fedora-kde / SIG

#523 SDDM Wayland is broken on Rawhide / 41
Closed: Fixed by xalt7x. Opened by xalt7x.

Closed: Fixed
Reopen Issue

After rebase from Kinoite 40 to Kinoite Rawhide (pre-41), SDDM Wayland fails to start. There's a black screen with a static (not blinking) terminal cursor. Ctrl+Alt+F{3-12} keys don't switch to another TTY (although it's still possible to restart with Ctrl+Alt+Delete).

I've reproduced this issue on bare metal (3 machines with different GPUs), as well as on KVM (virt-manager with "Video Vitrtio").

I SSH-ed into several machines and systemctl status sddm showed the same error:

May 31 20:19:13 testpc systemd[1]: Started sddm.service - Simple Desktop Display Manager.
May 31 20:19:13 testpc sddm-helper[1124]: pam_unix(sddm-greeter:session): session opened for user sddm(uid=981) by (uid=0)
May 31 20:19:13 testpc sddm-helper[1124]: pam_systemd(sddm-greeter:session): New sd-bus connection (system-bus-pam-systemd-1124) opened.
May 31 20:19:13 testpc sddm-helper[1124]: pam_systemd(sddm-greeter:session): Failed to create session: Job 2552 for unit 'session-c4.scope' failed with 'dependency'
May 31 20:19:13 testpc sddm-helper-start-wayland[1136]: QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-sddm'
May 31 20:19:14 testpc sddm-helper-start-wayland[1136]: "No backend specified, automatically choosing drm\n"
May 31 20:19:14 testpc sddm-helper-start-wayland[1136]: "error: XDG_RUNTIME_DIR is invalid or not set in the environment\nkwin_core: Failed to find a free display socket\nFATAL ERROR: could not add wayland socket \n"
May 31 20:19:14 testpc sddm-helper[1124]: pam_unix(sddm-greeter:session): session closed for user sddm

System can be restored by booting into multi-user.target (add "3" as the boot parameter using editing of the GRUB menu) and applying either of these workarounds:

  • Force X11 for SDDM by installing "sddm-x11" package
    rpm-ostree override remove sddm-greeter-displayserver --install sddm-x11
  • Enable Autologin in /etc/sddm/kde_settings.conf
    [Autologin]
    User=some_username
  • On KVM, for "Video" use "QXL" instead of "Virtio"

Metadata Update from @aleasto:
- Issue assigned to aleasto

I cannot reproduce

The system journal should have more information for why systemd Failed to create session: Job 2552 for unit 'session-c4.scope' failed with 'dependency'.

@aleasto

Today I tried to re-create VM and quickly reproduced it.
How to reproduce with virt-manager:
1.Download latest Kinoite 40 ISO (currently it's Fedora-Kinoite-ostree-x86_64-40-1.14.iso)
2. On virt-manager start creating VM and select "Fedora Silverblue 40" as OS
3. On the last step before installation select "Customize configuration before install"
4. Enable OpenGL for VM:
- On "Display Spice" page set "Listen type" to "none" and enable "OpenGL"
- On "Video Virio" page enable "3d acceleration"
5. Install OS, install updates, enable sshd service
6. Rebase to Rawhide with rpm-ostree rebase fedora:fedora/rawhide/x86_64/kinoite
7. Restart and check if the original issue exists. If you have an issue with home directory creation (https://bugzilla.redhat.com/show_bug.cgi?id=2284340), ~~~rebase to the older image with rpm-ostree deploy Rawhide.20240531.n.0~~~ downgrade "selinux-policy" and "selinux-policy-targeted" packages to version 40.20-1.fc41 (rpm-ostree override replace selinux-policy-*-40.20-1.fc41.noarch.rpm).

The system journal should have more information for why systemd Failed to create session: Job 2552 for unit 'session-c4.scope' failed with 'dependency'.

Unfortunately, I didn't find anything interesting yet.
Edited by xalt7x

I've checked VM today and now there's a blinking curor on a black screen. This time systemctl status sddm shows that service had started. However, some errors were spotted in journalctl -xb

sddm-helper-start-wayland[1337]: "No provider of glBufferStorage found. Requires one of:\n Desktop OpenGL 4.4\n GL_ARB_buffer_storage\n GL_EXT_buffer_storage\n"
Process 1339 (kwin_wayland) crashed and dumped core.
sddm-helper-start-wayland[1337]: "The Wayland connection broke. Did the Wayland compositor die?\n"
sddm-helper-start-wayland[1337]: Stopping... "/usr/bin/sddm-greeter-qt6"

Possibly related KDE bug report - https://bugs.kde.org/show_bug.cgi?id=487777
I'm planning to check patch later this week.
Edited by xalt7x

@aleasto

Unfortunately, even after recent updates, I still have this issue (on both VM and bare metal)
Today, I set the default target to multi-user and disabled the SDDM service so that I could start it manually later and quickly find only SDDM-related information.
As soon as I started the SDDM service, the cursor/screen froze and I could not switch to another TTY on this machine (according to the journal, Ctrl+Alt+F* actually switched TTYs but I didn't see it on the screen). However, it was still possible to SSH, so I've got log using journalctl -xb (attached to this message).

I wasn't able to find anything more specific than these errors:

kwin_core: Could not determine the active graphical session
error: XDG_RUNTIME_DIR is invalid or not set in the environment
kwin_core: Failed to find a free display socket
FATAL ERROR: could not add wayland socket

sddm_wayland__fedora41_2024-06-17.txt

P.S. The issue was not reproduced on KDE Neon Developer Edition (I've created file on /etc/sddm.conf.d/ with content of the /usr/lib/sddm/sddm.conf.d/plasma-wayland.conf from Fedora).
Edited by xalt7x

I've tried Fedora Rawhide KDE Spin on VM and SDDM Wayland works there (on both Live system and post-install).
So I think it could be Fedora Kinoite issue.
@siosm , I saw that you were able to run a Live session of Fedora Atomic. Was SDDM Wayland used there?

I've installed the latest Kinoite Rawhide from https://openqa.fedoraproject.org/nightlies.html using libvirt / QEMU, did the setup (after the first boot, not before) and I have a working SDDM & session.
Edited by siosm

@siosm
I wasn't aware of Fedora Atomic Rawhide ISOs , thanks for the link!
Good news: I've re-tried to reinstall Kinoite 40 (from Fedora-Kinoite-ostree-x86_64-40-1.14.iso), then updated it and rebased to Kinoite Rawhide. This time SDDM didn't break. I've also tried deploying previous versions (down to Rawhide.20240616.n.0) and that also didn't trigger this issue.
Though, on my laptop it's still broken so I have to ~~install sddm-x11~~ rpm-ostree override remove sddm-wayland-plasma there.
Edited by xalt7x

Today I've noticed that KDE Plasma 6.1 landed in Fedora 40 Kinoite and decided to try it on laptop with broken SDDM.
First, I removed all overlayed package (uninstall --all), then rebased to Fedora 40 and SDDM loaded successfully. After rebase to Rawhide the issue returned.
If there's something I can try or any info I can get from Rawhide/41, please let me know.

Edited by xalt7x

For the record, I'm unable to reproduce this as well. Could you provide more information about the laptop you're testing this on?

This is likely https://gitlab.freedesktop.org/mesa/mesa/-/issues/11352

Once again, I've rebased to Kinoite 41 and don't have it anymore.

Metadata Update from @xalt7x:
- Issue close_status updated to: Fixed
- Issue status updated to: Closed (was: Open)
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