KDE
Related articles
KDE is a software project currently comprising of a desktop environment known as Plasma (or Plasma Workspaces), a collection of libraries and frameworks (KDE Frameworks) and several applications (KDE Applications) as well. KDE upstream has a well maintained UserBase wiki. Detailed information about most KDE applications can be found there.
Contents
- 1 Installation
- 2 Starting Plasma
- 3 Configuration
- 4 System administration
- 5 Desktop search
- 6 PIM
- 7 Phonon
- 8 Useful applications
-
9 Tips and tricks
- 9.1 Using an alternative window manager
- 9.2 Integrate Android
- 9.3 Configure KWin to use OpenGL ES
- 9.4 Speed up application startup
- 9.5 Configuring monitor resolution / multiple monitors
- 9.6 Open application launcher with Super key (Windows key)
- 9.7 Enabling touchpad tap to click on plasma wayland session
-
10 Troubleshooting
- 10.1 Configuration related
- 10.2 Clean akonadi configuration to fix KMail
- 10.3 Fix empty IMAP inbox
- 10.4 Getting current state of KWin for support and debug purposes
- 10.5 KDE and Qt programs look bad when in a different window manager
- 10.6 KF5/Qt5 applications don't display icons in i3/fvwm/awesome
-
10.7 Graphical related problems
- 10.7.1 Plasma keeps crashing with legacy Nvidia
- 10.7.2 Applications don't refresh properly
- 10.7.3 Low 2D desktop performance (or) artifacts appear when on 2D
- 10.7.4 Low 3D desktop performance
- 10.7.5 Desktop compositing is disabled on my system with a modern Nvidia GPU
- 10.7.6 Flickering in fullscreen when compositing is enabled
- 10.7.7 Display settings lost on reboot (multiple monitors)
- 10.8 Sound problems under KDE
- 10.9 Inotify folder watch limit
- 10.10 Freezes when using Automount on a NFS volume
- 10.11 Locale warning when installing packages in Konsole
- 10.12 Multi-monitor issues
- 11 Unstable releases
- 12 Bugs
- 13 See also
Installation
Plasma Desktop
Before installing Plasma, make sure you have a working Xorg installation on your system.
Install the plasma-meta meta-package or the plasma group. For differences between plasma-meta and plasma reference Creating packages#Meta packages and groups. Alternatively, for a more minimal Plasma installation, install the plasma-desktop package.
Upgrading from Plasma 4 to 5
- Isolate
multi-user.target
:# systemctl isolate multi-user.target
- If you use KDM as display manager, disable the
kdm.service
systemd unit. - Uninstall the kdebase-workspaceAUR package.
- Install the plasma-meta package or the plasma group.
- Enable the
sddm.service
systemd unit, or install and enable any other display manager. - Reboot or simply start the systemd
sddm.service
unit.
KDE applications and language packs
To install the full set of KDE Applications, install the kde-applications group or the kde-applications-meta meta-package. Note that this will only install applications, it will not install any version of the Plasma Desktop.
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.
Starting Plasma
To launch a Plasma 5 session, choose Plasma in your display manager menu.
Alternatively, to start Plasma with startx, append exec startkde
to your .xinitrc
file. If you want to start Xorg at login, please see Start X at login.
Wayland
As of Plasma 5.8, Plasma on Wayland should be usable, although there are a few known problems.
- To start a Plasma on Wayland session from a display manager, install the plasma-wayland-session package and Plasma should show up in the display manager.
- To start a Plasma on Wayland session from a console, run
startplasmacompositor
.
Configuration
Most settings for KDE applications are stored in ~/.config
, but some older applications may use ~/.kde4
. However, configuring KDE is primarily done through the System Settings application. It can be started from a terminal by executing systemsettings5.
Frameworks 5 applications can use KDE 4 configuration however they expect the configuration files to be located in different places. To allow Frameworks 5 applications running in KDE 4 to share the same configurations they may be moved to the new locations and symlinked back to the old. Examples are:
- Konsole profiles from
~/.kde4/share/apps/konsole
to~/.local/share/konsole/
- Application appearance from
~/.kde4/share/config/kdeglobals
to~/.config/kdeglobals
Personalization
Plasma desktop
Themes
Plasma themes define the look of panels and plasmoids. For easy system-wide installation, some such themes are available in both the official repositories and the AUR.
The easiest way to install themes is by going through the Desktop Settings control panel:
Workspace Theme > Desktop Theme > Get new Themes
This will present a nice frontend for kde-look.org that allows you to install, uninstall, or update third-party plasmoid scripts with literally just one click.
Splash and Lock screens are currently unavailable so to customize these screens you have to modify the original theme found in /usr/share/plasma/look-and-feel/
.
See this thread on the Kubuntu forums.
Note that the SDDM login screen is not part of this theme.
Qt and GTK+ Applications Appearance
- Qt4
For Qt4 applications to have a consistent appearance, there are two options:
Install breeze-kde4 and then pick Breeze as GUI Style in qtconfig-qt4
; or install breeze-gtk and pick GTK+ as GUI Style.
- GTK+
The recommended theme for a pleasant appearance in GTK+ applications is breeze-gtk or gnome-breeze-gitAUR, a GTK+ theme designed to mimic the appearance of Plasma 5 Breeze. Install kde-gtk-config and select the installed GTK-theme for GTK2/GTK3-Theme in System Settings > Application Style > GNOME Application Style.
In some themes, tooltips in GTK+ applications have white text on white backgrounds making it difficult to read. To change the colors in GTK2 applications, find the section for tooltips in the gtkrc file and change it. For GTK3 application two files need to be changed, gtk.css and settings.ini.
Widgets
Plasmoids are little scripted (plasmoid scripts) or coded (plasmoid binaries) KDE applications designed to enhance the functionality of your desktop.
The easiest way to install plasmoid scripts is by right-clicking onto a panel or the desktop and choosing Add Widgets > Get new Widgets > Download Widgets. This will present a nice frontend for kde-look.org that allows you to install, uninstall, or update third-party plasmoid scripts with literally just one click.
Many Plasmoid binaries are available from the AUR.
Sound applet in the system tray
Install plasma-pa or kmix (start Kmix from the Application Launcher).
Disable panel shadow
As the plasma panel is on top of other windows, its shadow is drawn over them. [3] To disable this behaviour without impacting other shadows, install xorg-xprop and run:
$ xprop -remove _KDE_NET_WM_SHADOW
then select the panel with the plus-sized cursor. [4] For automation, install xorg-xwininfo and create the following script:
/usr/local/bin/kde-no-shadow
#!/bin/bash for WID in $(xwininfo -root -tree | sed '/"Plasma": ("plasmashell" "plasmashell")/!d; s/^ *\([^ ]*\) .*/\1/g'); do xprop -id $WID -remove _KDE_NET_WM_SHADOW done
The script can be run on login with Add Script in Autostart:
$ kcmshell5 autostart
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 in the AUR.
Icon themes
Icon themes can be installed and changed on System Settings > Icons.
Fonts
Fonts in a Plasma session 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 anything in System Settings > Fonts.
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 restart your desktop). Note that Gnome's Font Preferences also does this.
Fonts are huge or seem disproportional
Try to force font DPI to 96 in System Settings > Application Appearance > Fonts.
If that does not work, try setting the DPI directly in your Xorg configuration as documented here.
Space efficiency
The Plasma Netbook shell has been dropped from Plasma 5, see the following KDE forum post
However, you can achieve something similar by editing the file ~/.config/kwinrc
adding
BorderlessMaximizedWindows=true
in the [Windows]
section.
Printing
You can also configure printers in System Settings > Printer Configuration. To use this method, you must first install print-manager and cups.
The avahi-daemon.service
and org.cups.cupsd.service
daemons must be started first; otherwise, 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 your user the right to manage printers.
There was an error during CUPS operation: 'cups-authorization-canceled'
For CUPS, this is set in /etc/cups/cups-files.conf
.
Adding lpadmin
to /etc/group
and then to the SystemGroup
directive in /etc/cups/cups-files.conf
allows anyone in the lpadmin
group to configure printers. Do not add the lp
group to the SystemGroup
directive, or printing will fail.
# groupadd -g107 lpadmin
/etc/cups/cups-files.conf
# Administrator user group... SystemGroup sys root lpadmin
Samba/Windows support
If you want to have access to Windows services, install Samba (package samba).
The Dolphin share functionality requires the package kdenetwork-filesharing and usershares, which the stock smb.conf does not have enabled. Instructions to add them are in Samba#Creating usershare path, after which sharing in Dolphin should work out of the box after restarting Samba.
KDE Desktop activities
KDE Desktop Activities are Plasma-based virtual-desktop-like sets of Plasma Widgets where you can independently configure widgets as if you have more than one screen or desktop.
On your desktop, click the Cashew Plasmoid and, on the pop-up window, press "Activities".
A plasma bar presenting you the current existing Plasma Desktop Activities will appear at the bottom of the screen. You can navigate between them by pressing the correspondent icons.
Power saving
Plasma 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).
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 kdirwatchAUR[broken link: archived in aur-mirror] from AUR which is a GUI frontend for kdirwatch.
Autostarting applications
Plasma can autostart applications and run scripts on startup and shutdown. To autostart an application, start systemsettings
and navigate to Startup and Shutdown -> Autostart and add the program or shell script of your choice. For applications, a .desktop
file will be created, for shell scripts, a symlink will be created.
Place Desktop entries (i.e. .desktop
files) here:
~/.config/autostart
- for starting applications at login.
Place or symlink shell scripts in one of the following directories:
~/.config/plasma-workspace/env
- for executing scripts at login before launching Plasma.
~/.config/autostart-scripts
- for executing scripts at login.
~/.config/plasma-workspace/shutdown
- for executing scripts on shutdown.
System administration
Terminate Xorg server through KDE System Settings
Navigate to the submenu System Settings > Input Devices > Keyboard > Advanced (tab) > "Key Sequence to kill the X server" and ensure that the checkbox is ticked.
KCM
KCM stands for KConfig Module. KCMs can help you configure your system by providing interfaces in System Settings, or through the command line with kcmshell5.
Configuration for look and feel of GTK applications.
- kde-gtk-config
- kcm-gtkAUR[broken link: archived in aur-mirror]
- kcm-qt-graphicssystemAUR
Configuration for the GRUB bootloader.
- grub2-editorAUR[broken link: archived in aur-mirror]
Configuration for the Uncomplicated Firewall (UFW)
- kcm-ufwAUR
Configuration for PolicyKit
Configuration for Wacom tablets
Configuration for systemd
More KCMs can be found at kde-apps.org.
Desktop search
KDE implements desktop search with a software called Baloo, a file indexing and searching solution.
Baloo
Using and configuring Baloo
In order to search using Baloo on the KDE Plasma Desktop, press ALT+F2
and type in your query. Within Dolphin press CTRL+F
.
By default the Desktop Search KCM exposes only two options: A panel to blacklist folders and a way to disable it with one click.
Alternatively you can edit your ~/.config/baloofilerc
file (info). Additionally the balooctl
process can also be used. In order to disable Baloo run balooctl disable
.
Once you added additional folders to the blacklist or disabled Baloo entirely, a process named baloo_file_cleaner
removes all unneeded index files automatically. They are stored under ~/.local/share/baloo/
.
More advanced configuration options are available through kcm_baloo_advancedAUR[broken link: archived in aur-mirror].
How do I index a removable device?
By default every removable device is blacklisted. You just have to remove your device from the blacklist in the KCM panel.
Web browsers
Konqueror and Rekonq
Konqueror supports two rendering engines – KHTML and QtWebKit (via the kwebkitpart package) – Rekonq supports only QtWebKit. KHTML development was halted after Qt shipped WebKit but was kept for compatibility reasons. QtWebKit, in turn, has since been deprecated by the Qt Project and replaced by Chromium-based Qt WebEngine which is currently not supported by either Konqueror or Rekonq. There is a community continuation of QtWebKit.
A successor named Fiber is currently in development, which will use Chromium's engine.
Chromium and Chrome
Chromium and its proprietary variant Google Chrome have limited Plasma integration. They can use KWallet and KDE Open/Save windows.
Firefox
Firefox can be configured to better integrate with Plasma. See Firefox KDE integration for details.
Qupzilla
Qupzilla (qupzilla) is a Qt web browser with Plasma integration features. Qupzilla 2.0 uses Qt WebEngine intead of WebKit. The WebKit variant is also available as qupzilla-qtwebkit-gitAUR.
PIM
KDE offers its own stack for personal information management. This includes emails, contacts, calendar, etc.
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.
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).
Installation
Install akonadi. For additional addons, install kdepim-addons. For EWS support, install akonadi-ews-gitAUR.
Disabling Akonadi
See this section in the KDE userbase.
Database configuration
MariaDB/MySQL
Using ZFS
If your home directory is on a ZFS pool, you will need to create ~/.config/akonadi/mysql-local.conf
with the following contents:
[mysqld] innodb_use_native_aio = 0
Otherwise you will get the OS error 22
PostgreSQL
- Install and setup PostgreSQL (see PostgreSQL)
- Enable the
postgresql
systemd service:systemctl enable postgresql.service
.
- Enable the
- Create the
~/.config/akonadi/akonadiserverrc
file if it does not exist. - Edit
~/.config/akonadi/akonadiserverrc
file so that it has the following contents:[General] Driver=QPSQL [QPSQL] Host=/run/postgresql/ InitDbPath=/usr/bin/initdb Name=akonadi Options= Password= Port=5432 ServerPath=/usr/bin/pg_ctl StartServer=true User=postgres
- Start Akonadi:
akonadictl start
, and check its status:akonadictl status
.
SQLite
Edit ~/.config/akonadi/akonadiserverrc
to match the configuration below:
[General] Driver=QSQLITE3 [QSQLITE3] Name=/home/username/.local/akonadi/akonadi.db
Phonon
From Wikipedia:
- “Phonon is the multimedia API provided by KDE and is the standard abstraction for handling multimedia streams within KDE software and also used by several Qt applications.
Phonon was originally created to allow KDE and Qt software to be independent of any single multimedia framework such as GStreamer or xine and to provide a stable API for a major version's lifetime.”
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 backends based on GStreamer and VLC – each available in versions for Qt4 applications and Qt5 applications (phonon-qt4-gstreamer, phonon-qt5-gstreamer – phonon-qt4-vlc, phonon-qt5-vlc).
Upstream prefers VLC but prominent Linux distributions (Kubuntu and Fedora-KDE for example) prefer GStreamer because that allows them to easily leave out patented MPEG codecs from the default installation. Both backends have a slightly different features set.
In the past other backends were developed as well but are no longer maintained and their AUR packages have been deleted.
Useful applications
The official set of KDE applications may be found here.
Yakuake
Yakuake provides a Quake-like terminal emulator whose visibility is toggled by the F12 key. It also has support for multiple tabs. Yakuake is available in the 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 telepathy-kde-meta package that includes all the packages contained in the telepathy-kde group.
Use Telegram with KDE Telepathy
Telegram protocol is available using telepathy-haze, installing telegram-purpleAUR or telegram-purple-gitAUR and telepathy-morse-gitAUR. The username is the Telegram account telephone number (complete with the national prefix '+xx', e.g. '+49' for Germany). The configuration through the GUI may be tricky: if the phone number is not accepted when configuring a new account in the KDE Telepathy client (with an error message complaining about an invalid parameter which prevents the account creation), insert it between single quotes and then remove the quotes manually from the configuration file (~/.local/share/telepathy/mission-control/accounts.cfg
) after the account creation (if the quotes are not removed after, an authentication error should rise). Note that the configuration file should be edited manually when KDE Telepathy is not running, e.g. when there is no KDE desktop session active, otherwise manual changes may be overwritten by the software.
Tips and tricks
Using an alternative window manager
There may be reasons you want to use another window manager than KWin, for example to work around the DRI bug that causes black screen with PRIME.
To use an alternative window manager with Plasma open the System Settings panel, navigate to (Default) Applications > Window Manager > Use a different window manager and select the window manager you wish to use from the list.
KDE/Openbox session
The openbox package provides a session for using KDE with Openbox. To make use of this session, select KDE/Openbox from the display manager menu.
For those starting the session manually, add the following line to your .xinitrc
file:
exec openbox-kde-session
Compiz custom
If you need to run Compiz with custom options and switches select Compiz custom and then create a script called compiz-kde-launcher
and add to it the commands you wish to use to start Compiz. See the example below:
/usr/local/bin/compiz-kde-launcher
#!/bin/bash LIBGL_ALWAYS_INDIRECT=1 compiz --replace & wait
Then make it executable:
$ chmod +x /usr/local/bin/compiz-kde-launcher
Re-enabling compositing effects
When replacing Kwin with a window manager which does not provide a Compositor (such as Openbox), any desktop compositing effects e.g. transparency will be lost. In this case, install and run a separate Composite manager to provide the effects such as Xcompmgr or Compton.
Integrate Android
KDE Connect provides several features for you:
- Share files and URLs to/from KDE from/to any app, without wires.
- Touchpad emulation: Use your phone screen as your computer's touchpad.
- Notifications sync (4.3+): Read your Android notifications from the desktop.
- Shared clipboard: copy and paste between your phone and your computer.
- Multimedia remote control: Use your phone as a remote for Linux media players.
- WiFi connection: no usb wire or bluetooth needed.
- RSA Encryption: your information is safe.
You will need to install KDE Connect both on your computer and on your Android. For PC side, install kdeconnect package. For Android side, install KDE Connect
from Google Play or from F-Droid.
Configure KWin to use OpenGL ES
Set environment variable KWIN_COMPOSE
to 'O2ES' to force the OpenGL ES backend. Please note that OpenGL ES is not supported by all drivers.
Speed up application startup
User Rob described a "magic trick" on his blog to improve application start-up time by 50-150ms. To enable it, create this folder in your home:
$ mkdir ~/.compose-cache/
It can produce freezes under heavy io. To avoid this, also do:
$ ln -sfv /run/user/$UID/ /home/$USER/.compose-cache
Configuring monitor resolution / multiple monitors
To enable display resolution management and multiple monitors in Plasma 5, install kscreen. This adds the additional options to System Settings/Display and Monitor.
Open application launcher with Super key (Windows key)
Install and start ksuperkey. Now assign Alt+F1
as hot key. The Super
key will now open the application launcher. You can add ksuperkey to the autostart if you don't want to start it manually.
Enabling touchpad tap to click on plasma wayland session
Currently, it's not possible to configure tap to click via systemsettings on plasma wayland session. A workaround is provided to configure tap to click on plasma wayland session via dbus.
Here are simplified steps to get touchpad tap to click enabled on plasma wayland session.
Identify on which libinput recognizes the touchpad device.
# libinput-list-devices
Device: ETPS/2 Elantech Touchpad Kernel: /dev/input/event14 Group: 7 Seat: seat0, default Size: 78.28x38.78mm Capabilities: pointer Tap-to-click: disabled Tap-and-drag: enabled Tap drag lock: disabled Left-handed: disabled Nat.scrolling: disabled Middle emulation: n/a Calibration: n/a Scroll methods: *two-finger edge Click methods: none Disable-w-typing: enabled Accel profiles: none Rotation: n/a
In this case, the touchpad is identified as event14
Check whether KDE Dbus recognizes the touchpad. Replace event14
with the touchpad identifier found from libinput-list-devices
.
$ qdbus org.kde.KWin.InputDevice /org/kde/KWin/InputDevice/event14 org.freedesktop.DBus.Properties.Get org.kde.KWin.InputDevice name
ETPS/2 Elantech Touchpad
Check the current value of tapToClick
.
$ qdbus org.kde.KWin.InputDevice /org/kde/KWin/InputDevice/event14 org.freedesktop.DBus.Properties.Get org.kde.KWin.InputDevice tapToClick
false
Now set the tapToClick
value to true
.
$ qdbus org.kde.KWin.InputDevice /org/kde/KWin/InputDevice/event14 org.freedesktop.DBus.Properties.Set org.kde.KWin.InputDevice tapToClick true
Confirm that tapToClick
value is true
.
$ qdbus org.kde.KWin.InputDevice /org/kde/KWin/InputDevice/event14 org.freedesktop.DBus.Properties.Get org.kde.KWin.InputDevice tapToClick
true
After these steps performed, tap to click should work as expected.
Troubleshooting
Many problems in KDE are related to configuration.
Plasma desktop behaves strangely
Plasma problems are usually caused by unstable Plasma widgets (colloquially called plasmoids) or Plasma themes. First, find which was the last widget or 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, it is recommended you find the entry on kde-look.org and inform the developer of that widget about the problem (detailing steps to reproduce, etc).
If you cannot find the problem, but you do not want all the settings to be lost, navigate to ~/.config
:
$ for j in plasma*; do mv -- "$j" "${j%}.bak"; done
This command will rename all Plasma related configs to *.bak (e.g. plasmarc.bak
) of your user and when you will relogin into Plasma, you will have the default settings back. To undo that action, remove the .bak file extension. If you already have *.bak files, rename, move, or delete them first. It is highly recommended that you create regular backups anyway. See Synchronization and backup programs for a list of possible solutions.
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 music. 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.
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 System Settings 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.
Fix empty IMAP inbox
For some IMAP accounts, kmail will show the inbox as a container with all other folders of this account inside. Kmail does not show messages in the inbox container but in all other subfolders [7]. To solve this problem simply disable the server side subscribition in the kmail account settings.
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 on Martin's blog.
$ qdbus org.kde.KWin /KWin supportInformation
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 Plasma session (specifically, you did not run startkde
), then as of Plasma 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-qt4
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/qt4/pluginlib32-libdbusmenu-glibs/styles
Under Gnome you can try to install the package libgnomeui.
KF5/Qt5 applications don't display icons in i3/fvwm/awesome
See Qt#Configuration of Qt5 apps under environments other than KDE.
Plasma keeps crashing with legacy Nvidia
This is caused by a bug in Plasma when using the Nvidia-304xx driver. Rather than disabling compositing, create a file kwin.sh
in ~/.config/plasma-workspace/env/
with the following contents:
#!/bin/sh export KWIN_EXPLICIT_SYNC=0
Then go to system-settings > Startup and Shutdown > Autostart and Check/Add the script as a pre-KDE startup file.
Applications don't refresh properly
If you use 3D-accelerated composition with Intel, you might find that the Plasma panel and other applications don't refresh properly (stay frozen). Some Intel drivers have problems with EGL. Go to System Settings under Display and Monitor -> Compositor. Set OpenGL interface to OpenGL 3.1. If that does not work, see Intel graphics#SNA issues for alternative solutions.
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, your driver may 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-graphicssystemAUR 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 and 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 Sytem Settings > Desktop Effect > Advanced > Suspend desktop effects for fullscreen windows. Uncheck it would tell kwin to disable unredirect fullscren.
Display settings lost on reboot (multiple monitors)
There is a bug in kscreen that makes it forget dual screen settings after reboot with certain displays. A possible workaround is to uninstall kscreen and specify your screen setup in a xorg.conf file instead:
- See Multihead#RandR for using the RandR X Window System extension.
- For Nouveau you can use the template at Nouveau#Dual Head, just edit it to suit your setup.
- For the proprietary nvidia driver you can use the nvidia-settings utility as root to write the config file.
Sound problems under KDE
"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.
MP3 files cannot be played when using the GStreamer Phonon backend
This can be solved by installing the GStreamer libav plugin (package gst-libav). If you still encounter problems, you can try changing the Phonon backend used by installing another such as phonon-qt4-vlc or phonon-qt5-vlc. Then, make sure the backend is preferred via System Settings > Multimedia > Phonon > Backend (tab).
Inotify folder watch limit
If you get the following error:
KDE Baloo Filewatch service reached the inotify folder watch limit. File changes may be ignored.
Then you will need to increase the inotify folder watch limit:
# echo 10000 > /proc/sys/fs/inotify/max_user_watches
To make changes permanent, create /etc/sysctl.d/90-inotify.conf
with
#increase inotify watch limit fs.inotify.max_user_watches = 10000
Freezes when using Automount on a NFS volume
Using Fstab#Automount with systemd on a NFS volume may cause freezes, see bug report upstream.
Locale warning when installing packages in Konsole
mandb: can't set the locale; make sure $lc_* and $lang are correct
By default, Konsole sets $LANG to en_US.US-ASCII. If you haven't generated that locale, then mandb can't use it. In your Konsole profile settings, click "Environment" and then add a line for LANG=en_US.UTF-8 or whatever your locale should be.
Multi-monitor issues
The current release of KDE Plasma has several issues with multi-monitor setups, which can make Plasma unusable. See KDE Bug 356225.
These bugs have been resolved in the upstream/git KDE Plasma builds, which can be installed from plasma-desktop-gitAUR or plasma-git-metaAUR - bear in mind that all packages will conflict with current versions - it is recommended to remove them first.
Unstable releases
See Official repositories#kde-unstable
Bugs
It is preferable 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 are clear about what you want to report.
If you have any problem 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.