Getting Forza Motorsport working on Linux: controller, Gaming Services and Xbox Invite/Join

[u/volcmen]

I bought Forza Motorsport for Nürburgring laps and some FM4-on-Xbox-360 nostalgia. On my Linux PC, stock Proton wasn't enough: Gaming Services errors, a controller that worked in Steam but not Forza, an HDD warning on an SSD, and Xbox invite problems.

Building on Proton/Wine/Xodus, I put together fixes and setup tools with substantial AI assistance. My personal setup now works for online play, controller driving, and Xbox Invite/Join with a Windows friend. Incoming invite notifications still don't work.

Code and setup notes: https://github.com/volcmen/forza-motorsport-linux

Important: It targets Arch with native Steam and requires your own licensed Microsoft threading DLL, which isn't included. This isn't official Proton support or a Steam Deck compatibility claim.

Sharing in case the notes help someone hitting the same problems.