Run FSR 4 on Linux through a Vulkan FSR 4 library #857

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N3oTraX wants to merge 5 commits from linux/fsr4-native into main

N3oTraX commented

2026-11-08 23:19:01 +00:00

(Migrated from github.com)

Makes the FSR 4.1 path of #828 work on native Linux.

Stacked on #828 (which contains #818). Only the last two commits are new here; GitHub also shows the commits of those PRs until they land. I will rebase then.

What changed

Loading: there is no AMD loader for Linux, so the upscaler library itself (amd_fidelityfx_upscaler_vk.so) is loaded with dlopen, from RX_FSR4_DIR or beside the game.
Backend description: the library reads the SDK's older backend type, so ffxCreateBackendVKDesc_DEPRECATED is chained next to the current one. Without it, creation returned FFX_API_RETURN_ERROR_PARAMETER.
VK_EXT_descriptor_buffer: the library records with it. It is requested only when the library is present.
Provider choice: the first of equal versions is kept instead of the last. The library lists Auto, INT8, FP8, so the last one forced FP8 on hardware without it.
Exposure: the library rejects a dispatch without an exposure, and the colour is already tonemapped, so it gets a 1x1 R32_SFLOAT of 1.
BITMAPFILEHEADER joins the POSIX windows.h shim: the menu dump from #818 did not build on Linux.

No AMD binary is added or downloaded. Without a library, the game's upscale stays.

How it was tested


GPU, driver	RX 7900 XTX (RDNA3), RADV Mesa 26.2.6
System	Linux 7.3.1, Hyprland
Game	v131072, build `e0f3ccfa`, Kokiri Forest
Library	third-party fsr4-vk `b0125ea`, built locally from AMD's SDK DLL. Not affiliated with AMD; whether to use it is the user's call
Result	`FSR 4.1.1 Vulkan INT8`, 3416x1440 to 3416x1440, FSR draws the upscale from frame 835, no crash or device lost in the log
Checks	`tests/run_all.py fsr menu upscale resolution`: 5 passed. The full suite was not run

fps before and after: not measured.

The test had to run with RX_VK_NO_WARM=1, RX_VK_NO_PREDICT=1 and RX_VK_PRECOMPILE=0, because v2.0.5 crashes in the driver on this Mesa (#803, precompile_run). It also set RX_VK_ANISO=16.

Not tested

3840x2160 output, and upscaling from 75% or lower.
RDNA2, RDNA4, and FP8.
Windows: not compiled or run here. The Linux code is behind _WIN32 guards; only the provider choice above is shared.

🤖 Generated with Claude Code

Makes the FSR 4.1 path of #828 work on native Linux. > **Stacked on #828** (which contains #818). Only the last two commits are new here; GitHub also shows the commits of those PRs until they land. I will rebase then. ## What changed - **Loading:** there is no AMD loader for Linux, so the upscaler library itself (`amd_fidelityfx_upscaler_vk.so`) is loaded with `dlopen`, from `RX_FSR4_DIR` or beside the game. - **Backend description:** the library reads the SDK's older backend type, so `ffxCreateBackendVKDesc_DEPRECATED` is chained next to the current one. Without it, creation returned `FFX_API_RETURN_ERROR_PARAMETER`. - **`VK_EXT_descriptor_buffer`:** the library records with it. It is requested only when the library is present. - **Provider choice:** the first of equal versions is kept instead of the last. The library lists `Auto`, `INT8`, `FP8`, so the last one forced FP8 on hardware without it. - **Exposure:** the library rejects a dispatch without an exposure, and the colour is already tonemapped, so it gets a 1x1 `R32_SFLOAT` of 1. - `BITMAPFILEHEADER` joins the POSIX `windows.h` shim: the menu dump from #818 did not build on Linux. No AMD binary is added or downloaded. Without a library, the game's upscale stays. ## How it was tested | | | |---|---| | GPU, driver | RX 7900 XTX (RDNA3), RADV Mesa 26.2.6 | | System | Linux 7.3.1, Hyprland | | Game | v131072, build `e0f3ccfa`, Kokiri Forest | | Library | third-party [fsr4-vk](https://github.com/Astyyyyy/fsr4-vk) `b0125ea`, built locally from AMD's SDK DLL. Not affiliated with AMD; whether to use it is the user's call | | Result | `FSR 4.1.1 Vulkan INT8`, 3416x1440 to 3416x1440, FSR draws the upscale from frame 835, no crash or device lost in the log | | Checks | `tests/run_all.py fsr menu upscale resolution`: 5 passed. The full suite was not run | **fps before and after: not measured.** The test had to run with `RX_VK_NO_WARM=1`, `RX_VK_NO_PREDICT=1` and `RX_VK_PRECOMPILE=0`, because v2.0.5 crashes in the driver on this Mesa (#803, `precompile_run`). It also set `RX_VK_ANISO=16`. ## Not tested - 3840x2160 output, and upscaling from 75% or lower. - RDNA2, RDNA4, and FP8. - Windows: not compiled or run here. The Linux code is behind `_WIN32` guards; only the provider choice above is shared. 🤖 Generated with [Claude Code](https://claude.com/claude-code)

madebyjordan commented

2026-11-08 23:27:38 +00:00

(Migrated from github.com)

Thanks for this. Linux support is great, and your provider fix helps Windows too (RDNA 2 has no FP8).

#828 is the shared branch for FSR 4.1, so contributions all land in one place. Could you open this as a PR against madebyjordan/hookshot-amd, branch amd/fsr4? It applies cleanly. One heads-up: since you branched, I made vk_fsr4.cpp Windows-only, which would hide your Linux code. I'll remove that when yours comes in.

If you'd rather not open another PR, I can copy your two commits over myself with your name kept and credit you in #828. Whichever you prefer.

Thanks for this. Linux support is great, and your provider fix helps Windows too (RDNA 2 has no FP8). #828 is the shared branch for FSR 4.1, so contributions all land in one place. Could you open this as a PR against `madebyjordan/hookshot-amd`, branch `amd/fsr4`? It applies cleanly. One heads-up: since you branched, I made `vk_fsr4.cpp` Windows-only, which would hide your Linux code. I'll remove that when yours comes in. If you'd rather not open another PR, I can copy your two commits over myself with your name kept and credit you in #828. Whichever you prefer.

N3oTraX commented

2026-11-08 23:54:46 +00:00

(Migrated from github.com)

Thanks! Opened against amd/fsr4: https://github.com/madebyjordan/hookshot-amd/pull/2. It also removes the Windows-only guard, so you don't have to. I'll keep this one until that lands.

Thanks! Opened against `amd/fsr4`: https://github.com/madebyjordan/hookshot-amd/pull/2. It also removes the Windows-only guard, so you don't have to. I'll keep this one until that lands.

madebyjordan commented

2026-11-08 23:58:15 +00:00

(Migrated from github.com)

Merged into amd/fsr4 (madebyjordan/hookshot-amd#2), so it is part of #828 now, with you credited for Linux support. Thanks for rebasing it onto the new head. Feel free to close this one whenever suits you.

Merged into `amd/fsr4` (madebyjordan/hookshot-amd#2), so it is part of #828 now, with you credited for Linux support. Thanks for rebasing it onto the new head. Feel free to close this one whenever suits you.

N3oTraX commented

2026-11-09 01:07:30 +00:00

(Migrated from github.com)