KDE
Related articles
KDE is a software project currently comprising of a desktop environment known as Plasma, 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 Applications
- 5 Tips and tricks
-
6 Troubleshooting
- 6.1 Configuration related
- 6.2 Clean akonadi configuration to fix KMail
- 6.3 Fix empty IMAP inbox
- 6.4 Getting current state of KWin for support and debug purposes
- 6.5 KF5/Qt5 applications do not display icons in i3/fvwm/awesome
- 6.6 Graphical related problems
- 6.7 Sound problems under KDE
- 6.8 Inotify folder watch limit
- 6.9 Freezes when using Automount on a NFS volume
- 6.10 No Suspend/Hibernate options
- 6.11 Problems with saving credentials and persistently occuring KWallet dialogs
- 7 See also
Installation
Plasma
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.
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 Plasma.
Most KDE packages ship their own translations. The exception is KDE4-based packages from kde-applications. If you need language files for these packages, install kde-l10n-yourlanguagehere
(e.g. kde-l10n-de for the German language). For a full list of available languages see the kde-l10n split package.
Unstable releases
See Official repositories#kde-unstable
Starting Plasma
Plasma can be started either graphically, using a display manager, or manually from the console.
Graphically
To launch a Plasma session, choose Plasma in your display manager menu.
As of Plasma 5.9, Plasma on Wayland should be usable, up to Qt 5.7. With Qt 5.8, it is broken (fix upcoming in Qt 5.9). Also see the Plasma 5.9 Errata. 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.
Manual
To start Plasma with xinit/startx, append exec startkde
to your .xinitrc
file. If you want to start Xorg at login, please see Start X at login. To start a Plasma on Wayland session from a console, run startplasmacompositor
. Note that qt5-wayland is required to run Plasma on Wayland.
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
.
Some Frameworks 5 applications can use KDElibs 4 configuration, after moving the configuration files to the new location. 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 System Settings > Workspace Theme > Desktop Theme > Get new Themes.
This will present a nice frontend for https://store.kde.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's Breeze theme. 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-2.0
file and change it. For GTK3 application two files need to be changed, gtk.css
and settings.ini
.
It might also help to uncheck the option to Apply colors to non-Qt applications under System Settings > Colors.
Some GTK2 programs like vuescan-binAUR still look hardly usable due to invisible checkboxes with the Breeze or Adwaita skin in a Plasma session. To workaround this, install and select e.g. the Numix-Frost-Light skin of the numix-frost-themesAUR under System Settings > Application Style > GNOME Application Style (GTK) > Select a GTK2 Theme:. Numix-Frost-Light looks similar to Breeze.
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 https://store.kde.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). plasma-pa is now installed by default with plasma, no further configuration needed.
Disable panel shadow
As the Plasma panel is on top of other windows, its shadow is drawn over them. [1] 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. [2] 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 > Application Style > 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 are using qt5ct, the settings in Qt5 Configuration Tool may override the font settings in System Settings.
If you have personally set up how your Fonts render, be aware that System Settings may alter their appearance. When you go System Settings > 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 > Fonts.
If that does not work, try setting the DPI directly in your Xorg configuration as documented in Xorg#Setting DPI manually.
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.
Thumbnail generation
To allow thumbnail generation for media or document files on the desktop and in Dolphin, install kdegraphics-thumbnailers, ffmpegthumbs and kde-thumbnailer-odfAUR.
Then enable the thumbnail categories for the desktop via right click on the desktop background > Configure Desktop > Icons > More Preview Options....
In Dolphin, navigate to Control > General > Previews.
Printing
You can also configure printers in System Settings > Printers. To use this method, you must first install print-manager and cups. See CUPS#Configuration.
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.
Plasma's abilities to access SMB shares are limited, though. Writing to Windows shares is problematic and opening files from such shares, e.g. large videos, makes Plasma copying the whole file to the local system first. To workaround this, you can install a GTK based file browser like thunar with gvfs and gvfs-smb (and gnome-keyring for saving login credentials) to access SMB shares in a more able way. Another possible workaround is to mount a Samba share via cifs-utils to make it look to Plasma like if the SMB share was just a normal local folder and thus can be accessed normally. The mount command could look like the following for write access to a public share:
# mount -t cifs -o username=*,password=*,uid=1000,gid=1000,file_mode=0660,dir_mode=0770 //networkhost/share/ /home/user/localmountpoint/
Make it permanent:
/etc/fstab
//networkhost/share/ /home/user/localmountpoint/ cifs defaults,username=*,password=*,uid=1000,gid=1000,file_mode=0660,dir_mode=0770 0 2
It migh or it might not be necessary to append .local
to the hostname.
KDE Desktop activities
KDE Desktop Activities are special workspaces where you can select specific settings for each activity that apply only when you are using said activity.
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).
Autostarting applications
Plasma can autostart applications and run scripts on startup and shutdown. To autostart an application, navigate to System Settings > 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.
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.
Applications
The KDE project provides a suite of applications that integrate with the Plasma desktop. See the kde-applications group for a full listing of the available applications. Also see Category:KDE for related KDE application pages.
Aside from the programs provided in KDE Applications, there are many other applications available that can complement the Plasma desktop. Some of these are discussed below.
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.
- kde-gtk-config — GTK2 and GTK3 Configurator for KDE.
- kcm-gtk — A GTK appearance KConfig Module.
- https://launchpad.net/kcm-gtk || kcm-gtkAUR[broken link: archived in aur-mirror]
- KCM Qt Graphics System — This KCM allows you to easily configure the standard Qt graphics system.
- UFW KControl Module — KDE4 control module for UFW (Uncomplicated Firewall).
- System policies — Set of configuration modules which allows administrator to change PolicyKit settings.
- wacom tablet — KDE GUI for the Wacom Linux Drivers.
- Kcmsystemd — systemd control module for KDE.
More KCMs can be found at linux-apps.com.
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 Plasma desktop, start krunner (default keyboard shortcut 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/
.
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 — Part of the KDE project, supports two rendering engines – KHTML and the Chromium-based Qt WebEngine.
- QupZilla — A Qt web browser with Plasma integration features. It uses Qt WebEngine.
- Chromium — 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.
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. Make sure postgresql.service
is started.
Edit Akonadi configuration file so that it has the following contents:
~/.config/akonadi/akonadiserverrc
[%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 with akonadictl start
, and check its status: akonadictl status
.
SQLite
Edit Akonadi configuration file to match the configuration below:
~/.config/akonadi/akonadiserverrc
[%General] Driver=QSQLITE3 [QSQLITE3] Name=/home/username/.local/share/akonadi/akonadi.db
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).
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.
Tips and tricks
Using an alternative window manager
The component chooser settings in Plasma does not allow changing the window manager anymore. [5]
In order to change the window manager used you need to set the KDEWM
environment variable before KDE startup. [6] To do that you can create a script called set_window_manager.sh
in ~/.config/plasma-workspace/env
and export the KDEWM
variable there. For example to use the i3 window manager :
~/.config/plasma-workspace/env/set_window_manager.sh
export KDEWM=/usr/bin/i3
And then make it executable :
$ chmod +x ~/.config/plasma-workspace/env/set_window_manager.sh
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.
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.
Configuring monitor resolution / multiple monitors
To enable display resolution management and multiple monitors in Plasma, install kscreen. This adds the additional options to Sytem Settings > Display and Monitor.
Disable opening application launcher with Super key (Windows key)
To disable this feature you currently can run the following command:
$ kwriteconfig5 --file kwinrc --group ModifierOnlyShortcuts --key Meta ""
Enabling touchpad tap to click on plasma wayland session
Currently, it is 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 (https://bugs.kde.org/) only if it is an official widget. If it is not, it is recommended you find the entry on https://store.kde.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:
$ cp -a ~/.local/share/akonadi ~/.local/share/akonadi-old $ cp -a ~/.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, see KDE Bug 284172. 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
KF5/Qt5 applications do not display icons in i3/fvwm/awesome
See Qt#Configuration of Qt5 apps under environments other than KDE Plasma.
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 do not refresh properly
If you use 3D-accelerated composition with Intel, you might find that the Plasma panel and other applications do not refresh properly (stay frozen). Some Intel drivers have problems with EGL. Go to System Settings > Display and Monitor > Compositor. Set OpenGL interface to OpenGL 3.1. If that does not work, see Intel graphics#SNA issues for alternative solutions.
Bad performance
Make sure you have the proper driver for your GPU installed. See Xorg#Driver installation for more information. If you have an older card, it might help to #Disable desktop effects[broken link: invalid section] or #Disable compositing.
Disable desktop effects manually or automatically for defined applications
Plasma has desktop effects enabled by default and e.g. not every game will disable them automatically. You can disable desktop effects in System Settings > Desktop Effects and you can toggle desktop effects with Alt+Shift+F12
. Additionally, you can create custom KWin rules to automatically disable/enable compositing when a certain application/window starts under System Settings > Window Management > Window Rules.
Disable compositing
In Sytem Settings > Display and Monitor, uncheck Enable compositor on startup and restart Plasma.
Flickering in fullscreen when compositing is enabled
In Sytem Settings > Display and Monitor, uncheck Allow applications to block compositing. This may harm performance.
Screen tearing with Nvidia
By default, KWin compositing suffers from tearing when used with the proprietary Nvidia driver. To work around this, create a file kwin.sh
in ~/.config/plasma-workspace/env/
with the following contents:
#!/bin/sh export __GL_YIELD="USLEEP"
This however does only work with OpenGL compositing.
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 > Backend.
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.
No Suspend/Hibernate options
If your system is able to suspend or hibernate using systemd but do not have these options shown in KDE, make sure powerdevil is installed.
Problems with saving credentials and persistently occuring KWallet dialogs
It is not recommended to turn off the KWallet password saving system in the user settings as it is required to save encrypted credentials like WiFi passphrases for each user. Persistently occuring KWallet dialogs can be the consequence of turning it off.
In case you find the dialogs to unlock the wallet annoying when applications want to access it, you can let the login managers SDDM
and LightDM
unlock the wallet at login automatically, see KDE Wallet. The first wallet needs to be generated by KWallet (and not user-generated) in order to be usable for system program credentials.
In case you want the wallet credentials not to be opened in memory for every application, you can restrict applications from accessing it with kwalletmanager in the KWallet settings.
If you don't care for credential encryption at all, you can simply leave the password forms blank when KWallet asks for the password while creating a wallet. In this case, applications can access passwords without having to unlock the wallet first.