Missing Wayland login option on NVIDIA desktops

Additional system information:

    $ echo $XDG_SESSION_TYPE
    x11

    $ ls -l /usr/share/xsessions/ | awk '{print $9}' | grep -v '^\.'
    ubuntu.desktop
    ubuntu-xorg.desktop
    unity.desktop

    $ gnome-shell --version
    GNOME Shell 42.5

So, not running Wayland.

Looking at /usr/lib/udev/rules.d/61-gdm.rules

The conditions that cause Wayland to be rejected as an option seem to be:

    # disable Wayland if modesetting is disabled
    IMPORT{cmdline}="nomodeset", GOTO="gdm_disable_wayland

    # disable wayland if nvidia-drm modeset is not enabled
    ATTR{parameters/modeset}!="Y", GOTO="gdm_disable_wayland"

    # disable wayland for nvidia drivers versions lower than 470
    ATTR{version}=="4[0-6][0-9].*|[0-3][0-9][0-9].*|[0-9][0-9].*|[0-9].*", GOTO="gdm_disable_wayland"

So, looking at those conditions:

    Modesetting:

        $ inxi -Gxx
        Graphics:
          Device-1: NVIDIA GK107 [GeForce GT 640] vendor: eVga.com. driver: nvidia
            v: 470.182.03 pcie: speed: 2.5 GT/s lanes: 16 bus-ID: 01:00.0
            chip-ID: 10de:0fc1
          Display: x11 server: X.Org v: 1.21.1.4 compositor: gnome-shell v: 42.5
            driver: X: loaded: nvidia unloaded: fbdev,modesetting,nouveau,vesa
            gpu: nvidia display-ID: :1 screens: 1
          Screen-1: 0 s-res: 1920x1080 s-dpi: 101
          Monitor-1: HDMI-0 res: 1920x1080 dpi: 102 diag: 546mm (21.5")
          OpenGL: renderer: NVIDIA GeForce GT 640/PCIe/SSE2
            v: 4.6.0 NVIDIA 470.182.03 direct render: Yes

        $ grep modesetting /var/log/Xorg.0.log
        [155004.672] (==) Matched modesetting as autoconfigured driver 2
        [155004.802] (II) LoadModule: "modesetting"
        [155004.802] (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so
        [155004.834] (II) Module modesetting: vendor="X.Org Foundation"
        [155004.884] (II) modesetting: Driver for Modesetting Kernel Drivers: kms
        [155004.901] (WW) Falling back to old probe method for modesetting
        [155005.857] (II) UnloadModule: "modesetting"
        [155005.857] (II) Unloading modesetting

      Does that mean modesetting failed to start? And if so, why?

    NVidia DRM:

        $ grep nvidia-drm /var/log/syslog
        May 14 00:45:51 Nagle-LTS kernel: [ 24.035970] [drm] [nvidia-drm] [GPU ID 0x00000100] Loading driver
        May 14 00:45:51 Nagle-LTS kernel: [ 24.035973] [drm] Initialized nvidia-drm 0.0.0 20160202 for 0000:01:00.0 on minor 0

      So nvidia-drm seems to be loaded.

    NVidia driver:

        NVidia driver version 470.182.03 is not lower than 470.
        That regular expression should not match.

Discussion on Ubuntu forums at

    https://ubuntuforums.org/showthread.php?t=2486867

suggested simply commenting out all those tests to force the use of Wayland.

But those tests may be there for a good reason, and forcing Wayland may result in an unstable system.

This bug has a long history, going back to 2019. It's been "fixed" several times now.

Sometimes, they come back.

You can safely comment out those udev rules. They're only there to stop regular users from hitting these issues while Nvidia Wayland support is not production-ready:

https://bugs.launchpad.net/ubuntu/+bugs?field.tag=nvidia-wayland

It's likely some people will only recently have lost the Wayland login option because it was sometimes displayed by mistake until this update: https://launchpad.net/ubuntu/+source/gdm3/42.0-1ubuntu7.22.04.2

So this bug is the design we intended in April 2022, but for some only a recent change that appeared on their machine in April 2023 (after bug 2006059 was fixed).

So, halfway through 2023, where are we on Wayland working out of the box with NVidia GPUs?

I think many people won't notice the bugs, but there are still too many bugs listed with High severity:
https://bugs.launchpad.net/ubuntu/+bugs?field.tag=nvidia-wayland

Yes. I just updated one machine to Ubuntu 22.04.2 LTS, latest updates. Now I get a Wayland option at login and Wayland. But programs which use Vulkan graphics, ones that worked under Xorg, crash with a segmentation fault. I have a gdb backtrace. Now I, or someone else, has to sort out what part of the graphics stack (Rend3, WGPU, Vulkan, NVidia 530 driver) is broken.

Ref: https://github.com/BVE-Reborn/rend3/issues/486

I probably should report that bug somewhere else. Suggestions as to where?

I would recommend:

  ubuntu-bug egl-wayland

or report manually at: https://bugs.launchpad.net/ubuntu/+source/egl-wayland/+filebug
and mention: https://github.com/NVIDIA/egl-wayland/issues/80
which sounds like it's already fixed in Ubuntu 22.10 and later.