Valve-funded engineering from Collabora brings AMD’s open-source Mesa Vulkan driver natively to Windows, running titles like Counter-Strike 2 without Linux subsystem layers.
On 28 July 2026, software consultancy Collabora detailed Valve’s sponsorship to port RADV, the community-maintained open-source Mesa Vulkan driver for AMD graphics cards, natively to Microsoft Windows. Building on Faith Ekstrand’s initial research presented at XDC 2024, the project eliminated Windows Subsystem for Linux (WSL) dependencies, allowing games like Counter-Strike 2 to run natively via Vulkan.
Technically, RADV operates as an open-source User-Mode Driver (UMD) on Windows via WDDM2 integration. Because porting the Linux kernel driver (amdgpu) was out of scope, RADV interfaces directly with AMD’s proprietary Windows kernel driver. Engineers reverse-engineered undocumented kernel data structures using custom tools, including wddm2-pdd-re and a specialised WDDM2 logging layer, to inspect command streams and registers.
The project resolved GPU hangs across hardware generations, fixed MSVC compiler issues (such as signed 32-bit enum handling), and confirmed vendor-specific D3DKMTEscape calls can be safely bypassed in single-GPU setups. Feature support now spans sparse bindings, tessellation, task shaders, GPU property detection, and improved synchronisation.
Long-term production stability remains constrained by AMD’s proprietary kernel driver. Because its undocumented interfaces can change without warning, future driver updates risk breaking RADV. Collabora noted that long-term viability requires AMD to provide a documented kernel interface or developers to maintain a compatibility layer.
