'Desktop Settings' when you right click the desktop.

For other personalization options not covered below such as activities, different wallpapers on one cube, etc please refer to the Plasma wiki page.

4.1 Personalization

How to set up the KDE desktop to your personal style; use different Plasma themes, window decorations and icon themes.

4.1.1 Plasma Workspaces

Plasma is a desktop technology that provides many functions from displaying the wallpaper, adding widgets to the desktop, and handling the panels or "taskbar". Themes

Plasma themes can be installed through the Desktop Settings control panel. Plasma themes define how your panels and plasmoids look like. If you like to have them installed system-wide, themes can be found in both the official repositories. Plasmoid widgets

Plasmoids / widgets are little scripted or coded KDE apps that enhance the functionality of your desktop. There are two kinds, plasmoid scripts and plasmoid binaries.

The easiest way to install plasmoid scripts is by right-clicking onto a panel or the desktop:

Add Widgets -> Get new Widgets -> Download Widgets

This will present a nice frontend for kde-look.org and allows you to (un)install or update third-party plasmoid scripts with just one click.

Note: Most plasmoids are not created officially by KDE developers.

4.1.2 Window Decorations

Window decorations can be changed in

System Settings -> Workspace Appearance -> Window Decorations

4.1.3 KDE 4 Theme Integration with GTK Applications

Please go to Uniform Look for QT and GTK Applications.

4.1.4 Icon Themes

Not many full system icons themes are available for KDE 4. You can open up System Settings > Application Appearance > Icons and browse for new ones or install them manually. Many of them can be found on kde-look.org.

4.1.5 Fonts Fonts in KDE look poor

Try installing the ttf-dejavu and ttf-liberation packages.

After the installation, be sure to log out and back in. You should not have to modify any settings in the "Fonts" panel of the KDE System Settings application.

If you have personally set up how your Fonts render, be aware that System Settings may alter their appearance. When you go System Settings > Appearance > Fonts System Settings will likely alter your font configuration file (fonts.conf).

There is no way to prevent this but if you set the values to match your fonts.conf file the expected font rendering will return (it will require you to restart your application or in a few cases for you to have to restart your desktop).

Note too that Gnomes' Font Preferences will also do this if you use both desktop environments. Fonts are huge or seems disproportional

Try to force fonts DPI to 96 on System Settings > Application Appearance > Fonts.

If it does not work try set DPI directly on Xorg configuration here.

4.1.6 Screen space efficiency

KDE is often criticized for being bloated.

The user might get this perception from seeing many toolbars and pretty big scaled icons wasting many pixels in the applications. One thing that improved the situation was the new Kwin-Theme that came with KDE SC 4.4.* with the more elegant buttons that one can also resize. KDE Apps allows to hide many toolbars, menubars and statusbars. All sorts of *bars

Most toolbars of a program can be removed in the menubar-entry "Settings". There you often can hide the statusbar and often all toolbars. The last step should be to remove the menubar itself via Ctrl + M.

If you do not want to remove any bars you can still make them smaller or remove the text via:

System Settings -> Application Appearance -> Style -> Fine Tuning ->  (Main toolbar text / Secondary toolbar text)

Since most aspect ratios of modern flat screens are wider than 4:3 it could be reasonable to put the toolbar at the left or right of a window to artificially stretch windows more to the monitors aspect ratio. Plasma

There are also some settings and modifications you can apply to your plasmoid (-widgets) (use them via "add widgets" right click while on desktop) to make KDE less space wasting.

For example, the "Digital Clock" wastes more space than the "Analogue Clock". The little plasma icon (formerly "Cashew") that one can see in the panel can be hidden by locking the widgets via rightclicking onto the panel.

If you have got many tasks in your task-manager you should consider using Icon Tasks.

This alternative task-manager allows you to just display the icons of a task thus using less space but still maintaining the ability of the user to distinguish the different tasks.

Since KDE 4.8, the old smoothtask plasmoid is in the kdeplasma-addons group, for use it, install the kdeplasma-addons-applets-icontasks package.

After installing and substituting it with the original task-manager you should have a deep look at the settings since they are much broader. One way of using the features of Icon Tasks could be to only display the icons of tasks and move the panel to the left or right of the screen. This is most useful on widescreens.

On very small screens it could be reasonable to set the bottom-panel to auto-hide completely.

For netbooks there is a special workspace, called Plasma Netbook, that makes better use of the screen:

System Settings -> Workspace Behavior -> Workspace -> Workspace Type KWin

Windows decorations can also be resized by decreasing button size in the decoration thus making the whole top border smaller:

System Settings -> Workspace Appearance -> Window Decorations -> Configure Decoration... -> Button size

You could also remove the side-border of all windows via:

System Settings -> Workspace Appearance -> Window Decorations -> Configure Decoration... -> Border size Kicker / KMenu

Menu Titles - To disable the menu titles in kmenu, just add the entry ShowMenuTitles=false to the [menus] section of ~/.kde4/share/config/kickerrc.

Note: You reach this function faster via the GUI (rightclick in menu icon) or by running kmenuedit explicitely

Menu Icon Size - To adjust the size of the icons in kmenu, just add the entry MenuEntryHeight=X to the [menus] section of ~/.kde4/share/config/kickerrc, where X is one of the available icon sizes of your theme (16,24,32 etc)

Two Rows Of Icons In The Systray - Just set your kicker height to 48 pixels manually. This is the smallest size where you still get two rows of icons in the systray.

4.2 Networking

NetworkManager support has been added in KDE a while ago. See NetworkManager for more information.

4.3 Printing

Tip: Use the Cups web interface for faster configuration.

The printers are configured in this way can be found in applications KDE.

You can also choose the printer configuration through System Settings -> Printer Configuration. To use this method, you must first install the packages kdeadmin-system-config-printer-kde and cups.

You need to start the cupsd daemon first or you will get the following error:

The service 'Printer Configuration' does not provide an interface 'KCModule' 
with keyword 'system-config- printer-kde/system-config-printer-kde.py' 
The factory does not support creating components of the specified type.

If you are getting the following error:

There was an error during CUPS operation: 'cups-authorization-canceled'

This means you need to give the user rights to manage printers.

For CUPS, this is set in /etc/cups/cupsd.conf.

Adding lp to SystemGroup allows anyone who can print to configure printers. You can, of course, add another group than lp.

# Administrator user group...
SystemGroup sys root lp

4.4 Samba/Windows support

If you want to have access to Windows services install Samba (package samba).

You may then configure your Samba shares through

 System Settings -> Sharing -> Samba

4.5 KDE Desktop "Activities"

KDE Desktop "Activities" are Plasma based "virtual desktop"-like set of Plasma Widgets where you can independently configure widgets as if you had more than one screens/desktops. In other words, one can have multiple independent screens where to put a wallpaper, launcher-icons, window-list asf..

On your desktop, click the "Cashew" Plasmoid (denoted "Standard" activity) and on the pop-up dialogue press "Activities".

A plasma bar will appear at the bottom of the screen which presents you the current Plasma Desktop Activities which exist. You can then navigate between them by pressing their correspondent icon.

4.6 Power Saving

KDE has an integrated power saving service called "Powerdevil Power Management" that may adjust the power saving profile of the system and/or the brightness of the screen (if supported).

4.6.1 How to enable Cpufreq based power saving

Since KDE 4.6, CPU frequency scaling is no longer managed by KDE. Instead it is assumed to be handled automatically by the the hardware and/or kernel. While some distributions use the ondemand cpufreq governor by default, Arch does not.

As a prerequisite to the following, you should carefully read through the wiki article on cpufreq and ensure that the appropriate kernel modules are loaded. If you are happy with setting your governor once at boot (with the cpufreq daemon script, for example) then this section is not relevant and can be skipped.

1. If you have not already done so, install the cpufrequtils package (for the cpufreq-set utility).

2. Next, you will need to grant access to cpufreq-set for the appropriate users by configuring sudo. For example, if you are part of the wheel group, you could use visudo to add

%wheel ALL = (ALL) NOPASSWD: /usr/bin/cpufreq-set

to your sudoers file.

In visudo usually use R ... replace # with SPACE ... then ESC :wq (write out and quit)

3. From System Settings > Power Management > Power Profiles select a profile to edit or create a new one. Check the Run Script option and add an appropriate cpufreq-set command for the selected power profile. For example, your "Powersave" profile might have:

sudo cpufreq-set -r -g ondemand

Your "Performance" profile might have

sudo cpufreq-set -r -g performance
Note: The cpufreq-set examples above may be insufficient for setting the governor for all processors/cores.

For some CPU families the -r switch may not set the governor for all cores/cpus and instead only set the governor for CPU 0. In this case you will need to write a script to iterate through all your cores. A simple script for a four core system could look like:

for i in {0..3}; do
  sudo /usr/bin/cpufreq-set -c${i} -gondemand
Note: You can check which governors are active with cpufreq-info -o or less intuitively by inspecting /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor.

5 System Administration

5.1 Set keyboard layout in order switch language inputs

In order to do that, navigate to

   System Settings > Hardware > Input Devices > Keyboard

There you may choose your keyboard model at first.

Note: It is preferable that, if you use Evdev, that means Xorg automatic configuration for keyboards, you should choose "Evdev-managed keyboard".

In the "Layouts" tab, you choose the languages you may want to use by pressing the "Add Layout" button and therefore the variant and the language. In the "Advanced" tab, you can choose the keyboard combination you want in order to change the layouts in the "Key(s) to change layout" sub-menu.

5.2 Terminate Xorg-server through KDE system settings

Navigate to

   System Settings -> Input Devices -> Keyboard -> Advanced (tab) > "Key Sequence to kill the X server" submenu

and tick the checkbox. Usually CTRL-SHIFT-BACKSPACE.

6 Desktop Search and Semantic Desktop

Most users who freshly install KDE are wondering what functionality the following four pieces of software are able to offer. Most features are still somehow hidden under the hood and yet not many applications featured in the KDE SC are using these interfaces. This chapter intends to first explain the features and then convince the user of the power these tools offer once properly integrated into KDE. The following sections are more or less a roughly shortened version of this blogpost.

6.1 Soprano

Soprano is a library for QT that is able to process RDF data. This is semantic data. Semantic data is a special kind of metadata which is much more flexible than metadata you might know from MP3-Tags or Meta-Tags in HTML since RDF data more resembles the structure of a spoken sentence, thus allowing a much wider field of ways dealing with them. Soprano stores semantic data in a backend and allows low level access to this data.

6.2 Nepomuk

Nepomuk is somehow the glue between Soprano and the KDE Desktop and thus the user. Nepomuk allows to tag the files with various entries and offers an API for the applications featured in KDE SC. It is enabled by default. Nepomuk can be turned on and off in

System Settings -> Desktop Search

Nepomuk has to keep the trace of a lot of files, because of that is recommended to increase the number of files that can be watched with inotify, to do that:

sysctl fs.inotify.max_user_watches=524288

To do it persistant:

echo "fs.inotify.max_user_watches = 524288" >> /etc/sysctl.conf

And restart Nepomuk.

6.3 Akonadi

Akonadi is one of the ways of getting data into Nepomuk. Its intention is to gather all kinds of PIM data from KMail, KAdressbook or Kopete. It collects chat contacts, email addresses, email attachments and email contents. First of all it feeds Nepomuk with this data but moreover it provides a centralized access point for all this data.

6.3.1 Disabling Akonadi

If you do not want Akonadi to be ran in your system (for your own reasons), edit ~/.config/akonadi/akonadiserverrc and turn




And then relogin into your account.

6.3.2 Configuring Akonadi to use MySQL Server running on the System

First, you need to set up the database using the following commands (replace password with the correct one):

 GRANT ALL PRIVILEGES ON akonadi.* TO 'akonadiuser' IDENTIFIED BY 'password';

If ~/.config/akonadi/mysql-local.conf does not exist then

cp /usr/share/config/akonadi/mysql-global.conf ~/.config/akonadi/mysql-local.conf

and uncomment the following line


Then edit ~/.config/akonadi/akonadiserverrc:




Restart the Akonadi server with:

akonadictl restart

6.3.3 Configuring Akonadi to use sqlite

According to the kdepim FAQ, sqlite doesn't work too well under load, but according to several users, it gives much better performance than the alternatives.

First stop Akonadi:

akonadictl stop

Change the Driver-line in ~/.config/akonadi/akonadiserverrc to the following:


Then start Akonadi again:

akonadictl start

6.4 Strigi Search

Strigi is another way of feeding data into Nepomuk. It preferably indexes the users home-folder. Indexing means that it not only gathers filenames but also information about your music collection or tagged downloads you did with Kget. The Strigi search is also integrated into KDEs launcher which can be accessed via: Alt + F2

By default, Dolphin has a search bar on top-right where you may type what you want to be found from Strigi's index.

Note: Strigi has implications for resource usage on your computer - CPU, memory, disk access, disk space, battery life. If Strigi is too resource-hungry for you, you can turn it off in "System Settings -> Desktop Search".

Strigi folder indexing can be configured in:

System Settings -> Desktop Search -> Desktop Query -> Customize index folders…

7 Phonon

7.1 What is Phonon?

Phonon is the multimedia API for KDE 4. Phonon was created to allow KDE 4 to be independent of any single multimedia framework such as GStreamer or xine and to provide a stable API for KDE 4's lifetime. It was done for various reasons: to create a simple KDE/Qt style multimedia API, to better support native multimedia frameworks on Windows and Mac OS X, and to fix problems of frameworks becoming unmaintained or having API or ABI instability.

from Wikipedia.

Phonon is being widely used within KDE, for both audio (e.g., the System notifications or KDE audio apps) and video (e.g., the Dolphin video thumbnails).

7.2 Which backend should I choose?

You can choose between various backends, like GStreamer (phonon-gstreamer) phonon-gstreamer, VLC (phonon-vlc) phonon-vlc, Xine in [unsupported] (phonon-xine) or even MPlayer in [unsupported] (phonon-mplayer). Most users will want GStreamer or VLC which have the best upstream support. Note that multiple backends can be installed at once and you can switch between them via System Settings -> Multimedia -> Phonon -> Backend.

8 Using WebKit in Konqueror

WebKit is an open source browser engine developed by Apple Inc. It is a derivative from the KHTML and KJS libraries and contain many improvements. WebKit is used by Safari, Google Chrome and rekonq.

8.1 How to use in Konqueror

It is possible to use WebKit in Konqueror instead of KHTML. First install the kwebkitpart package :

 pacman -S kwebkitpart

Then, after executing Konqueror, press Settings > Configure Konqueror.

On the "General" submenu, select the "WebKit" as the "Default web browser engine".

9 Icecat/Iceweasel integration

See Icecat.

10 Useful Application

10.1 Telepathy

A new project, known as Real-Time Communication and Collaboration, has been started in KDE. The goal is to integrate Instant Messaging clients with the desktop systems.

At the moment things are in progress and miss some features, but a very base communication system is ready.

To install all Telepathy protocols install the telepathy group. To use the KDE Telepathy client, install the kde-telepathy-meta package that includes all the packages contained in the kde-telepathy group .

11 Tips and tricks

11.1 Configure KWin to use OpenGL ES

Starting with kdebase-workspace 4.8 kwin offers the possibility to use the OpenGL ES 2.0 backend for displaying a composited desktop. In some cases the OpenGL ES backend is faster than the standard OpenGL backend. If you want kwin to use the OpenGL ES backend you have to create the following file:

[Desktop Entry]
Name=KWin GLES

After you have created the file you can change the windows manager in the system settings. Open System Settings, go to Default Applications, Window Manager, select Use a different window manager: and select KWin GLES.

11.2 Enabling thumbnails under Konqueror and Dolphin file managers

For thumbnails of videos in konqueror and dolphin install kdemultimedia-mplayerthumbs or kdemultimedia-ffmpegthumbs.

11.3 Hiding partitions

If you wish to prevent your internal partitions from appearing in your file manager, you can create an udev rule, for example /etc/udev/rules.d/10-local.rules:

KERNEL=="sda[0-9]", ENV{UDISKS_IGNORE}="1"

The same thing for a certain partition:


11.4 Konqueror Tips

11.4.1 Disabling Smart Key Tooltips (Browser)

To disable those smart key tooltips in Konqueror (pressing CTRL on a web page), open ~/.kde4/share/config/konquerorrc and add this section:

[Access Keys]

11.4.2 Disabling The Sidebar Tab (Filemanager)

To disable this small sidebar tab on the left side, open ~/.kde4/share/config/konqsidebartng.rc and set HideTabs to true.

11.4.3 Using WebKit

WebKit is a free software browser engine developed by Apple Inc. It is a derivative from the KHTML and KJS libraries and contain many improvements.

It is possible to use WebKit in Konqueror instead of KHTML. First install the kwebkitpart package.

Then, after executing Konqueror, press Settings > Configure Konqueror.

On the "General" submenu, select the "WebKit" as the "Default web browser engine".

12 Troubleshooting

12.1 KDE and Qt programs look bad when in a different window manager

If you are using KDE or Qt programs but not in a full KDE session (specifically, you did not run "startkde"), then as of KDE 4.6.1 you will need to tell Qt how to find KDE's styles (Oxygen, QtCurve etc.)

You just need to set the environment variable QT_PLUGIN_PATH. E.g. put

export QT_PLUGIN_PATH=$HOME/.kde4/lib/kde4/plugins/:/usr/lib/kde4/plugins/

into your /etc/profile (or ~/.profile if you do not have root access). qtconfig should then be able to find your kde styles and everything should look nice again!

Alternatively, you can symlink the Qt styles directory to the KDE styles one:

# ln -s /usr/lib/kde4/plugins/styles/ /usr/lib/qt/plugins/styles

12.2 KHotkeys issue

Ιf khotkeys does not work, make sure you have a fully updated system first. You can also create ~/.kde4/Autostart/reloadkhotkeys.sh with contents

(sleep 3 && qdbus org.kde.kded /modules/khotkeys reread_configuration) &

and then do a

chmod -R 0755 ~/.kde4/Autostart/reloadkhotkeys.sh

then logout & login.

12.3 Suspend to Disk/Ram not working

If you are starting KDE with startx try adding ck-launch-session to the .xinitrc, as so:

# ~/.xinitrc
# Executed by startx (run your window manager from here)
# exec startlxqt
exec ck-launch-session openbox-kde-session
# exec mate-session
# exec startxfce4
# ...or the window manager that you’ve chosen

This is done automatically with SDDM.

12.4 Graphical related issues

12.4.1 Low 2D desktop performance (or) Artifacts appear when on 2D GPU driver problem

Make sure you have the proper driver for your card installed, so that your desktop is at least 2D accelerated. Follow these articles for more information: ATI, Nouveau, Intel for more information, in order to make sure that everything is all right. The free software ATI, Intel and Nouveau drivers should theoretically provide the best 2D and 3D acceleration. The Raster engine workaround

If this does not solve your problems, maybe your driver does not provide a good XRender acceleration which the current Qt painter engine relies on by default.

You can change the painter engine to software based only by invoking the application with the "-graphicssystem raster" command line. This rendering engine can be set as the default one by recompiling Qt with the same as configure option, "-graphicssystem raster".

The raster paint engine enables the CPU to do the majority of the painting, as opposed to the GPU. You may get better performance, depending on your system. This is basically a work-around for the terrible GNU/Linux driver stack, since the CPU should obviously not be doing graphical computations since it is designed for fewer threads of greater complexity, as opposed to the GPU which is many threads but lesser computational strength. So, only use Raster engine if you are having problems or your GPU is much slower than you CPU, otherwise is better to use XRender.

Since Qt 4.7+, recompiling Qt is not needed. Simply export QT_GRAPHICSSYSTEM=raster, or "opengl", or "native" (for the default). Raster depends on the CPU, OpenGL depends on the GPU and high driver support (it is buggy and highly in development, so I would not expect it to work), and Native is just using the X11 rendering (mixture, usually).

 System Settings > Qt Graphics System

For more information, consult this KDE Developer blog entry and/or this Qt Developer blog entry.

12.4.2 Konsole is slow in applications like vim

This is a problem that is caused by slow glyph rendering. You can solve this by switching to a scalable font like Bitstreamkwebkitpart Vera Sans Mono.

12.4.3 Low 3D desktop performance

KDE begins with desktop effects enabled. Older cards may be insufficient for 3D desktop acceleration. You can disable desktop effects in

System Settings -> Desktop Effects

or you can toggle desktop effects with Alt + Shift + F12

12.4.4 Desktop compositing is disabled on my system with a modern Nvidia GPU

Sometimes, KWin may have settings in its configuration file (kwinrc) that may cause a problem on re-activating the 3D desktop OpenGL compositing. That could be caused randomly (for example, due to a sudden Xorg crash or restart, and it gets corrupted), so, in case that happens, delete your ~/.kde4/share/config/kwinrc file and relogin. The KWin settings will turn to the KDE default ones and the problem should be probably gone.

12.4.5 Flickering in fullscreen when compositing is enabled

As of KDE SC 4.6.0, there is an option in systemsettings -> Desktop Effect -> Advanced -> "Suspend desktop effects for fullscreen windows" Uncheck it would tell kwin to disable unredirect fullscreen.

12.5 Sound problems under KDE

12.5.1 ALSA related problems

Note: First make sure you have alsa-lib and alsa-utils installed. "Falling back to default" messages when trying to listen to any sound in KDE

When you encounter such messages:

The audio playback device <name-of-the-sound-device> does not work.
Falling back to default

Go to

System Settings -> Multimedia -> Phonon

and set the device named "default" above all the other devices in each box you see. I cannot play mp3 files when using the GStreamer Phonon backend

That can be solved by installing the GStreamer plugins:

 pacman -S gstreamer0.10-bad-libre
 pacman -S gstreamer0.10-bad-libre-plugins
 pacman -S gstreamer0.10-base-plugins
 pacman -S gstreamer0.10-ffmpeg
 pacman -S gstreamer0.10-good-plugins
 pacman -S gstreamer0.10-ugly-plugins

If you still encounter problems, you can try changing the Phonon backend used by installing another such as phonon-vlc:

 pacman -S phonon-vlc

Then make sure the backend is perfered via:

 System Settings -> Multimedia -> Phonon -> Backend (tab)

12.6 Parabola specific packaging issues

Due to some upgrades on the packages or a newer versioned pacman with bugs (pft, like there are any ;) there could be some problems during upgrading. Please read the sections below, if you have a problem.

12.7 I wanted a minimal installation of KDE. After I installed some packages and logged in KDE, there are no panels

If you wanted a minimal installation of KDE, logged in, heard the login sound but nothing else happened, you may not have installed the Plasma binaries which are included in plasma-workspace and plasma-meta. Install them and restart Xorg.

12.8 I want a fresh installation of KDE for my system. What should I do?

Just rename the settings directory of KDE (just in case you will want to go back to your original settings):

mv ~/.kde4 ~/.kde4-backup

12.9 Plasma desktop behaves strangely

Plasma issues are usually caused by unstable plasmoids or plasma themes. First, find which was the last plasmoid or plasma theme you had installed and disable it or uninstall it.

So, if your desktop suddenly exhibits "locking up", this is likely caused by a faulty installed widget. If you cannot remember which widget you installed before the problem began(sometimes it can be an irregular problem), try to track it down by removing each widget until the problem ceases. Then you can uninstall the widget, and file a bug report (bugs.kde.org) only if it is an official widget. If it is not, I recommend you find the entry on kde-look.org and inform the developer of that widget about the issue (detailing steps to reproduce, etc).

If you cannot find the problem, but you do not want all the KDE settings to be lost, do:

 rm -r ~/.kde4/share/config/plasma*

This command will delete all plasma related configs of your user and when you will relogin into KDE, you will have the default settings back. You should know that this action cannot be undone. You ought to create a backup folder and copy all the plasma related configs in it.

12.10 Konsole does not save commands' history

By default console commands' history is saved only when you type 'exit' in console. When you close Konsole with 'x' in the corner it does not happen. To enable autosaving after every command execution you should add following lines into your .bashrc

shopt -s histappend

12.11 KDE password prompts display three bullets per char

You can change it under System Settings > Account Details. At Password & User Account the options are:

  • Show one bullet for each letter
  • Show three bullets for each letter
  • Show nothing

12.12 knotify4 process constantly uses CPU time

It is a bug with Gstreamer phonon back-end. Try changing to VLC phonon on System Settings > Multimedia > Phonon > Backend. If this is not in the list, install it (package phonon-vlc).

If you do not want change the back-end you can try use an external player to play the sound systems. First install mplayer, vlc or any other sound player.

Go to System Settings > Application and System Notifications > Manage Notifications > Player Settings and change to Use an external player putting the path of your preferred sound player.

12.13 Nepomukserver process still autostart even with semantic desktop disabled

Go to System Settings > Startup and Shutdown > Service Manager > Startup Services and uncheck the Nepomuk Search Module.

13 Bugs

13.1 Distro and Upstream bug report

It is preferrable that if you find a minor or serious bug, you should visit the Parabola Bug Tracker or/and KDE Bug Tracker in order to report that. Make sure that you be clear on what you want to report.

KDE 4 config files are usually located at


and for app-specific configs


14 External Links

15 Acknowledgement

This wiki article is based on ArchWiki. We may have removed non-FSDG bits from it.