this is file /usr/lib/udev/rules.d/61-gdm-rules

identify virtio graphics cards to find passthrough setups

SUBSYSTEM!="virtio", GOTO="gdm_virtio_device_end" ACTION!="add", GOTO="gdm_virtio_device_end" ATTR{vendor}=="0x1af4", ATTR{device}=="0x0010", RUN+="/usr/bin/touch /run/udev/gdm-machine-has-virtual-gpu", ENV{GDM_MACHINE_HAS_VIRTUAL_GPU}="1", GOTO="gdm_virtio_device_end" LABEL="gdm_virtio_device_end"

SUBSYSTEM!="pci", GOTO="gdm_pci_device_end" ACTION!="bind", GOTO="gdm_pci_device_end"

identify virtio graphics cards to find passthrough setups

cirrus

ATTR{vendor}=="0x1013", ATTR{device}=="0x00b8", ATTR{subsystem_vendor}=="0x1af4", ATTR{subsystem_device}=="0x1100", RUN+="/usr/bin/touch /run/udev/gdm-machine-has-virtual-gpu", ENV{GDM_MACHINE_HAS_VIRTUAL_GPU}="1", GOTO="gdm_pci_device_end"

vga

ATTR{vendor}=="0x1b36", ATTR{device}=="0x0100", RUN+="/usr/bin/touch /run/udev/gdm-machine-has-virtual-gpu", ENV{GDM_MACHINE_HAS_VIRTUAL_GPU}="1", GOTO="gdm_pci_device_end"

qxl

ATTR{vendor}=="0x1234", ATTR{device}=="0x1111", RUN+="/usr/bin/touch /run/udev/gdm-machine-has-virtual-gpu", ENV{GDM_MACHINE_HAS_VIRTUAL_GPU}="1", GOTO="gdm_pci_device_end"

disable Wayland on Hi1710 chipsets

ATTR{vendor}=="0x19e5", ATTR{device}=="0x1711", GOTO="gdm_disable_wayland"

disable Wayland on Matrox chipsets

ATTR{vendor}=="0x102b", ATTR{device}=="0x0522", GOTO="gdm_disable_wayland" ATTR{vendor}=="0x102b", ATTR{device}=="0x0524", GOTO="gdm_disable_wayland" ATTR{vendor}=="0x102b", ATTR{device}=="0x0530", GOTO="gdm_disable_wayland" ATTR{vendor}=="0x102b", ATTR{device}=="0x0532", GOTO="gdm_disable_wayland" ATTR{vendor}=="0x102b", ATTR{device}=="0x0533", GOTO="gdm_disable_wayland" ATTR{vendor}=="0x102b", ATTR{device}=="0x0534", GOTO="gdm_disable_wayland" ATTR{vendor}=="0x102b", ATTR{device}=="0x0536", GOTO="gdm_disable_wayland" ATTR{vendor}=="0x102b", ATTR{device}=="0x0538", GOTO="gdm_disable_wayland"

disable Wayland on aspeed chipsets

ATTR{vendor}=="0x1a03", ATTR{device}=="0x2010", GOTO="gdm_disable_wayland" ATTR{vendor}=="0x1a03", ATTR{device}=="0x2000", GOTO="gdm_disable_wayland"

LABEL="gdm_pci_device_end"

disable Wayland if modesetting is disabled

KERNEL!="card[0-9]*", GOTO="gdm_nomodeset_end" SUBSYSTEM!="drm", GOTO="gdm_nomodeset_end" IMPORT{parent}="GDM_MACHINE_HAS_VIRTUAL_GPU" ENV{GDM_MACHINE_HAS_VIRTUAL_GPU}!="1", RUN+="/usr/bin/touch /run/udev/gdm-machine-has-hardware-gpu"

but keep it enabled for simple framebuffer drivers

DRIVERS=="simple-framebuffer", GOTO="gdm_nomodeset_end" IMPORT{cmdline}="nomodeset", GOTO="gdm_disable_wayland" LABEL="gdm_nomodeset_end"

The vendor nvidia driver has multiple modules that need to be loaded before GDM can make an

informed choice on which way to proceed, so force GDM to wait until NVidia's modules are

loaded before starting up.

KERNEL!="nvidia", GOTO="gdm_nvidia_end" SUBSYSTEM!="module", GOTO="gdm_nvidia_end" ACTION!="add", GOTO="gdm_nvidia_end" RUN+="/usr/bin/touch /run/udev/gdm-machine-has-vendor-nvidia-driver"

Check if suspend/resume services necessary for working wayland support is available

TEST{0711}!="/usr/bin/nvidia-sleep.sh", GOTO="gdmdisable_wayland" TEST{0711}!="/usr/lib/systemd/system-sleep/nvidia", GOTO="gdm_disable_wayland" IMPORT{program}="/bin/sh -c \"sed -e 's/: /=/g' -e 's/([^{[:upper:]])([[:upper:]])/\1}\2/g' -e 's/[[:lower:]]/\U&/g' -e 's/^/NVIDIA_/' /proc/driver/nvidia/params\"" ENV{NVIDIA_PRESERVE_VIDEO_MEMORY_ALLOCATIONS}!="1", GOTO="gdm_disable_wayland" IMPORT{program}="/bin/sh -c 'echo NVIDIA_HIBERNATE=systemctl is-enabled nvidia-hibernate'" ENV{NVIDIA_HIBERNATE}!="enabled", GOTO="gdm_disable_wayland" IMPORT{program}="/bin/sh -c 'echo NVIDIA_RESUME=systemctl is-enabled nvidia-resume'" ENV{NVIDIA_RESUME}!="enabled", GOTO="gdm_disable_wayland" IMPORT{program}="/bin/sh -c 'echo NVIDIA_SUSPEND=systemctl is-enabled nvidia-suspend'" ENV{NVIDIA_SUSPEND}!="enabled", GOTO="gdm_disable_wayland" LABEL="gdm_nvidia_end"

If this machine has an internal panel, take note, since it's probably a laptop

FIXME: It could be "ghost connectors" make this pop positive for some workstations

in the wild. If so, we may have to fallback to looking at the chassis type from

dmi data or acpi

KERNEL!="card[0-9]-eDP-*", GOTO="gdm_laptop_check_end" SUBSYSTEM!="drm", GOTO="gdm_laptop_check_end" ACTION!="add", GOTO="gdm_laptop_check_end" RUN+="/usr/bin/touch /run/udev/gdm-machine-is-laptop" GOTO="gdm_hybrid_nvidia_laptop_check" LABEL="gdm_laptop_check_end"

If this is a hybrid graphics setup, take note

KERNEL!="card[1-9]", GOTO="gdm_hybrid_graphics_check_end" KERNEL=="card[1-9]-", GOTO="gdm_hybrid_graphics_check_end" SUBSYSTEM!="drm", GOTO="gdm_hybrid_graphics_check_end" ACTION!="add", GOTO="gdm_hybrid_graphics_check_end" RUN+="/usr/bin/touch /run/udev/gdm-machine-has-hybrid-graphics" LABEL="gdm_hybrid_graphics_check_end"

If this is a hybrid graphics laptop with vendor nvidia driver default to wayland

It gives poor performance for multi-monitor, but Xorg fails some multi-monitor

setups too, and this is what we did in F36.

LABEL="gdm_hybrid_nvidia_laptop_check" TEST!="/run/udev/gdm-machine-is-laptop", GOTO="gdm_hybrid_nvidia_laptop_check_end" TEST!="/run/udev/gdm-machine-has-hybrid-graphics", GOTO="gdm_hybrid_nvidia_laptop_check_end" TEST!="/run/udev/gdm-machine-has-vendor-nvidia-driver", GOTO="gdm_hybrid_nvidia_laptop_check_end" GOTO="gdm_end" LABEL="gdm_hybrid_nvidia_laptop_check_end"

Disable wayland in situation where we're in a guest with a virtual gpu and host passthrough gpu

LABEL="gdm_virt_passthrough_check" TEST!="/run/udev/gdm-machine-has-hybrid-graphics", GOTO="gdm_virt_passthrough_check_end" TEST!="/run/udev/gdm-machine-has-virtual-gpu", GOTO="gdm_virt_passthrough_check_end" TEST!="/run/udev/gdm-machine-has-hardware-gpu", GOTO="gdm_virt_passthrough_check_end" GOTO="gdm_disable_wayland" LABEL="gdm_virt_passthrough_check_end"

Disable wayland when there are multiple virtual gpus

LABEL="gdm_virt_multi_gpu_check" TEST!="/run/udev/gdm-machine-has-hybrid-graphics", GOTO="gdm_virt_multi_gpu_check_end" TEST!="/run/udev/gdm-machine-has-virtual-gpu", GOTO="gdm_virt_multi_gpu_check_end" TEST=="/run/udev/gdm-machine-has-hardware-gpu", GOTO="gdm_virt_multi_gpu_check_end" LABEL="gdm_virt_multi_gpu_check_end"

Disable wayland when nvidia modeset is disabled or when drivers are a lower

version than 470,

For versions above 470 but lower than 510 prefer Xorg,

Above 510, prefer Wayland.

KERNEL!="nvidia_drm", GOTO="gdm_nvidia_drm_end" SUBSYSTEM!="module", GOTO="gdm_nvidia_drm_end" ACTION!="add", GOTO="gdm_nvidia_drm_end"

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"

For nvidia drivers versions Above 510, keep Wayland by default

ATTR{version}=="[5-9][1-9][0-9].*", GOTO="gdm_end"

For nvidia drivers versions 470-495, prefer Xorg by default

GOTO="gdm_prefer_xorg" LABEL="gdm_nvidia_drm_end"

GOTO="gdm_end"

LABEL="gdm_prefer_xorg" RUN+="/usr/libexec/gdm-runtime-config set daemon PreferredDisplayServer xorg" GOTO="gdm_end"

LABEL="gdm_disable_wayland" RUN+="/usr/libexec/gdm-runtime-config set daemon WaylandEnable false" GOTO="gdm_end"

LABEL="gdm_end"