protonscr

Problems with a Decky-Loader plugin in the newer version of Proton experimental-11.0-20260713

protonopen
ValveSoftware/Proton#9999 · opened 2026-07-23 by stinga11 · updated 2026-07-28 · 1 comments · github
1 matching comments, n / p to jump
Sstinga11 2026-07-23 github

Game name

All games

Steam AppID

all games

Proton version

experimental-11.0-20260713

GPU

RX 5700 XT

Video driver version

26.1.4

Kernel version

Linux 7.1.3-2-cachyos-bore

Symptoms

In the newer version of Proton experimental the Decky-loader plugin, CheatDeck, no longer works. If I open any game in the gamescope-session and press the guide button, the game's trainer should appear, but nothing happens. If I open the game on the desktop and view the open windows with Alt+Tab, the trainer is running, but I can't access it. If I keep trying, a pop-up window appears asking me to force it to close or wait, but it gets stuck in an endless loop until I force it to close. I had to use the Proton 11.0-1because it works perfectly in that version, as it did in all previous versions of Proton Experimental.

I already complained to the creator of CheatDeck and he tells me that in both logs the trainer is running (but as I explained above it runs but cannot be accessed) here I leave exactly what he told me, I don't know if this will help:

The issue appears to be related to window handling in newer Wine/Proton/Gamescope versions, and it is likely an upstream Proton or Wine regression problem.

Steps to reproduce

  1. Install Decky-Loader
  2. Install CheatDeck by sheffeyG
  3. Download any trainer from the flingtrainer website
  4. Try to access the trainer.

Log from experimental-11.0-20260713 (CheatDeck Won't works)

steam-1593500 experimental-11.0-20260713.zip

Log from Proton 11.0-1 (CheatDeck Works)

steam-1593500 proton-11.0-1.zip

VVoidCounsel 2026-07-28 · hidden on GitHub github

This isn’t really a CheatDeck problem.

CheatDeck doesn’t inject anything into the game. It just launches a second Windows executable (the trainer) into the same Proton prefix and lets you switch between the two windows. That second-process pattern is what stopped working in experimental-11.0-20260713 and the other recent Wine 11 builds.

  • Normal single-process games should still be fine
  • Stuff that only sets launch options or environment variables should still be fine
  • Anything that starts another Windows process in the same prefix (CheatDeck trainers, some mod launchers, etc.) is broken

So the regression looks like it’s in how Proton/Wine 11 handles extra processes that share a prefix.

Most likely candidates given the Wine 11 timing:

  1. Process creation / job object changes (especially with NTSync)
  2. Tighter isolation or visibility of secondary processes under gamescope
  3. Changes in how the prefix environment or STEAM_COMPAT_DATA_PATH gets passed to child processes

Seeing the same breakage on proton-cachyos builds that are also on the Wine 11 tree makes it feel like a shared issue rather than something specific to one build.

Would be good to know if other tools that launch a second Windows executable into a Proton prefix are also broken.

Proton versions

Launch options