Public bug reported:
Package: gdm3
Ubuntu Version: 25.10 (Questing), Kernel 6.17.0-22-generic
GNOME Shell Version: 49.0
GPU: NVIDIA GTX 1650 (driver 580.126.09) + AMD Radeon Vega integrated
(hybrid/Optimus)
Prime Mode: on-demand
Description:
GDM3 fails to authenticate users. The greeter loads successfully, password is
accepted, but the session immediately crashes and returns to the login screen
with no error shown to the user.
Key journal errors:
Gdm: GdmDisplay: Session never registered, failing
gnome-shell: Failed to start gdm-password verification for user:
Gio.IOErrorEnum: The connection is closed
gnome-shell: Gio.IOErrorEnum: The connection is closed
Could not find suitable cursor plane format for /dev/dri/card1, disabling HW
cursor
What works:
LightDM → XFCE session works perfectly
startxfce4 from TTY works
GDM3 greeter displays correctly
Password is accepted (PAM authenticates successfully per logs)
GNOME Shell starts, registers session briefly, then crashes
What does not work:
GDM3 → any session (XFCE or GNOME)
GDM3 → Wayland or X11
Steps to reproduce:
Fresh boot on Ubuntu 25.10 with NVIDIA 580 driver + hybrid GPU
GDM3 set as default display manager
Enter correct password at login screen
Session crashes, returns to GDM3 greeter immediately
Fixes attempted (none resolved GDM3):
WaylandEnable=false in /etc/gdm3/custom.conf
Installed libnvidia-egl-wayland1 v1.1.18-1 from archive.ubuntu.com
Commented out pam_gnome_keyring.so in /etc/pam.d/gdm-password
Fixed /var/lib/gdm3 ownership to gdm:gdm, permissions 750
Added nvidia-drm.modeset=1 to GRUB cmdline
Added nvidia.NVreg_EnableGpuFirmware=0 to GRUB cmdline
Verified wayland libraries point to /lib/x86_64-linux-gnu/ (correct, no AMD
override)
Reinstalled gdm3 (not possible — package not downloadable from repos)
Reinstalled gnome-shell (not possible — package not downloadable from repos)
Current workaround: LightDM with XFCE session.
Installed NVIDIA packages relevant to issue:
nvidia-utils-580: 580.126.09
linux-modules-nvidia-580-open-6.17.0-22-generic
libnvidia-egl-wayland1: 1:1.1.18-1
nvidia-firmware-580-580.126.09
nvidia-prime: 0.8.17.2 (on-demand mode)
** Affects: gdm3 (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/2148808
Title:
GDM3 crashes on password verification with GNOME 49 + NVIDIA 580 on
Ubuntu 25.10 — Gio.IOErrorEnum: The connection is closed
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