How does protontricks detects a Proton prefix?

[christophehenry]

I own a Steam Deck and some of my games are installed through Lutris. From what I found, protonprefix also tries to search Proton prefixes from manually added Steam shortcut. The problem is that Lutris populates the shortcut with a command of the form lutris lutris:rungame/game-identifier which, I suppose obscures the wineprefix from protontricks. So is there an alternative way for me to specify the wineprefix to protontricks so I can use it on non-steam game?

[Matoking]

Protontricks detects Wine prefixes managed by Steam. Those are in turn often installed alongside the Steam app itself on the same location (eg. if /mnt/ssd/SteamLibrary/steamapps/common/Half-Life 2 is the installation directory, /mnt/ssd/SteamLibrary/steamapps/compatdata/220/pfx is often the corresponding Wine prefix directory), but not necessarily always.

---

As for Lutris, if you've installed a game using the Wine runner, Lutris manages the Wine prefix itself which is out of scope for Protontricks. Lutris comes with options to run Winetricks or other external applications (it's the wine dropdown menu next to the Play button in Lutris), so you shouldn't need Protontricks anyway.

If you instructed Lutris to install a Windows game via Steam, Lutris often just runs a simple command for Steam to download or launch the game (which means Steam does the heavy lifting and will create the compatdata directory mentioned previously). In this case the Wine prefix is managed by Steam, so you would use Protontricks instead; Lutris doesn't seem to present Winetricks as an option when the prefix is externally managed.

If you added a Steam shortcut to Lutris, then I'm guessing Lutris does either of the two scenarios I mentioned previously, depending on how the game is installed. Steam will not create a Wine prefix unless you specifically add an EXE file as a Steam shortcut. If you're adding a desktop shortcut created by Lutris to Steam, then Steam simply runs that lutris:rungame/game-identifier command passing the buck to Lutris.

[christophehenry]

Ah sorry it seems I forgot to add some context. So Lutris can create Proton prefixes now using either Proton-GE or directly Steam's Proton. I'm using the latter because I expect to benefit from Steam's latest developments with Proton experimental.

But Lutris' embedded winetricks silently fails on Proton prefixes (lutris/lutris#5607) and it doesn't yet implement its own protontricks (lutris/lutris#1646). So the only solution I have to use winetricks verbs (for instance vcrun2019) is protontricks but protontricks doesn't detect Proton prefixes created by Lutris because they're not in the Steam folder.

Also protontricks doesn't seems to respect WINEPREFIX env var.

[Matoking]

Protontricks only supports games installed via Steam.

Also protontricks doesn't seems to respect WINEPREFIX env var.

This is correct! WINEPREFIX is deliberately ignored since Protontricks reads the Steam configuration to determine where Steam games and their prefixes are installed and sets WINEPREFIX accordingly. If your Wine prefix is not handled by Steam, you can't use Protontricks.

Instead, you should use either Winetricks directly or using a wrapper - such as the Winetricks dropdown menu in Lutris. I checked and Lutris can detect and run the Proton binaries already installed by Steam, but in that case the actual Wine prefix is placed elsewhere and managed by Lutris.

If the project name seems confusing, just remember that Protontricks was created when Steam was the only product to use Proton. :)

[christophehenry]

you should use either Winetricks directly or using a wrapper - such as the Winetricks dropdown

Sadly, as I mentioned, Lutris' embedded winetricks won't work on Proton prefixes even created by Lutris and the project had recently limited opening and commenting issues to project's maintainers.

But I understand this is out of scope of this project. Thank you anyway for your time.

[Matoking]

The issue report seems to have been closed since the UMU change should have fixed Winetricks support. I tested Winetricks briefly using Lutris and it seems to work correctly (logs indicate that it's using UMU behind the scenes), so maybe some other issue is preventing it from working?

In any case, that is a Lutris problem so maybe opening a new issue in the Lutris repo might help, the issue you linked is already a year old so things might have changed.