Valve has clarified that when it comes to which version of a game to run on the Steam Deck, the native Linux incarnation will be used – rather than the Windows game via Proton – if it makes sense to do so. In other words, if the native Linux port runs fine.
There was some confusion around this because some eagle-eyed folks had spotted that Portal 2, one of Valve’s own games that has been ported to Linux, was down in SteamDB as being recommended to run on the Steam Deck via Proton (meaning the Windows version, facilitated by the compatibility layer, Proton, to run on SteamOS which is, of course, a Linux-based operating system).
As Gaming on Linux pointed out, though, in fact this was only the case because of the way Valve implemented the testing of these different versions in the early days of working on software compatibility for the Steam Deck.
Valve explained: “Early on, there were a limited number of titles that were tested via Proton before Linux before we made some policy changes. Since then all of those titles are already back in the queue for re-testing using their Linux builds.”
And if those Linux builds do indeed perform robustly on Valve’s handheld PC, the native Linux version will be the recommended one.
In a developer document detailing the compatibility review process for the Steam Deck, Valve further explains: “By default, we will test a Linux build if one is available. If the Linux build fails compatibility tests or otherwise experiences significant issues, we’ll then test the Windows build of your game running under Proton. Our goal is for customers to have the smoothest experience possible on Deck, so we’ll submit whichever set of test results is more favorable.”
Analysis: Sounds like a plan, but what about those nuances…
This seems like a fair enough way to decide which route to take when any given game actually has a native Linux port. Problems could arise, however, in the checking process when there are nuances like, as PC Gamer (which flagged this up) noted, those seen with Borderlands 2, which may have a native Linux version, but the final DLC doesn’t (so wouldn’t work).
Or to take another example, a Linux build may work better on the face of it, but not have the latest updates and tweaks (perhaps bug fixes, additional content) to the game that the Windows version does. How deep the testing process would go in these cases, and whether such extra factors would be considered – well, the worry is obviously that some of these finer points might be missed.
Also, if the Linux build works fine, but the Proton version offers, say, slightly better performance, that may never be picked up – as Valve notes, it won’t move past testing the Linux incarnation if that’s solid in terms of compatibility and doesn’t throw up any serious issues.
Of course, you’ll still be able to run either the native Linux or the Proton spin of a game as you wish, but less tech-savvy users will clearly go with Valve’s default choice, so may end up being worse off if any of the above kind of gremlins are encountered.
There are a lot of factors in the compatibility stakes for the Steam Deck, and doubtless, there’ll be a lot of ironing out to do on this software side of the equation post-release.