Bug#1109409: gdm3: GDM failed to start with Nvidia and AMD discrete GPUs

[Vipul Goel]

Package: gdm3
Version: 48.0-2
Severity: important

GDM3 fails to start when using a system with both discrete NVIDIA and AMD GPUs,
and the proprietary NVIDIA drivers installed.

>> Jul 15 00:06:53 xyz gdm-launch-environment][2454]: pam_unix(gdm-launch-environment:session): session opened for user Debian-gdm(uid=105) by (uid=0)

While the gnome + wayland session runs fine with the same HW config
using below command

$ dbus-run-session -- gnome-shell --display-server --wayland

More Details

The issue occurs specifically with the proprietary NVIDIA drivers
(tested with both the standard and Tesla variants).

The problem is reproducible on both Debian Trixie and Sid, with all
relevant packages installed from the official Debian Sid repositories.

The problem is reproducible whether the NVIDIA drivers are installed
via the Debian packages or directly from the NVIDIA website.

GDM3 starts successfully when using Nouveau drivers, indicating the
issue is specific with the proprietary NVIDIA stack.

No such issue occurs on Rocky Linux 10 with the NVIDIA drivers from
the official NVIDIA website (gdm3 + Nvidia drivers + wayland).

The problem appears to be specific to Wayland sessions with GDM3; I
have not tested GDM3 under Xorg recently.

Logs
Jul 15 00:06:53 xyz systemd[1]: gdm.service: Scheduled restart job,
restart counter is at 4.
░░ Automatic restarting of the unit gdm.service has been scheduled, as
the result for
Jul 15 00:06:53 xyz systemd[1]: Starting gdm.service - GNOME Display Manager...
░░ Subject: A start job for unit gdm.service has begun execution
░░ A start job for unit gdm.service has begun execution.
Jul 15 00:06:53 xyz systemd[1]: Started gdm.service - GNOME Display Manager.
░░ Subject: A start job for unit gdm.service has finished successfully
░░ A start job for unit gdm.service has finished successfully.
Jul 15 00:06:53 xyz gdm-launch-environment][2454]:
pam_unix(gdm-launch-environment:session): session opened for user
Debian-gdm(uid=105) by (uid=0)
Jul 15 00:06:53 xyz systemd-logind[1363]: New session c10 of user Debian-gdm.
░░ Subject: A new session c10 has been created for user Debian-gdm
░░ A new session with the ID c10 has been created for the user Debian-gdm.
Jul 15 00:06:53 xyz systemd[1]: Started session-c10.scope - Session
c10 of User Debian-gdm.
Jul 15 00:06:53 xyz gdm3[2449]: Gdm: GdmSession: no session desktop
files installed, aborting...
Jul 15 00:06:53 xyz kernel: traps: gdm3[2449] trap int3
ip:7f2eb787025a sp:7ffd9a506a30 error:0 in
libglib-2.0.so.0.8400.3[6725a,7f2eb7828000+a1000]
Jul 15 00:06:53 xyz systemd[1]: gdm.service: Main process exited,
code=killed, status=5/TRAP
░░ An ExecStart= process belonging to unit gdm.service has exited.
Jul 15 00:06:53 xyz systemd[1]: gdm.service: Failed with result 'signal'.
░░ The unit gdm.service has entered the 'failed' state with result 'signal'.
Jul 15 00:06:53 xyz systemd[1]: gdm.service: Triggering OnFailure= dependencies.
Jul 15 00:06:53 xyz systemd[1]: gdm.service: Failed to enqueue
OnFailure=plymouth-quit.service job, ignoring: Unit
plymouth-quit.service not found.
Jul 15 00:06:54 xyz systemd[1]: gdm.service: Scheduled restart job,
restart counter is at 5.
░░ Automatic restarting of the unit gdm.service has been scheduled, as
the result for
Jul 15 00:06:54 xyz systemd[1]: gdm.service: Start request repeated too quickly.
Jul 15 00:06:54 xyz systemd[1]: gdm.service: Failed with result 'signal'.
░░ The unit xyz.service has entered the 'failed' state with result 'signal'.
Jul 15 00:06:54 xyz systemd[1]: Failed to start gdm.service - GNOME
Display Manager.
░░ Subject: A start job for unit gdm.service has failed
░░ A start job for unit gdm.service has finished with a failure.
Jul 15 00:06:54 xyz systemd[1]: gdm.service: Triggering OnFailure= dependencies.
Jul 15 00:06:54 xyz systemd[1]: gdm.service: Failed to enqueue
OnFailure=plymouth-quit.service job, ignoring: Unit
plymouth-quit.service not found.


# ls -al /usr/share/wayland-sessions/
total 20
drwxr-xr-x. 1 root root   68 Jul 15 00:07 .
drwxr-xr-x. 1 root root 3892 Jul 14 22:58 ..
-rw-r--r--. 1 root root 7976 Jul 15 00:06 gnome.desktop
-rw-r--r--. 1 root root 8402 Apr 17 11:41 gnome-wayland.desktop


# lsmod | grep nvidia
nvidia_drm            118784  3
nvidia_modeset       1605632  3 nvidia_drm
nvidia              60702720  35 nvidia_modeset
drm_ttm_helper         16384  3 amdgpu,nvidia_drm
drm_kms_helper        253952  4
drm_display_helper,amdgpu,drm_ttm_helper,nvidia_drm
video                  81920  3 asus_wmi,amdgpu,nvidia_modeset
drm                   774144  24
gpu_sched,drm_kms_helper,drm_exec,drm_suballoc_helper,drm_display_helper,nvidia,drm_buddy,amdgpu,drm_ttm_helper,nvidia_drm,ttm,amdxcp


# lsmod | grep amd
amdgpu              14450688  22
amd_atl                57344  1
edac_mce_amd           28672  0
amdxcp                 12288  1 amdgpu
kvm_amd               217088  5
drm_exec               12288  1 amdgpu
gpu_sched              65536  1 amdgpu
drm_buddy              20480  1 amdgpu
drm_suballoc_helper    12288  1 amdgpu
kvm                  1396736  4 kvm_amd
drm_display_helper    274432  1 amdgpu
drm_ttm_helper         16384  3 amdgpu,nvidia_drm
ttm                   106496  2 amdgpu,drm_ttm_helper
drm_kms_helper        253952  4
drm_display_helper,amdgpu,drm_ttm_helper,nvidia_drm
i2c_algo_bit           16384  1 amdgpu
ccp                   163840  1 kvm_amd
video                  81920  3 asus_wmi,amdgpu,nvidia_modeset
crc16                  12288  2 bluetooth,amdgpu
drm                   774144  24
gpu_sched,drm_kms_helper,drm_exec,drm_suballoc_helper,drm_display_helper,nvidia,drm_buddy,amdgpu,drm_ttm_helper,nvidia_drm,ttm,amdxcp


lscpi output

AMD RX 6400 - 4 GB VRAM
05:00.0 VGA compatible controller: Advanced Micro Devices, Inc.
[AMD/ATI] Navi 24 [Radeon RX 6400/6500 XT/6500M] (rev c7)
05:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Navi
21/23 HDMI/DP Audio Controller

Nvidia RTX 3080 - 10 GB VRAM
0b:00.0 VGA compatible controller: NVIDIA Corporation GA102 [GeForce
RTX 3080 Lite Hash Rate] (rev a1)
0b:00.1 Audio device: NVIDIA Corporation GA102 High Definition Audio
Controller (rev a1)


hwinfo
System Product Name (SKU)
TUF GAMING X570-PRO (WI-FI)
64KiB BIOS
128GiB System Memory
AMD Ryzen 9 5950X 16-Core Processor


System Information:
Debian Release: 13.0
  APT prefers testing-security
  APT policy: (500, 'testing-security'), (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 6.12.37+deb13-amd64 (SMP w/32 CPU threads; PREEMPT)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE,
TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: SELinux: enabled - Mode: Permissive - Policy name: default

Versions of packages gdm3 depends on:
ii  accountsservice                       23.13.9-7
ii  adduser                               3.152
ii  dbus [default-dbus-system-bus]        1.16.2-2
ii  dbus-bin                              1.16.2-2
ii  dbus-daemon                           1.16.2-2
ii  dconf-cli                             0.40.0-5
ii  dconf-gsettings-backend               0.40.0-5
ii  debconf [debconf-2.0]                 1.5.91
ii  gir1.2-gdm-1.0                        48.0-2
ii  gnome-session [x-session-manager]     48.0-1
ii  gnome-session-bin                     48.0-1
ii  gnome-session-common                  48.0-1
ii  gnome-settings-daemon                 48.1-1
ii  gnome-shell                           48.3-1
ii  gnome-terminal [x-terminal-emulator]  3.56.2-1
ii  gsettings-desktop-schemas             48.0-1
ii  libaccountsservice0                   23.13.9-7
ii  libaudit1                             1:4.0.5-1
ii  libc6                                 2.41-9
ii  libgdk-pixbuf-2.0-0                   2.42.12+dfsg-4
ii  libgdm1                               48.0-2
ii  libglib2.0-0t64                       2.84.3-1
ii  libglib2.0-bin                        2.84.3-1
ii  libgtk-3-0t64                         3.24.49-3
ii  libgudev-1.0-0                        238-6
ii  libjson-glib-1.0-0                    1.10.6+ds-2
ii  libkeyutils1                          1.6.3-6
ii  libpam-modules                        1.7.0-5
ii  libpam-runtime                        1.7.0-5
ii  libpam-systemd [logind]               257.7-1
ii  libpam0g                              1.7.0-5
ii  librsvg2-common                       2.60.0+dfsg-1
ii  libselinux1                           3.8.1-1
ii  libsystemd0                           257.7-1
ii  libx11-6                              2:1.8.12-1
ii  libxau6                               1:1.0.11-1
ii  libxcb1                               1.17.0-2+b1
ii  libxdmcp6                             1:1.1.5-1
ii  polkitd                               126-2
ii  procps                                2:4.0.4-8
ii  systemd-sysv                          257.7-1
ii  ucf                                   3.0052
ii  x11-common                            1:7.7+24
ii  x11-xserver-utils                     7.7+11
ii  xfwm4 [x-window-manager]              4.20.0-1

Versions of packages gdm3 recommends:
ii  at-spi2-core                       2.56.2-1
ii  desktop-base                       13.0.3
ii  gnome-session [x-session-manager]  48.0-1
ii  x11-xkb-utils                      7.7+9
ii  xserver-xephyr                     2:21.1.16-1.3
ii  xserver-xorg                       1:7.7+24
ii  zenity                             4.1.90-1

Versions of packages gdm3 suggests:
pn  libpam-fprintd        <none>
ii  libpam-gnome-keyring  48.0-1
pn  libpam-pkcs11         <none>
pn  libpam-sss            <none>
pn  orca                  <none>

Linux xyz 6.12.37+deb13-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.37-1
(2025-07-11) x86_64 GNU/Linux