How Does Steam Function On The Deck (Flatpaks)?

[Modern Retro Gamer (UK)]

So I've been experimenting with Manjaro KDE and Flatpaks while waiting my place in the Deck queue and have discovered that Flatpaks don't work with the Big Picture Mode Overlay and thus games installed as Flatpaks (eg. RetroArch) cannot use the Steam configured controls and are forced to using the Desktop Mode configuration.

This lead to me wondering how this actually works on the Deck?

Is Steam installed as a Flatpak on the Deck or is it baked into the OS?
Does the Deck controls function the same way as the Steam Controller? Are they tied to Big Picture Mode? Does the Steam Overlay need to function for Deck controls to work?
If I installed a Flatpak game, eg. RetroArch, on the Deck, how are the controls mapped?

Thanks.

[ReBoot]

Steam is baked into the OS. The relationship between Steam & SteamOS3 is reversed, similar to how the relationship between the GPU & CPU is reversed on the raspberry pi.

The Deck's controls function simiarly. I wouldn't say "the same way" as they're better. For the desktop that is. Steam must be running for the desktop controls to work, but it may run in background.

Controls are mapped however you're mapping them, that's exactly the same as starting RetroArch downloaded-not-through-Steam on your desktop. You could also download RetroArch from Steam...

[Modern Retro Gamer (UK)]

So how does this work as regard to Flatpaks?

On Manjaro, with the native Steam client install (standard OS package), If I install RetroArch through Steam everything works but I can't set up individual shortcuts for each ROM in the Steam Library.

Installed as a native Linux App (AUP package) everything works as expected.

Installed as a Flatpak, trying to mimic installing Steam through Discover on SteamOS 3, and the controller configs no longer work as the Steam Overlay is not passed through to the Flatpak app. This forces controller mapping via keyboard shortcuts through the Desktop Configuration which is - less than ideal.

I take it in SteamOS the Flatpak sees the controls as a controller so long as Steam is running in the background? Or do Flatpaks, like ReroArch via Discover, only see the controller as Keyboard/Mouse as per ordinary Steam's Desktop Configurations for Big Picture Mode?

[ReBoot]

Why installing Steam via Flatpak? Any reason why you don't want to use the built-in Steam, starting games through that?

As for inputs, it's the same on SteamOS as on Manjaro or Windows: you add X to Steam, then you can configure the input mapping. There's nothing preventing you from giving that X a gamepad through Steam Input.

[Modern Retro Gamer (UK)]

No, Steam is not Install as Flatpak. Steam is installed as a Linux native (built-in) application. The issue, outside of SteamOS - I think, it's what I'm trying to ascertain - is that 3rd party games installed as Flatpaks do not function correctly with the Steam Controls.

So,
- Install any 3rd party game using Flatpak (RetroArch is a good example)
- Add Shortcut To Non-Steam Game in Built-in Steam Clients Library
- Set Up Controller Mappings
- Run Game

What happens when launching said game on SteamOS3/Steam Deck? I assume controller mapping work correctly?

The issue is outside of SteamOS3 - on other Linux Distros - the controller mapping appears not to work as expected. Something in the Flatpak security is stopping the Steam Overlay from running (pressing Guide button while playing game does not bring up the Overlay) which in turn stops the Controller working correctly. Instead we default to the Desktop Configuration which is a Keyboard/Mouse emulation binding, not ideal.

Note - it's the 3rd party game/app (RetroArch, Bottles, Lutris. etc) running as Flatpak, not the Steam Client.

Just trying to understand how Deck Controller mapping differs in this regard to Steam Client and Steam Controllers on other Distros.

Ultimately I do not want to run the Steam version of RetroArch since I want to individually map shortcuts for each ROM and use cores not in the Steam version as standard.

[ReBoot]

Works fine here. I've added a couple of Flatpak-installed stuff as non-Steam games, launching them through Steam, setting inputs via Steam.

[Modern Retro Gamer (UK)]

Pretty much what I thought. I've posted bug reports to both the Flatpak and Linux Steam clients over on Github in the hope a fix may come about one day. The Desktop (K/M) Controller Mappings work fine for what I need today, good to know the issue won't follow me onto the Deck when it comes. Beyond that it seems Steam + Flatpaks = A bad idea outside of SteamOS.

[ReBoot]

There's a slew of people playing emulation on the Deck, there's countless videos, tons of talk about this very stuff on Reddit.

That SteamOS stuff is solved reather neatly. This inversion of control basically means that the SteamOS desktop is still Steam's ♥♥♥♥♥ (except when you close the desktop Steam which runs on the desktop), so to speak. But that's not the fun part. The fun part is to add it to Steam on the desktop and then start it from "gaming mode". That'll get a rather seamless experience (after configuring controls, it's rather likely you'll have to do something about them but that's a one-time ordeal).