Intel Wants Faster XeSS Upscaling Inside Valve's Proton

Intel has opened a set of pull requests that would let its XeSS upscaler run on the dedicated XMX hardware of Intel graphics chips when a Windows game is played through Valve's Proton on Linux. The change is aimed at the slower fallback path that Proton users get today. As of October 20, the requests are open and have not been merged, and Valve has not said anything publicly about them.

What Intel is proposing

Phoronix reported the news on October 19, and PC Gamer followed on October 20. According to both, an Intel engineer, Damian Tomczak, submitted the work. He describes the main change as a built-in libxess.dll that forwards XeSS calls from Direct3D 12 (the graphics interface most modern Windows games use) to the Linux version of the XeSS library, libxess.so. In his words, this lets XeSS use XMX "under Proton instead of the slower fallback path."

The work is split across several projects, because Proton is built from several parts:

• Wine: adds the built-in libxess.dll that hands calls over to the Linux library.
• VKD3D-Proton: turns on the Vulkan features XeSS needs and converts Direct3D 12 objects to Vulkan.
• DXVK: stops hiding Intel graphics branding when Proton supplies XeSS.
• Proton: uses a native libxess.so when one is available and updates the three parts above.

The Proton pull request, number 10289, says it should go in last because it updates the other three. Its description says Proton looks for the Linux library in a user-set location first, then in its own folder, then in the system library path. It uses that library only if its version is at least as new as the one bundled with the game. Otherwise the game's own XeSS file is used, as it is now. When we checked the page on October 20, it was still open and unmerged.

XeSS, XMX and Proton in plain terms

An upscaler renders a game at a lower resolution and then rebuilds a sharper image. If you want the full background, see our guide to how DLSS, FSR and PSSR upscaling works.

XeSS is Intel's version. PC Gamer explains that it works in one of two ways. The DP4a mode is a general method that runs on graphics chips from many vendors. The XMX mode uses special matrix-math units built into Intel's own GPUs, and it is the preferred option. The same article calls XMX "the fast upscaler", which fits Intel's own description of the fallback as slower.

Proton is Valve's compatibility layer. It lets games made for Windows run on Linux, and it is a big reason the Steam Deck and SteamOS can play so many titles.

Why handheld players might care

PC Gamer notes that some of the best handheld PCs now use Intel processors, for example the MSI Claw 8 EX AI+ with an Intel Arc G3 Extreme chip. That machine runs Windows. The article also says Valve has historically supported only AMD chips with SteamOS, though it adds that Valve has improved compatibility with recent AMD and Intel platforms in SteamOS releases this year.

Seen that way, the outlet suggests the change could eventually bring XMX-accelerated XeSS to SteamOS, which would help future Intel-powered handhelds. That is PC Gamer's reading of the situation. Valve has not confirmed any plan, and the pull requests only change Proton, not SteamOS itself. SteamOS is the operating system on the Steam Deck, and it uses Proton to run Windows games.

What is not known yet

Several things are open:

• Whether Valve will accept the pull requests, and how long a review might take.
• Which Proton release would include the code, if it is accepted.
• How much faster XMX XeSS would be than the fallback path on Linux. Neither article gives benchmarks.
• Whether any official SteamOS release will support Intel handhelds in a way that makes this useful.

Phoronix expects the work to be merged in due course, given similar upscaling support for AMD and NVIDIA. That is an expectation, not a commitment. If you play on an Intel GPU under Linux today, nothing changes yet. Watch the Proton pull request and the next Proton release notes for the first sign that the code has been accepted.