After updating to the latest bazzite-deck image (everything after 20250817), the system boots to a black screen. The machine is not frozen — I can reboot with Ctrl+Alt+Del or get a TTY through GRUB — but no GUI appears.
Logs show SDDM autologin repeatedly attempting to launch:
Starting Wayland user session: "/etc/sddm/wayland-session" "gamescope-session-plus steam"
…but the session immediately exits. This repeats in a loop, leaving the screen black.
Rolling back to an older image restores normal operation.
Steps to reproduce
-
Rebase or update to the latest bazzite-deck image.
-
Reboot.
-
Instead of Gaming Mode, only a black screen is shown.
Expected behavior
On boot, SDDM autologin should start Gaming Mode (gamescope-session-plus steam) inside a valid user session (with D-Bus running).
“Switch to Desktop” should open Plasma desktop, not another black screen.
Observed behavior
Boot → black screen (SDDM autologin fails).
“Switch to Desktop” from Gaming Mode also results in a black screen.
Logs (journalctl -b -u sddm) show repeated session start/stop cycles.
GPU (amdgpu) initializes fine; no kernel/DRM errors.
Running Gaming Mode manually with systemd user scope works:
systemctl --user start gamescope-session-plus@steam.service
→ Gaming Mode launches successfully.
This indicates that the issue is how SDDM is launching the session, not gamescope itself.
Environment
Image: bazzite-deck (latest as of <insert date / version>).
Hardware:
- B550 AORUS PRO V2
- AMD Ryzen 7 5800X (16) @ 4.85 GHz
- AMD Radeon RX 9070 XT [Discrete]
- 32GB RAM
Previous image (working): bazzite-deck:42.20250817 (brh rebase bazzite-deck:42.20250817)
Workarounds tested
Start Gaming Mode manually with:
systemctl --user start gamescope-session-plus@steam.service
Works every time.
Directly running /usr/bin/gamescope-session-plus steam fails with:
dbus-update-activation-environment: error: unable to connect to D-Bus
→ Confirms no user D-Bus is available when launched this way.
Root cause hypothesis
The .desktop session file for gamescope-session-plus is being executed by SDDM outside of a user systemd scope, so no session D-Bus is present.
When run via systemctl --user, Gaming Mode works normally.
Therefore, the session file / autologin needs to launch Gaming Mode inside a D-Bus environment or user systemd scope.
Proposed fixes
Option A (simplest): wrap with dbus-run-session
Change the Exec in the session file (e.g. /usr/share/wayland-sessions/gamescope-session-plus.desktop) to:
Exec=/usr/bin/dbus-run-session /usr/bin/gamescope-session-plus steam
This ensures a session bus exists when SDDM launches the session.
Option B (more robust): use systemd user scope
Launch Gaming Mode as a user systemd unit:
Exec=/usr/bin/systemd-run --user --scope --unit=gamescope-session-plus@steam
/usr/bin/gamescope-session-plus steam
This reproduces the manual workaround (systemctl --user start …) that users confirm works, while keeping lifecycle tracking in sync with SDDM.
Additional recommendations
Ship a fallback Plasma session (e.g. plasma.desktop) as the default if the autologin session entry is invalid.
Consider a post-update check that Session= in SDDM’s config points to a valid .desktop file. If not, reset to Plasma to avoid booting into a black screen.
Summary
After update, Bazzite-Deck boots to a black screen because gamescope-session-plus is autologged into without a user D-Bus. Manually starting it with systemctl --user works fine.
→ The session file should be adjusted to launch inside a user D-Bus or user systemd scope.
This will fix both black-screen boot and the “Switch to Desktop” path.
Adding a log that contains this problem:
log-last-boot.txt
After updating to the latest bazzite-deck image (everything after 20250817), the system boots to a black screen. The machine is not frozen — I can reboot with Ctrl+Alt+Del or get a TTY through GRUB — but no GUI appears.
Logs show SDDM autologin repeatedly attempting to launch:
Starting Wayland user session: "/etc/sddm/wayland-session" "gamescope-session-plus steam"
…but the session immediately exits. This repeats in a loop, leaving the screen black.
Rolling back to an older image restores normal operation.
Steps to reproduce
Rebase or update to the latest bazzite-deck image.
Reboot.
Instead of Gaming Mode, only a black screen is shown.
Expected behavior
On boot, SDDM autologin should start Gaming Mode (gamescope-session-plus steam) inside a valid user session (with D-Bus running).
“Switch to Desktop” should open Plasma desktop, not another black screen.
Observed behavior
Boot → black screen (SDDM autologin fails).
“Switch to Desktop” from Gaming Mode also results in a black screen.
Logs (journalctl -b -u sddm) show repeated session start/stop cycles.
GPU (amdgpu) initializes fine; no kernel/DRM errors.
Running Gaming Mode manually with systemd user scope works:
systemctl --user start gamescope-session-plus@steam.service
→ Gaming Mode launches successfully.
This indicates that the issue is how SDDM is launching the session, not gamescope itself.
Environment
Image: bazzite-deck (latest as of <insert date / version>).
Hardware:
Previous image (working): bazzite-deck:42.20250817 (brh rebase bazzite-deck:42.20250817)
Workarounds tested
Start Gaming Mode manually with:
systemctl --user start gamescope-session-plus@steam.service
Works every time.
Directly running /usr/bin/gamescope-session-plus steam fails with:
dbus-update-activation-environment: error: unable to connect to D-Bus
→ Confirms no user D-Bus is available when launched this way.
Root cause hypothesis
The .desktop session file for gamescope-session-plus is being executed by SDDM outside of a user systemd scope, so no session D-Bus is present.
When run via systemctl --user, Gaming Mode works normally.
Therefore, the session file / autologin needs to launch Gaming Mode inside a D-Bus environment or user systemd scope.
Proposed fixes
Option A (simplest): wrap with dbus-run-session
Change the Exec in the session file (e.g. /usr/share/wayland-sessions/gamescope-session-plus.desktop) to:
Exec=/usr/bin/dbus-run-session /usr/bin/gamescope-session-plus steam
This ensures a session bus exists when SDDM launches the session.
Option B (more robust): use systemd user scope
Launch Gaming Mode as a user systemd unit:
Exec=/usr/bin/systemd-run --user --scope --unit=gamescope-session-plus@steam
/usr/bin/gamescope-session-plus steam
This reproduces the manual workaround (systemctl --user start …) that users confirm works, while keeping lifecycle tracking in sync with SDDM.
Additional recommendations
Ship a fallback Plasma session (e.g. plasma.desktop) as the default if the autologin session entry is invalid.
Consider a post-update check that Session= in SDDM’s config points to a valid .desktop file. If not, reset to Plasma to avoid booting into a black screen.
Summary
After update, Bazzite-Deck boots to a black screen because gamescope-session-plus is autologged into without a user D-Bus. Manually starting it with systemctl --user works fine.
→ The session file should be adjusted to launch inside a user D-Bus or user systemd scope.
This will fix both black-screen boot and the “Switch to Desktop” path.
Adding a log that contains this problem:
log-last-boot.txt