KDE/Troubleshooting

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This article contains various sections to help users of KDE software troubleshoot their systems.

Rebuilding the application database

If the KMenu lacks any application or the whole application list, the KDE application database probably needs to be rebuilt. This is also a possible fix for any KMenu related issues, like missing icons.

user $kbuildsycoca5 --noincremental

Akonadi complains about the MySQL config

Start by checking the permissions in /usr/share/config. If they're 700, update them to 755 recursively.

root #

chmod -R 755 /usr/share/config

If that doesn't solve the error, open the akonadi configuration in ~/.config/akonadi/akonadiserverrc and change the default MySQL config. To use a MySQL server and not the local mysqld executable, make sure that MySQL is running.

Black screen after login

Make sure ~/.bash_profile does not have any interactive components like keychain. Check ~/.xsession-errors for the prompt for input.

Screen tearing or flickering when using Radeon graphics drivers

If there is severe flickering or "tearing" when using Radeon based graphics cards, it may be necessary to change the compositor sync settings to something other than the default "Automatic":

CODE Modifying compositor sync settings

System Settings --> Display Monitor --> Compositor --> VSync

Delayed response of KMenu, krunner, etc.

Packages from the dev-qt category provide a gles2-only USE flag which in the past has caused this effect. It is not advised to enable it. If for no good reason this flag is found to be enabled for dev-qt, kde-frameworks/plasma or kde-plasma/kwin, then remove all occurrences of this flag and rebuild affected packages.

Missing shutdown, reboot, suspend, or hibernate buttons

Note
Missing features like these are often symptoms of not using kde-plasma/plasma-meta. It only provides the desktop and is highly configurable with USE flags. Use it.

Make sure that kde-plasma/powerdevil and sys-power/upower are installed. Also check that the user is in the users group.

KDE Plasma high CPU usage

If you are noticing relatively high CPU usage (normally the dbus-daemon or kwin_x11 processes) when running KDE Plasma make sure to check the syslog for errors that look like the following. Normally just tailing the log will enable you to see this right away since the error is thrown at such a high rate.

FILE /var/log/syslog

...
Oct 17 00:30:26 localhost obexd[32399]: obex_server_init failed 
Oct 17 00:30:26 localhost obexd[32401]: OBEX daemon 5.39 
Oct 17 00:30:26 localhost obexd[32401]: obex_server_init failed 
Oct 17 00:30:26 localhost obexd[32403]: OBEX daemon 5.39

This occurs due to being unable to connect to the bluetooth service, you can ensure this is started by running /etc/init.d/bluetooth start on OpenRC systems. To ensure this does not happen on any other start run the following.

root #rc-update add bluetooth

Alternatively bluetooth can be disabled via the GUI.

CODE Modifying Bluetooth settings

System Settings --> Bluetooth --> Advanced Settings --> Enable Bluetooth integration

Compilation failure

dev-qt/qtwebkit is one of the few packages known to consistently fail when the -j value on MAKEOPTS is set too high.

If you see mysterious build failure, try lowering your -j value. The safe value would be the number of processor times thread (not that plus one).

Similar case has been found when compiling with -j option while KDE Plasma is running (observed with dev-qt/qtwebkit and dev-qt/qtwebengine). The build failure would be accompanied with desktop program lagging (or crashing). If this happen, you might want to consider compiling under TTY.

In other case when you see out-of-memory failure, you may want to get rid of pipe on CFLAGS.

Plasma Browser Integration not working in Firefox

For the Plasma Browser Integration to work, not only must kde-plasma/plasma-browser-integration and the browser extension be installed, but also the browser history has to be enabled.

Device permissions issues and missing shutdown/reboot options

When experiencing authorization or permissions issues in an OpenRC profile make sure that sys-auth/elogind is present, properly configured and elogind USE flag is globally enabled.

Missing suspend or hibernate options

Beyond that, suspend and hibernate options depend on that support being enabled in the kernel, see also: Suspend and hibernate.

Can't unmount /home

If an error like this appears:

*   Unmounting /home ...
*   in use but fuser finds nothing  [ !! ]

Reinstalling kde-plasma/plasma-meta without kde-plasma/plasma-vault may help.

FILE /etc/portage/package.use

kde-plasma/plasma-meta -crypt

Pinentry GPG dialogue for KDE Plasma isn't working

For example when using KMail to sign emails with PGP, the private key needs to be decrypted. If this key has a password, a Pinentry dialogue tries to open. To enable the Qt version, these configuration files need to be edited.

FILE ~/.gnupg/gpg.conf

use-agent
# !! Remove this line from file if it exists:
# pinentry-mode loopback

FILE ~/.gnupg/gpg-agent.conf

pinentry-program /usr/bin/pinentry-qt

zkde_screencast_unstable_v1 does not seem to be available when trying to screencast on Wayland

Make sure to install kde-plasma/kwin with the screencast USE flag.

Wrong theme applied to KDE apps outside Plasma

If kde-plasma/plasma-meta is installed, the environment variable QT_QPA_PLATFORMTHEME should be set to kde. If it is not, gui-apps/qt6ct should be installed and QT_QPA_PLATFORMTHEME set to qt6ct.