DXVK-NVAPI

Experimental non-complete NVAPI implementation on top of DXVK

This repository provides a basic alternative implementation of the NVAPI extensions for DXVK. Its way of working is very similar to DXVK-AGS, but adjusted for NVAPI.

This implementation currently forwards the following NVAPI D3D11 features to DXVK:

SetDepthBoundsTest
BeginUAVOverlap/EndUAVOverlap
MultiDrawInstancedIndirect/MultiDrawIndexedInstancedIndirect

It also implements several methods for adapter/display topology and system information. Some of those are a requirement for enabling other NVIDIA related technologies.

This implementation has been mostly tested with Unreal Engine 4, with the game Assetto Corsa Competizione and several UE4 technology demos. Unreal Engine 4 utilizes SetDepthBoundsTest, newer engine versions also utilize BeginUAVOverlap/EndUAVOverlap. Forwarding those methods may yield up to 4% extra performance, although this heavily depends on setup and scenery.

Basic topology and system information (vendor ID, driver version and others) has been mostly tested with GPU Caps Viewer. The game Get Even, which verifies the driver version during launch, starts fine with this implementation.

Requirements

This implementation is supposed to be used on Linux using Wine or derivatives like Proton. It uses several DXVK extension points, thus using DXVK (D3D11 and DXGI) is a requirements. Using Wine's D3D11 or DXGI will fail. Usage of NVAPI-DXVK is not restricted to NVIDIA-GPU's, no specific NVIDIA hardware features are needed.

When available, NVAPI-DXVK uses NVIDIA's NVML management library to query temperature, utilization and others for NVIDIA GPU's. See wine-nvml how to add NVML support to Wine/Proton.

How to build

Like DXVK, this library is being built as a Windows DLL using MinGW, and has essentially the same build requirements. Using MinGW versions older than MinGW 7 might fail.

Run:

./package-release.sh master /your/path [--enable-tests]

Alternatively DXVK-Docker provides a way for a build setup using docker/podman. Pre-built binaries of release versions are available at https://github.com/jp7677/dxvk-nvapi/releases.

How to use

Copy nvapi64.dll/nvapi.dll into the system32/syswow64 folder of your x64/x86 Wine prefix.
Ensure that Wine uses the native version of nvapi64/nvapi, e.g. with WINEDLLOVERRIDES=nvapi64,nvapi=n.
Ensure that Wine uses DXVK's dxgi.dll, use it e.g. with WINEDLLOVERRIDES=dxgi=n.
Disable the nvapiHack in DXVK with dxgi.nvapiHack = False, see dxvk.conf.
Spoof an NVIDIA GPU when running a non-NVIDIA GPU with dxgi.customVendorId = 10de, see dxvk.conf.

Debugging

The following environment variables tweak DXVK-NVAPI's runtime behavior:

DXVK_NVAPI_DRIVER_VERSION lets you override the reported driver version. Valid values are numbers between 100 and 99999. Use e.g. DXVK_NVAPI_DRIVER_VERSION=47141 to report driver version 471.41.
DXVK_NVAPI_LOG_PATH enables file logging additionally to console output and sets the path where the log file dxvk-nvapi.log should be written to. Log statements are appended to an existing file. Please remove this file once in a while to prevent excessive grow.
DXVK_NVAPI_LOG_LEVEL set to none avoids log statements. Please fill an issue if this is needed to avoid certain log spam.

This project provides a test suite. Run the package script with --enable-tests (see above) to build nvapi64-tests.exe. Running the tests executable without arguments queries the local system and provides system information about visible GPU's:

DXVK_LOG_LEVEL=none DXVK_NVAPI_LOG_LEVEL=none WINEDEBUG=-all WINEDLLOVERRIDES=dxgi,nvapi64=n wine nvapi64-tests.exe

The test executable also runs on Windows against NVIDIA's nvapi64.dll. Ensure that DXVK-NVAPI's nvapi64.dllis not present in the current PATH for this scenario.

The actual unit tests can be run with nvapi64-tests.exe [@unit-tests] to validate DXVK-NVAPI's internal implementation.

References and inspirations

Many thanks to the corresponding authors!

Faalagorn / dxvk-nvapi