Proton Experimental does not enable FSR4 on RDNA4 correctly.

[Hupro]

steam-2909400.log

Using the latest Proton Experimental, when FSR4 is enabled in game on RDNA4, it enables FSR4.1.1 however it using the FSR3 fallback. This was confirmed using optiscaler to use the upscaler watermark. By default the game loads FSR4.1.1 however the watermark shows it is actually using FSR3. Manually switching the game to FSR4.1.0 (using optiscaler) shows the correct MLSR watermark.

I've attached 2 images to illustrate this issue. Unsure if it is helpful in this case but I've also attached the proton log when booting a game and the incorrect upscale model is chosen.

[kisak-valve]

Hello @Hupro, we're using one issue report per unofficially supported game title, so I've gone ahead and transferred this issue report to #8408 (comment).

[Hupro]

I understand, just to be clear this issue applies to all games using FSR4 on Proton Experimental, not just FF7 that was meant as an example. If it is better under a different issue that is fine I wasn't sure how to best report it.

[yashraval97]

I just tried Spiderman 2 with Proton Experimental and even that is running FSR 3.1 instead of FSR4. This is not game specific as @Hupro mentioned. Only way for now to enable FSR4 is either optiscaler or use proton-ge/cachyos.

[SeimusS]

I see exactly the same problem as well for the RDNA4 (9070XT).

Official Valve Proton, be it the Experimental (default) or Bleeding Edge does not enable properly FSR4 or does not upgrade properly FSR3.1 to FSR4 at all. I tested a lot of games, and none of them is running FSR4.

Example some:

• Crimson desert
• KCD2
• Titan Quest 2
• Manor Lords

In order for us RDNA4 users to get FSR4 we have to force it via OptiScaler or use custom protons with the PROTON_FSR4_UPGRADE launch command or set it as environment variable.

[calicomia]

Hi all. just popping in to give my confirmation of this happening on Proton Experimental with my RX 9070 GRE; I confirmed it via Helldivers 2, one of the few games that identifies which ver of FSR is enabled, and it sure as heck says FSR3 by default despite my card being RDNA4

[calicomia]

Hi again all. Just popping in again to add something curious-
I upgraded to my 9070GRE from an RX 7600, which I still have.
When I re-install the 7600 in my rig, as I expected, Proton Experimental defaults to FSR4 just fine.
So it defaults to FSR4 on RDNA3 with that new feature, but the RDNA4 detection seems buggy?

A current workaround I have found is to use Proton-CachyOS. this enables it just fine automatically on my RDNA4 card :)

[dm-zharov]

This is caused by this change:

• amdxc64: Auto-enable upgrade on compatible HW.

Since recently, Proton Experimental bundles the FSR 4.1.1 DLL, which asks the graphics driver to report whether the hardware is compatible. Valve currently allows only RDNA 3 GPUs.

I don't see any technical reason not to add RDNA 4 GPUs to the allowlist, since they're officially supported by AMD.

As a workaround, manually replace:

~/.steam/steam/steamapps/common/Proton - Experimental/contrib/amdxcffx64.dll

with the FSR 4.0.* DLL and set FSR4_UPGRADE=1 launch option. Or use custom Proton, OptiScaler, etc

[ivyl]

I don't see any technical reason not to add RDNA 4 GPUs to the allowlist, since they're officially supported by AMD.

The DLL from contrib/ does not enable FSR4 on RDNA4 with the current state of Proton. It will claim in the options that FSR 4.0.1 is used, as that the version advertised by the DLL itself, but it will render using the FSR3 model.

The reason why we limit it to RDNA3 via the linked commit is to avoid that exact confusion. People would see FSR4 in setting but would get FSR3 anyway.