Mesa Drops Its Poorly Maintained & Rarely Used Direct3D 10 User-Mode Driver

Back in 2021 the Direct3D 10 User-Mode Driver "d3d10umd" was introduced as a new Gallium3D state tracker to work as a Windows WDDM UMD driver similar to Windows WARP while leveraging LLVMpipe for better performance. Now five years later the poorly maintained code is removed from the Mesa codebase. This d3d10umd code is similar to Windows' WARP rasterizer but leveraging Mesa/s LLVMpipe in its place. VMware worked on this as part of their virtualization deliverables for use on Microsoft Windows and didn't work under the likes of Wine. The only other apparent use of it was within some VirGL VM uses on Windows. The 12.7k lines of code making up this driver though are now removed from Mesa as of the Mesa 26.3 release due out later this quarter. The motivation for getting this seldom talked about driver code removed from Mesa came down to it being one of the few users left emitting TGSI as the original Gallium3D intermediate representation (IR) rather than the preferred NIR format. Even when the driver was merged back in 2021, it was still targeting the old TGSI as a known shortcoming of the implementation. With Mesa developers working to eliminate TGSI from the stack, the d3d10umd driver is removed for not supporting NIR and no apparent plans to. With no objections including from Jose Fonseca who worked on this driver at VMware, now owned by Broadcom, the driver was removed this week per this merge request.