Forza Horizon 5 does not recognize Logitech G920 wheel on SteamOS, Steam Deck

[Boballen55]

Your system information

• Steam client version:
• SteamOS version: Operating System: SteamOS 3.7.17 Build: 20251027.1
• Opted into Steam client beta?: [No]
• Opted into SteamOS beta?: [No]
• Have you checked for updates in Settings > System?: [Yes]

Please describe your issue in as much detail as possible:

Summary:
Forza Horizon 5 fails to recognize a Logitech G920 steering wheel on SteamOS (Steam Deck), even though the device is fully functional at the Linux input layer and is accessible to Proton via hidraw. The same wheel and game work correctly on desktop Popos 24.04 using Proton without special configuration.

This appears to be a SteamOS-specific input routing or container limitation affecting non-gamepad HID devices (steering wheels).

Chatgpt was holding my hand through this and this is it's summary, I don't see any hallucination.

Hardware:

• Device: Steam Deck (LCD)
• Wheel: Logitech G920 Driving Force Racing Wheel (USB)
• official Deck Dock

Wheel USB IDs:

• Default mode: 046d:c261
• HID mode (after switch): 046d:c262

Software:

• SteamOS: Current stable (kernel 6.11.x)
• Steam Client: Stable
• Game: Forza Horizon 5 (Steam)
• Runtime: Proton (multiple versions tested)

What works (confirmed):

• Wheel successfully switches to HID mode (046d:c262)
• Kernel binds correctly (usbhid, hid-logitech)
• Device nodes present:
  • /dev/input/event*
  • /dev/input/js*
• evtest works as user "deck" (no sudo)
• joydev interface present
• Wheel events visible during gameplay via evtest
• /dev/hidraw12 (wheel) is opened by winedevice.exe under Proton
• No permission or ACL issues

What does NOT work:

• Forza Horizon 5 does not respond to wheel input
• Wheel unusable in-game
• Steam controller UI shows no usable controller
• Behavior persists in:
  • Desktop Mode
  • Gaming Mode
  • Steam Input disabled
  • PROTON_ENABLE_HIDRAW=1
  • SDL_JOYSTICK_HIDAPI=0
  • After clearing FH5 input cache

Expected behavior:
If Proton has access to the wheel via hidraw and Linux input nodes are functional, Forza Horizon 5 should bind the wheel as it does on desktop Linux.

Actual behavior:
Forza Horizon 5 never binds the wheel on SteamOS, despite:

• hidraw access
• evdev/joydev working
• Proton opening the device

Comparison:

• Pop!_OS 24.04: Works without tinkering

Steps for reproducing this issue:

1. Steam Deck LCD plugged into Steam Dock
2. Plug in logitech g920
3. attempt to get the wheel to work in a game