(Note: this is the mutter equivalent of RHEL-45898, since it requires backporting https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4088 into RHEL 10)

What were you trying to do that didn't work?

Trying to start "gdm" on a s390x KVM guest with virtio-gpu graphics card fails if only wayland is available (it still works with gnome-session-xsession though)

Please provide the package NVR for which bug is seen:

gnome-shell-46.2-4.el10.s390x
mutter-46.1-1.el10.s390x
gdm-46.0-3.el10.s390x

How reproducible:

100%

Steps to reproduce

1. virt-install --name r10test --ram=8192 --vcpus=2 --nographics --accelerate \
     --network network=default,model=virtio \
     -l http://.../latest-RHEL-10/compose/BaseOS/s390x/os/ \
     --debug \
     --console pty,target_type=sclp \
     --disk /var/lib/libvirt/images/r10test.qcow2,size=12 --osinfo rhel9-unknown
2. Do a text mode installation of the guest to the whole disk image
3. Shut down the guest
4. Add the virtio-gpu devices, i.e. "virsh edit r10test" and add this to the "<devices>" section: 
     <input type='keyboard' bus='virtio'>
       </input>
       <input type='mouse' bus='virtio'>
       </input>
       <graphics type='vnc' port='-1' autoport='yes' listen='127.0.0.1'>
         <listen type='address' address='127.0.0.1'/>
       </graphics>
       <video>
         <model type='virtio' heads='1' primary='yes'/>
       </video>

1. Start the guest again:
   virsh start --console r10test
2. In the guest:
   dnf install -y gdm
3. In the guest:
   dnf remove -y gnome-session-xsession
4. In the host:
   vncviewer :0
5. In the guest:
   systemctl start gdm

Expected results

GDM login screen shows up in the VNC window

Actual results

VNC window stays black, and there are these error messages in the output of "journalctl":

 gnome-shell[2603]: Page flip failed: drmModeAddFB2 failed (No such file or directory) and drmModeAddFB cannot be used as a fallback because format=0x34325241 (AR24).

 gnome-shell[2603]: Failed to post KMS update: drmModeAddFB2 failed (No such file or directory) and drmModeAddFB cannot be used as a fallback because format=0x34325241 (AR24).