And i'm not sure, but i think it's also only on opengl games?

I've been researching, and i've come to guess that this is due to the overlay being 32 bit. All the while, for flatpak apps 32-bit support, it needs to be added per app in their manifest, otherwise, no 32 bit libraries for said app,. Most flatpak games don't have this. To me, best course of actions are :

• a 64-bit overlay client or;
• communicate with the flatpak team to have the --allow=multiarch option mounts org.freedesktop.Platform.Compat.i386 to the appropriate directory within the namespace and also giving information to the dynamic library loader where it is.

the overlay in Steam Deck's gamemode is integrated to gamescope, bypassing any need to inject to games.

I've been researching, and i've come to guess that this is due to the overlay being 32 bit

I don't think that's it. For the LD_PRELOAD code-injection used on desktop, both 32- and 64-bit versions of the overlay module exist: 32-bit games must load the 32-bit gameoverlayrenderer.so, 64-bit games must load the 64-bit gameoverlayrenderer.so, and the opposite is not possible. Because Steam doesn't know whether your game is 32-bit, 64-bit or even a mixture of the two, the way it sets up the LD_PRELOAD is to try to load both. Whichever overlay is successfully loaded, you will get an error message for the other one (but that error message is harmless and does not actually mean that the overlay module was not loaded).

A more likely reason for this to be broken for Flatpak non-Steam games is that the Steam overlay assumes that various aspects of process state are shared between Steam and the game, including /tmp and the process ID namespace - but Flatpak's sandboxing means that non-Steam games installed via Flatpak do not share those aspects of their process state with the un-sandboxed Steam.

(This is the same reason why the various versions of Steam Linux Runtime share the process ID namespace with Steam - we originally tried using a new process ID namespace for the game-specific container, but that broke the overlay.)

I tried that with libretro flatpak, that I think is 64-bit. I get many occurances of this:

ERROR: ld.so: object '/home/dkl/.local/share/Steam/ubuntu12_32/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS32): ignored.

and only a single message of this

ERROR: ld.so: object '/home/dkl/.local/share/Steam/ubuntu12_64/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS64): ignored.

So it fails to load both 32 and 64 bit library, and of course the overlay doesn't work. The overlay works for me for non-Flatpak non-Steam games with no problem.

1. flatpak game

Sorry for the silly question, but did you try using the Steam Overlay on games from Flathub, or am I mistaken?

Has anyone had success with workarounds for this? For example, I'm trying to run the Flatpak of retrodeck as a non-steam game (imported into steam via Boilr). At this point just launching retrodeck outside of steam, but I'd really like to use steam-big-picture as the primary launcher UI

Running steam via flatpak on ubuntu 24.04

You can workaround this by using gamescope. That is running steam inside gamescope, since this will make the steam overlay integrated into gamescope instead of injected into the game. Idk if running steam normally and then running the flatpak game(flatpak) inside gamescope(host) fixes this tho

gamescope --steam --extra-args -- steam -gamepadui

You can workaround this by using gamescope. That is running steam inside gamescope, since this will make the steam overlay integrated into gamescope instead of injected into the game. Idk if running steam normally and then running the flatpak game(flatpak) inside gamescope(host) fixes this tho

gamescope --steam --extra-args -- steam -gamepadui

From my attempts, when you try to run Gamescope from normal steam with the "--steam" option it fails to launch because Steam is already running, and if you drop the "--steam" option the game launches but the Steam overlay doesn't work. Running Steam in Gamescope on Desktop has the drawback that Gamescope isn't supposed to be run alongside another Desktop environment and doing so breaks the "Switch to Desktop" option, i.e. you can't return to Desktop using just controller input like you would if you were using Big Picture instead, which is a bit of a problem on the Steam Deck.

Is there any update on this? Tried looking around and it seems to be a dead end. Trying to get Steam overlay working on Bazzite in desktop mode with non-Steam games that are flatpaks (melonDS, Azahar, etc).

Y a-t-il des nouvelles à ce sujet ? J'ai essayé de regarder autour de moi et cela semble être une impasse. J'essaie de faire fonctionner la superposition Steam sur Bazzite en mode bureau avec des jeux non Steam qui sont des flatpaks (melonDS, Azahar, etc.).

No, we don't have any news on that, sorry

Is there seriously no known workaround at all? Flatpak straight up cannot use Steam Input?