Ubuntu22: GDM does not report missing GPU -> use reliable lightdm instead? #998

marc-hb · 2023-01-24T23:10:35Z

marc-hb
Jan 24, 2023
Maintainer

Yet more GDM fun after

Ubuntu 22: Wayland aborts without a connected monitor. No hotplug either + Xorg weird crash #964 ...

Recent systems don't have any functional GPU when using a kernel too old:

Jan 24 21:46:55 sh-mtlp-rvp-hda-02 kernel: i915 0000:00:02.0: Your graphics device 7d55 is not properly supported by the driver in this
                                           kernel version. To force driver probe anyway, use i915.force_probe=7d55
                                           module parameter or CONFIG_DRM_I915_FORCE_PROBE=7d55 configuration option,
                                           or (recommended) check for kernel updates.

$ sudo grep -i connected /sys/kernel/debug/dri/0/i915_display_info
grep: /sys/kernel/debug/dri/0/i915_display_info: No such file or directory

On those GPU-less systems, GDM crashes and then pretends everything is fine ("SUCCESS")

sh-mtlp-rvp-hda-02:~$ systemctl status gdm
● gdm.service - GNOME Display Manager
     Loaded: loaded (/lib/systemd/system/gdm.service; static)
     Active: active (running) since Tue 2023-01-24 22:52:51 UTC; 1min 26s ago
    Process: 9145 ExecStartPre=/usr/share/gdm/generate-config (code=exited, status=0/SUCCESS)
   Main PID: 9150 (gdm3)
      Tasks: 3 (limit: 18758)
        CPU: 601ms
     CGroup: /system.slice/gdm.service
             └─9150 /usr/sbin/gdm3

Jan 24 22:53:03 sh-mtlp-rvp-hda-02 gdm3[9150]: Gdm: GdmDisplay: Session never registered, failing
Jan 24 22:53:03 sh-mtlp-rvp-hda-02 gdm3[9150]: Gdm: Child process -9265 was already dead.
Jan 24 22:53:03 sh-mtlp-rvp-hda-02 gdm-launch-environment][9279]: pam_unix(gdm-launch-environment:session): session opened for user gdm(uid=127) by (uid=0)
Jan 24 22:53:03 sh-mtlp-rvp-hda-02 gdm-launch-environment][9279]: pam_unix(gdm-launch-environment:session): session closed for user gdm
Jan 24 22:53:03 sh-mtlp-rvp-hda-02 gdm3[9150]: Gdm: GdmDisplay: Session never registered, failing
Jan 24 22:53:03 sh-mtlp-rvp-hda-02 gdm-launch-environment][9279]: GLib-GObject: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
Jan 24 22:53:03 sh-mtlp-rvp-hda-02 gdm3[9150]: Gdm: GdmLocalDisplayFactory: maximum number of X display failures reached: check X server log for errors
Jan 24 22:53:03 sh-mtlp-rvp-hda-02 gdm3[9150]: Gdm: Child process -9284 was already dead.
Jan 24 22:53:03 sh-mtlp-rvp-hda-02 gdm3[9150]: Gdm: GdmDisplay: Session never registered, failing
Jan 24 22:53:03 sh-mtlp-rvp-hda-02 gdm3[9150]: Gdm: Child process -9284 was already dead.

Then the only "messenger" is... pipewire-media-session!! Go figure.

systemctl --user --wait is-system-running
degraded
+ systemctl --user --no-pager --failed
  UNIT                           LOAD   ACTIVE SUB    DESCRIPTION
● pipewire-media-session.service loaded failed failed PipeWire Media Session Manager

It gets even worse: when using AutomaticLoginEnable=true in /etc/gdm3/custom.conf then GDM goes into an infinite crashing loop spamming the logs massively - all while still lying to systemd and pretending everything is fine.

Error handling code and other unusual code paths: never tested!

marc-hb · 2023-01-27T23:15:42Z

marc-hb
Jan 27, 2023
Maintainer Author

I tested lightdm and it's a winner absolutely everywhere, thanks @fredoh9 for the suggestion. Failures to use a missing GPU are reported perfectly and it does not crash loop, not even when using autologin.

systemctl --failed
● gpu-manager.service loaded failed failed Detect the available GPUs and deal with any system changes
● lightdm.service     loaded failed failed Light Display Manager

apt-get install lightdm

# Yes, this surprisingly shows an interactive menu to choose between gdm3 and something else
dpkg-reconfigure gdm3

# much faster than reboot + no risk of unexpected kernel switch
systemctl isolate rescue && systemctl isolate default

For autologin create this file /etc/lightdm/lightdm.conf.d/autologin.conf

[SeatDefaults]
autologin-user=ubuntu

WARNING: lightdm suspends the system by default https://askubuntu.com/questions/1337649/how-to-disable-suspend-in-20-minutes-from-the-lightdm-login-screen

1 reply

marc-hb Jun 22, 2023
Maintainer Author

It gets even worse: when using AutomaticLoginEnable=true in /etc/gdm3/custom.conf then GDM goes into an infinite crashing loop spamming the logs massively - all while still lying to systemd and pretending everything is fine.

This crash loop does NOT happen when there is an LCD panel. In that case Xorg successfully finds some EFI framebuffer at /dev/fb0 and everything works normally - even without i915.


Jun 22 22:45:43 jf-mtlp-rvp-nocodec-6 kernel: efifb: probing for efifb
Jun 22 22:45:43 jf-mtlp-rvp-nocodec-6 kernel: efifb: framebuffer at 0x4000800000, using 32400k, total 32400k
Jun 22 22:45:43 jf-mtlp-rvp-nocodec-6 kernel: efifb: mode is 3840x2160x32, linelength=15360, pages=1
Jun 22 22:45:43 jf-mtlp-rvp-nocodec-6 kernel: efifb: scrolling: redraw
Jun 22 22:45:43 jf-mtlp-rvp-nocodec-6 kernel: efifb: Truecolor: size=8:8:8:8, shift=24:16:8:0
Jun 22 22:45:43 jf-mtlp-rvp-nocodec-6 kernel: Console: switching to colour frame buffer device 480x135
Jun 22 22:45:43 jf-mtlp-rvp-nocodec-6 kernel: fb0: EFI VGA frame buffer device


/usr/libexec/gdm-x-session[792]: (II) FBDEV(0): hardware: EFI VGA (video memory: 32400kB)

marc-hb · 2023-11-02T23:40:54Z

marc-hb
Nov 2, 2023
Maintainer Author

To reproduce:

systemctl stop gdm3
systemctl stop lightdm
# replace 0000:00:02.0 with your GPU address, try `lspci`
echo 0000:00:02.0 > /sys/bus/pci/drivers/i915/unbind
modprobe -r i915

systemctl restart gdm3

0 replies

kv2019i · 2023-11-08T17:12:07Z

kv2019i
Nov 8, 2023
Collaborator

I think for DUTs where we don't have i915 yet, it's perfectly ok to run withour graphics up (no need to boot up desktop). This will not affect the test coverage for sof-test.

1 reply

marc-hb Nov 8, 2023
Maintainer Author

Thank you @kv2019i ! So the "fix" is then this:

systemctl mask --now gdm3
systemctl mask --now lightdm
systemctl isolate rescue # "systemctl stop gdm3" is not enough
systemctl isolate default

marc-hb · 2023-12-12T21:35:44Z

marc-hb
Dec 12, 2023
Maintainer Author

New variation on the same thing:
The crash loop now keeps trying to use wayland instead of X11. This reduces the log spam from a ~500 lines/second average to a ~50 lines/second average, which means it flies just under the radar of my new "log flood detector"
237048daa9042 / #1125

HOWEVER, that crash DOES get reported in systemctl --user is-system-running! So it does not go unnoticed.

systemctl --user status [email protected] 
...
gnome-shell[45240]: Failed to setup: No GPUs with outputs found

The "fix" for devices without a connected display is now:

systemctl mask --now gdm
reboot

Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Failed to start Application launched by gnome-session-binary.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Started GNOME Session Manager (session: ubuntu).
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Reached target GNOME Session Manager is ready.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Starting GNOME Shell on Wayland...
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Starting GNOME Shell on X11...
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 gnome-session[1919]: gnome-session-binary[1919]: GnomeDesktop-WARNING: Could not create transient scope for PID 1933: GDBus.Error:org.freedesktop.DBus.Error.UnixProcessIdUnknown: Process with ID 1933 does not exist.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 gnome-session-binary[1919]: GnomeDesktop-WARNING: Could not create transient scope for PID 1933: GDBus.Error:org.freedesktop.DBus.Error.UnixProcessIdUnknown: Process with ID 1933 does not exist.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: [email protected]: Skipped due to 'exec-condition'.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Condition check resulted in GNOME Shell on X11 being skipped.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: [email protected]: Scheduled restart job, restart counter is at 1.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Started Application launched by gnome-session-binary.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Stopped GNOME Shell on X11.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Starting GNOME Shell on X11...
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: [email protected]: Skipped due to 'exec-condition'.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Condition check resulted in GNOME Shell on X11 being skipped.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: [email protected]: Scheduled restart job, restart counter is at 2.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Stopped GNOME Shell on X11.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Starting GNOME Shell on X11...
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: [email protected]: Skipped due to 'exec-condition'.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Condition check resulted in GNOME Shell on X11 being skipped.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: [email protected]: Scheduled restart job, restart counter is at 3.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Stopped GNOME Shell on X11.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: [email protected]: Start request repeated too quickly.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: [email protected]: Skipped due to 'exec-condition'.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Started GNOME Shell on X11.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 gnome-shell[1937]: Running GNOME Shell (using mutter 42.9) as a Wayland display server
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: [email protected]: Failed with result 'protocol'.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Failed to start GNOME Shell on Wayland.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: [email protected]: Triggering OnFailure= dependencies.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Stopped target GNOME Wayland Session.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Stopped target GNOME Session Manager is ready.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Stopped target GNOME Shell.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Stopping GNOME Session Manager (session: ubuntu)...
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Condition check resulted in Disable GNOME Shell extensions after failure being skipped.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Stopped GNOME Session Manager (session: ubuntu).
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Stopped target Tasks to be run before GNOME Session starts.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Reached target Shutdown running GNOME Session.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Stopping Start gnome-keyring as SSH agent...
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Stopping Monitor Session leader for GNOME Session...
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Starting Restart DBus after GNOME Session shutdown...
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Stopped Monitor Session leader for GNOME Session.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Stopped Start gnome-keyring as SSH agent.
Dec 12 21:17:22 jf-mtlp-rvp-sdw-2 systemd[713]: Started Restart DBus after GNOME Session shutdown.

(repeat)

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Ubuntu22: GDM does not report missing GPU -> use reliable lightdm instead? #998

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Ubuntu22: GDM does not report missing GPU -> use reliable lightdm instead? #998

marc-hb Jan 24, 2023 Maintainer

Replies: 4 comments · 2 replies

marc-hb Jan 27, 2023 Maintainer Author

marc-hb Jun 22, 2023 Maintainer Author

marc-hb Nov 2, 2023 Maintainer Author

kv2019i Nov 8, 2023 Collaborator

marc-hb Nov 8, 2023 Maintainer Author

marc-hb Dec 12, 2023 Maintainer Author

marc-hb
Jan 24, 2023
Maintainer

Replies: 4 comments 2 replies

marc-hb
Jan 27, 2023
Maintainer Author

marc-hb Jun 22, 2023
Maintainer Author

marc-hb
Nov 2, 2023
Maintainer Author

kv2019i
Nov 8, 2023
Collaborator

marc-hb Nov 8, 2023
Maintainer Author

marc-hb
Dec 12, 2023
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