Difference between revisions of "KDE"

Revision as of 03:37, 5 October 2013

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From KDE Software Compilation and Getting KDE Software:

The KDE Software Compilation is the set of frameworks, workspaces, and applications produced by KDE to create a beautiful, functional and free desktop computing environment for Linux and similar operating systems. It consists of a large number of individual applications and a desktop workspace as a shell to run these applications.

The KDE upstream has a well maintained UserBase wiki. Users can get detailed information about most KDE applications there.

Installation

KDE 4.x is modular. You can install an entire set of packages or only install your preferred KDE applications.

Full install

Install kde or kde-meta available in the official repositories. For differences between kde and kde-meta see the KDE Packages article.

Minimal install

If you want to have a minimal installation of the KDE SC, install:

• kdebase
• phonon-vlc or phonon-gstreamer as phonon backend

Language pack

If you need language files, install kde-l10n-yourlanguagehere (e.g. kde-l10n-de for the German language).

For a full list of available languages see this link.

Upgrading

KDE 4.11 Software Compilation is the current major release of KDE. Important hints for upgraders:

• Always check if your mirror is up to date.
• Do not force an update using pacman --force. 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.

Starting KDE

Starting KDE depends on your preferences. Basically there are two ways of starting KDE. Using KDM or xinitrc.

Using a Display Manager

It is highly recommended to get familiar with the full article concerning display managers, before you make any changes.

KDM (KDE Display Manager)

See also KDM Wiki page.

Enable/start kdm.service.

Using xinitrc

The meaning and usage of xinitrc is very well described here.

kdebase-workspace provides startkde. Make sure it is installed. Then edit ~/.xinitrc, uncomment:

exec startkde

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

Configuration

All KDE configuration is saved in the ~/.kde4 folder. If your KDE is giving you a lot of trouble or if you ever want a fresh installation of KDE, just back this folder up and restart your X session. KDE will re-create this folder with all the default config files. If you want very fine-grained control over your KDE programs, then you may want to edit the files in this folder.

However, configuring KDE is primarily done in 'System Settings'. There are also a few other options available for the desktop with 'Default 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.

Personalization

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

Plasma desktop

Plasma is a desktop integration 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 and AUR.

Widgets

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

Plasmoid binaries must be installed using PKGBUILDS from AUR. Or write your own PKGBUILD.

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.

Most plasmoids are not created officially by KDE developers. You can also try installing Mac OS X widgets, Microsoft Windows Vista/7 widgets, Google Widgets, and even SuperKaramba widgets.

Sound applet in the system tray

Install Kmix (kdemultimedia-kmix) from the official repositories and start it from the application launcher. Since KDE autostarts programs from the previous session, the program need not be started manually every time one logs in.

Adding a Global Menu to the desktop

Install appmenu-qt from the official repos and appmenu-gtk^AUR, gtk3-appmenu^AUR, gtk2-appmenu^AUR, libdbusmenu^AUR, libdbusmenu-gtk2^AUR, libdbusmenu-gtk3^AUR and appmenu-qt5^AUR from the AUR in order to complete the preliminaries for an always-on globalmenu (mac-style). To get firefox and libreoffice support as well, install firefox-extension-globalmenu^AUR and libreoffice-extension-menubar^AUR from the AUR.

To actually get the globalmenu, install kdeplasma-applets-menubar^AUR from the AUR. Create a plasma-panel on top of your screen and add the window menubar applet to the panel. To export the menus to your globalmenu, go to System Settings > Application Appearance > Style. Now click the fine-tuning tab and use the drop-down list to select only export as your menubar style.

Window decorations

Window decorations can be changed in

System Settings > Workspace Appearance > Window Decorations

There you can also directly download and install more themes with one click and some are available on AUR.

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.

Official logos, icons, CD labels and other artwork for Arch Linux are provided in the archlinux-artwork package. After installing you can find such artwork at /usr/share/archlinux/.

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.

Space efficiency

Users with small screens (eg Netbooks) can change some setting to make KDE more space efficient. See upstream wiki for more info. Also you can use KDE's Plasma Netbook which is a workspace made specifically for small, lightweight netbook devices.

Networking

You can choose from the following tools:

• NetworkManager. See NetworkManager for more information.
• Wicd and its KDE front end wicd-kde^AUR. See Wicd for more information.

Printing

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 kdeutils-print-manager and cups.

You need to start the avahi-daemon and cupsd daemons 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, you need to give the user rights to manage printers:

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

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 instead of lp.

/etc/cups/cupsd.conf

# Administrator user group...
SystemGroup sys root lp

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

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.

On your desktop, click the Cashew Plasmoid and on the pop-up window 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.

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).

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. Arch uses ondemand as default CPU Frequency governor from kernel vesion 3.3. So nothing need to be done for most cases. For detaild fine tune of the governor, please see CPU Frequency Scaling.

Monitoring changes on local files and directories

KDE now uses inotify directly from the kernel with kdirwatch (included in kdelibs), so Gamin or FAM are no longer needed. You may want to install this kdirwatch^AUR from AUR which is a GUI frontend for kdirwatch.

System administration

Set keyboard

In order to do that, navigate to

   System Settings > Hardware > Input Devices > Keyboard

There you may choose your keyboard model at first.

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.

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.

Useful KCM

KCM means KConfig Module. This modules help you to configure you system providing a interface on System Settings.

Configuration for look&feel of your GTK apps.

• kde-gtk-config
• kcm-gtk^AUR
• kcm-qt-graphicssystem^AUR

Configuration for the GRUB2 bootloader.

• grub2-editor^AUR
• kcm-grub2^AUR

Configuration for Synaptics driver based touchpads.

• synaptiks
• kcm_touchpad^AUR

Configuration for UFW

• kcm-ufw^AUR

Configuration for PolicyKit

• kcm-polkit-kde-git^AUR

Configuration for Wacom Tablet

• kcm-wacomtablet^AUR

More KCM can be found here.

Desktop search and semantic desktop

According to Wikipedia, "the Semantic Desktop is a collective term for ideas related to changing a computer's user interface and data handling capabilities so that data is more easily shared between different applications or tasks and so that data that once could not be automatically processed by a computer can be (automatically processed)."

The KDE implementation of this concept is tied to (as of KDE 4.10) two major pieces of software, Akonadi and Nepomuk. Between the two of them, these programs look at your data and make an easily searchable index of it. The idea behind these pieces of software is to make your system "aware" of your data and give it context using meta-data and user-supplied tags.

Soprano and Virtuoso are two dependencies of the Nepomuk Semantic Desktop. Since the relationship between the two major components and their dependencies is not very clear, the following sections try to shed some light on their inner workings.

Virtuoso and Soprano

The database used to store all the metadata used by the semantic desktop is a Resource Description Framework (RDF) database called Virtuoso. Internally, Virtuoso may be looked as a relational database. (A relational database is different from a traditional single-table based database in the sense that it uses multiple tables related by a single key in order to store data.) It is currently controlled by OpenLink, and is available under commercial and an open source license.

From the KDE Techbase, Soprano is a Qt abstraction over databases. It provides a friendly Qt-based API for accessing different RDF stores. It currently supports 3 database backends - Sesame, Redland and Virtuoso. The KDE Semantic Stack only works with Virtuoso. Soprano also provides additional features such as serializing, parsing RDF data, and a client server architecture that is heavily used in Nepomuk.

Nepomuk

Nepomuk stands for "Networked Environment for Personal, Ontology-based Management of Unified Knowledge". It is what allows all the tagging and labeling of files as well to take place and also serves as the way to actually read the Virtuoso databases. It provides an API to application developers which allows them to read the data collected by it.

In the past, the "Strigi" service was used to collect data about the various files present on the system. However, due to many reasons, the most important of them being CPU and Memory usage, Strigi was replaced by a homegrown indexing service which is integrated with Nepomuk-Core.

For further information about Nepomuk, this page is a good resource. However, some of the information in the previous page has been rendered outdated according to this blog post.

Using and configuring Nepomuk

In order to search using Nepouk on the KDE desktop, press ALT+F2 and type in your query. Nepomuk is enabled by default. It can be turned on and off in

System Settings > Desktop Search

Nepomuk has to keep track of a lot of files. It is for this reason that it is recommended to increase the number of files that can be watched with inotify. In order to do that this command is a good option.

sysctl fs.inotify.max_user_watches=524288

To do it persistently:

echo "fs.inotify.max_user_watches = 524288" >> /etc/sysctl.d/99-inotify.conf

Restart Nepomuk to see the changes.

KDE without Nepomuk

If you wish to run KDE without Nepomuk, there exists a nepomuk-core-fake^AUR package in the AUR.

Akonadi

Akonadi is a system meant to act as a local cache for PIM data, regardless of its origin, which can be then used by other applications. This includes the user's emails, contacts, calendars, events, journals, alarms, notes, and so on. It interfaces with the Nepomuk libraries to provide searching capabilities.

Akonadi does not store any data by itself: the storage format depends on the nature of the data (for example, contacts may be stored in vcard format).

For more information on Akonadi and its relationship with Nepomuk, see [1] and [2].

Disabling Akonadi

See this section in the KDE userbase.

Database configuration

Start akonaditray from package kdepim-runtime. Right click on it and select configure. In the Akonadi server configure tab, you can:

• Configuring Akonadi to use MySQL Server running on the System
• Configuring Akonadi to use sqlite

Running KDE without Akonadi

The package akonadi-fake^AUR is a good option for those who wish to run KDE without Akonadi.

Phonon

What is Phonon?

From Wikipedia: 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.

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).

Which backend should I choose?

You can choose between various backends, like GStreamer (phonon-gstreamer) or VLC (phonon-vlc) available in the official repositories, Xine (phonon-xine^AUR) or MPlayer (phonon-mplayer-git^AUR) available on AUR. 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.

According to announcement of KDE 4.6 in Arch and mail in Phonon dev list, users should prefer GStreamer over VLC due to the feature difference.

Useful applications

The official set of KDE applications may be found here.

Yakuake

This application provides a Quake-like terminal emulator, which is toggled visible using the F12 key. It also has support for multiple tabs. Yakuake can be installed by package yakuake.

KDE Telepathy

KDE Telepathy is a project with the goal to closely integrate Instant Messaging with the KDE desktop. It utilizes the Telepathy framework as a backend, and is intended to replace Kopete.

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 .

Tips and tricks

Configure KWin to use OpenGL ES

Beginning with KWin version 4.8 it is possible to use the separately built binary kwin_gles as a replacement for kwin. It behaves almost the same as the kwin executable in OpenGL2 mode with the slight difference that it uses egl instead of glx as the native platform interface. To test kwin_gles you just have to run kwin_gles --replace in Konsole. If you want to make this change permanent you have to create a script in $(kde4-config --localprefix)/env/ which exports KDEWM=kwin_gles.

Enabling audio thumbnails under Konqueror/Dolphin file managers

For thumbnails of audio files in Konqueror and Dolphin install audiothumbs^AUR from AUR.

Enabling video thumbnails under Konqueror/Dolphin file managers

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

Speed up application startup

User Rob wrote on his blog this "magic trick" to improve applications start up by 50-150ms. To enable it, create this folder in your home:

$ mkdir -p ~/.compose-cache

For those curious about what is going on here, this enables an optimization which Lubos (of general KDE speediness fame) came up with some time ago and was then rewritten and integrated into libx11. Ordinarily on startup applications read input method information from /usr/share/X11/locale/<your locale>/Compose. This Compose file is quite long (>5000 lines for the en_US.UTF-8 one) and takes some time to process. libX11 can create a cache of the parsed information which is much quicker to read subsequently, but it will only re-use an existing cache or create a new one in ~/.compose-cache if the directory already exists. [Cit. Rob]

Hiding partitions

In Dolphin, it is as simple as right-clicking on the partition in the 'Places' sidebar and selecting 'Hide <partition>'. Otherwise...

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:

KERNEL=="sda1", ENV{UDISKS_IGNORE}="1"
KERNEL=="sda2", ENV{UDISKS_IGNORE}="1"

Konqueror tips

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]
Enabled=false

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.

Using WebKit

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

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 WebKit as the Default web browser engine.

Firefox integration

See Firefox#KDE_integration.

Setting the screensaver background to the same as the current one

For the beauty of a system you can placed your current background for your Kscreensaver instead of the default.

KDE is by default not able to changes this for the 'Simple Lock', see in this[1] open bug for more Info.

But there is a a small workaround for this[2][3].

Change into the /usr/share/apps/ksmserver/screenlocker/org.kde.passworddialog/contents/ui/ directory and edit the main.qml with your editor of your choice.

Create a backup of this file,

cp main.qml main.qml.baku

then edit on the line 45 and replace:

- source: theme.wallpaperPathForSize(parent.width, parent.height)
+ source: "1920x1080.jpg"

Now you copy your current background image to "1920x1080.jpg".

Note you have to redo this for each update of the package kdebase-workspace.

Links:

[1] https://bugs.kde.org/show_bug.cgi?id=312828

[2] http://lists.opensuse.org/opensuse-kde/2013-02/msg00082.html

[3] http://forum.kde.org/viewtopic.php?f=66&t=110039

Setting lockscreen wallpaper to arbitrary image

Copy an existing wallpaper profile as a template:

cd .kde4/share/wallpapers/
cp -r /usr/share/wallpapers/ExistingWallpaper .

Change the name in the directory, and edit the .desktop file:

mv ExistingWallpaper MyWallpaper
vim MyWallpaper/metadata.desktop

[Desktop Entry]
Name=MyWallpaper
X-KDE-PluginInfo-Name=MyWallpaper

Remove existing images:

rm MyWallpaper/contents/screenshot.png
rm MyWallpaper/contents/images/*

Copy new image in:

cp MyWallpaper.png MyWallpaper/contents/images/1920x1080.png

Edit the metadata profile for the current theme:

cp .kde4/share/apps/desktoptheme/MyTheme/metadata.desktop metadata.desktop.orig
vim .kde4/share/apps/desktoptheme/MyTheme/metadata.desktop

[Wallpaper]
defaultWallpaperTheme=NewWallpaper
defaultFileSuffix=.png
defaultWidth=1920
defaultHeight=1080

Lock the screen to check that it worked.

Troubleshooting

Configuration related

Many issues in KDE are related to configuration. One way to resolve upgrade problems is to start over with a fresh KDE config.

Reset all KDE configuration

To test whether your config is the problem try quitting your KDE session by logging out and, in a tty, run

$ mv ~/.kde4 ~/.kde4.safekeeping
$ rm .kde4/{cache,socket,tmp}-$(hostname)

The rm command just removes symbolic links which will be recreated by KDE automatically. Now start a new KDE session to see the results.

If the problem is resolved, you will have a fresh, problem-free ~/.kde4. You can gradually move parts of your saved configuration back, restarting your session regularly to test, to identify the problematic parts of your config. Some files here are named after applications so you will probably be able to test these without needing to restart KDE.

File Indexer Service not working even after enabling everything properly

This is caused due to a corrupted Nepomuk database. It may be remedied by moving the database or deleting it all together. Log out of KDE and issue this command from a virtual console:

$ mv ~/.kde4/share/apps/nepomuk ~/.kde4/share/apps/nepomuk_backup

to move your existing (and corrupt) nepomuk database. It will be recreated when you log in again.

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.

Clean cache to resolve upgrade problems

The problem may be caused by old cache. Sometimes after an upgrade, the old cache might introduce strange, hard to debug behaviour such as unkillable shells, hangs when changing various settings and several other problems such as ark being unable to unrar or unzip or amarok not recognizing any of your musics. This solution can also resolve problems with KDE and QT programmes looking bad following upgrade.

Rebuild your cache with the following commands:

 $ rm ~/.config/Trolltech.conf
 $ kbuildsycoca4 --noincremental

Hopefully, your problems are now fixed.

Reference.

Clean akonadi configuration to fix kmail

First, make sure that KMail is not running. Then backup configuration:

$ mv ~/.local/share/akonadi  ~/.local/share/akonadi-old
$ mv ~/.config/akonadi ~/.config/akonadi-old

Start SystemSettings -> Personal and remove all the resources. Go back to Dolphin and remove the original ~/.local/share/akonadi and ~/.config/akonadi - the copies you made ensure that you can back-track if necessary.

Now go back to the SystemSettings page and carefully add the necessary resources. You should see the resource reading in your mail folders. Then start Kontact/KMail to see if it work properly.

Getting current state of KWin for support and debug purposes

This command prints out a wonderful summary of the current state of KWin including used options, used compositing backend and relevant OpenGL driver capabilities. See more at Martin's blog

qdbus org.kde.kwin /KWin supportInformation

KDE4 does not finish loading

There might be a situation in which the graphic driver might create a conflict when starting KDE4. This situation happens after the login but before finishing loading the desktop, making the user wait indefinitely at the loading screen. Until now the only users confirmed to be affected by this are the ones that use Nvidia drivers and KDE4.

A solution for Nvidia users is to edit the file at /home/user/.kde4/share/config/kwinrc and change the option Enabled=true to false in the [Compositing] section. For more information look at this thread.

If a minimal install was done, make sure you installed the required font by your phonon backend listed here: KDE#Minimal_install

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

Under Gnome you can try to install the package libgnomeui.

Graphical related issues

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, NVIDIA, Intel for more information, in order to make sure that everything is all right. The open-source ATI and Intel drivers and the proprietary (binary) Nvidia driver 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 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, and Native is just using the X11 rendering (mixture, usually).

The best and automatic way to do that is to install kcm-qt-graphicssystem^AUR from AUR and configure this particular Qt setting through

 System Settings > Qt Graphics System

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

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.

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.

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 fullscren.

Screen Tearing with desktop compositing enabled

KWin may suffer from screen tearing while desktop effects are enabled. Uncheck the VSync option under System Settings > Desktop Effects > Advanced > "Use Vsync".

For proprietary driver users, ensure that the driver's VSync option is enabled (amdccle for Catalyst users, and nvidia-settings for Nvidia users).

Sound problems under KDE

ALSA related problems

"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 (package gstreamer0.10-plugins. If you still encounter problems, you can try changing the Phonon backend used by installing another such as phonon-vlc. Then make sure the backend is preferred via:

 System Settings > Multimedia > Phonon > Backend (tab)

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
[[ "${PROMPT_COMMAND}" ]] && PROMPT_COMMAND="$PROMPT_COMMAND;history -a" || PROMPT_COMMAND="history -a"

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

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.

Desktop does not respond for several seconds at startup

There is a bug in either pulseaudio or kde that makes the desktop not being usable for a few seconds after it has showed up (for example if you click on the K-menu it does not appears until that waiting time has elapsed).

The workaround is to disable /etc/xdg/autostart/pulseaudio.desktop by adding the following line at the end (do not omit the semicolon):

NotShowIn=KDE;

Note that you could also remove that file, or renaming it (to pulseaudio.desktop.disable or the like) but then it will not load in other Desktop Managers, and will be restored by a package update.

Reference.

Dolphin and File Dialogs are extremely slow to start everytime

May be caused by the upower service. If the upower service is not needed on your system, it can be disabled :

  systemctl disable upower
  systemctl mask upower

Obviously this will not have any side effect on a desktop system.

Default PDF viewer in GTK applications under KDE

In some cases when you have installed Inkscape, Gimp or other graphic programs, GTK applications (Firefox among all) might not select Okular as the default PDF application, and they are not going to follow the KDE settings on default applications. You can use the following user command to make Okular the default application again.

xdg-mime default kde4-okularApplication_pdf.desktop application/pdf

If you are using a different PDF viewer application, or a different mime-type is misbehaving, you should change kde4-okularApplication_pdf.desktop and application/pdf respectively according to your needs.

For more information, consult Default Applications wiki page.

Problems following updates to KDE packages

If you reboot to problems following a system update involving KDE packages, try rebooting a second time. For some reason, problems often magically resolve themselves following a second reboot.

Other KDE projects

Official kde-unstable

When KDE is reaching beta or RC milestone, KDE "unstable" packages are uploaded to the [kde-unstable] repo. They stay there until KDE is declared stable and passes to [extra].

You may add it by adding:

[kde-unstable]
SigLevel = PackageRequired
Include = /etc/pacman.d/mirrorlist

to /etc/pacman.conf

1. kde-unstable is based upon testing. Therefore, you need to enable the repositories in the following order: kde-unstable, testing, core, extra, community-testing, community.
2. To update from a previous KDE installation, run: pacman -Syu or pacman -S kde-unstable/kde
3. If you don't have KDE installed, you might have difficulties to install it by using groups (limitation of pacman)
4. Subscribe and read the arch-dev-public mailing list
5. Make sure you make bug reports if you find any issues.

Trinity

From the release of KDE 4.x, the developers dropped support for KDE 3.5.x. Trinity Desktop Environment is a fork of KDE3 developed by Timothy Pearson (trinitydesktop.org). This project aims to keep the KDE3.5 computing style alive, as well as polish off any rough edges that were present as of KDE 3.5.10. See Trinity for more info.

Bugs

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

If you have any issue and you write about in on the Arch forums, first make sure that you have FULLY updated your system using a good sync mirror (check here) or try Reflector.

See also

• KDE Homepage
• KDE Bug Tracker
• Arch Linux Bug Tracker
• KDE WebSVN