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Revision as of 15:18, 9 July 2013 by Mbriza (talk | contribs) (Created page with "= SDDM as the default KDE display manager instead of KDM = == Summary == Retire KDM as the default display manager of the KDE Fedora Spin in favor of '''SDDM'''. == Owner =...")
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SDDM as the default KDE display manager instead of KDM


Retire KDM as the default display manager of the KDE Fedora Spin in favor of SDDM.


  • Email:,,,,,,
  • IRC: #fedora-kde

Current status

  • Targeted release: Fedora 20
  • Last updated: 2013-07-09
  • Tracker bug: <will be assigned by the Wrangler>

Detailed Description

As described in many articles and discussions, KDM is nearing its end of life and it's time we decided upon the successor.

I'm proposing to switch to SDDM, which is a new project that suits our needs perfectly despite its immaturity:

It's written in C++11/Qt5 (compared to the bits of XDM in KDM), supports QtQuick theming and its upstream is quite active.

Benefit to Fedora

We'll lead the way for other distributions in terms of which DM to provide for KDE Frameworks 5' / Plasma 2.

Instead of bugreports for obsolete and unmaintainable KDM we'll be getting bugreports for fresh SDDM with clean codebase


  • Proposal owners:
    • Create sddm and sddm-kcm packages.
    • Change kde-settings and the spin-kickstarts to provide SDDM package instead of KDM
    • (eventually) exclude KDM from the kde-workspace package
  • Release engineering: N/A (not a System Wide Change)

Upgrade/compatibility impact

Previous versions of Fedora won't be impacted by this change. Their users will have the possibility to switch from whichever DM they were using to SDDM.

SDDM is now lacking some functionality compared to KDM, namely XDMCP, VNC and multi-seat support. They are planned to be added.

How To Test

System preparation:

  • Create some testing users
for i in test1 test2 test3; do useradd --password test $i; done
  • Install and enable SDDM
yum install sddm # when the packages are included in the repositories)
systemctl enable --force sddm.service

Testing itself (basically applies to every DM/DE combination):

1. Log in as test1

2. From the Kickoff menu, select Leave > Switch User > New Session.

  • SDDM greeter should appear

3. Repeat steps 1. and 2. for users test2 and test3

4. Try switching the sessions (VTs) with [Ctrl+Alt+F<x>] keys.

  • test1 should be on VT1 ([Ctrl+Alt+F1]), test2 on VT2 and so on.

5. Try switching the sessions using the Leave > Switch User dialog.

6. Log out user test2 and switch to test1, then use the Leave -> Switch User dialog to switch to test3.

7. Use the Leave > Switch User > New Session dialog to log test2 again.

User Experience

KDE Spin login screen's appearance changes.

Login screen configuration menu in systemsettings will be different (upstream provides its own KCM module)


Only dependent package will be sddm-kcm, providing the configuration module for SDDM.

Coordination with other maitainers won't be necessary now. However it is possible other DEs will decide to use SDDM as their default DM in future releases.

Contingency Plan

Continue to use KDM as the default KDE Spin display manager.



Release Notes