Blumenkrantz Flushes 17.1k Lines Of Old Mesa Code

Well known Zink developer Mike Blumenkrantz, working for Valve on improving Mesa's OpenGL-on-Vulkan driver, has kicked off October by removing a lot of old Mesa code.

With a merge request now merged for Mesa 22.3-devel, some 17.1k lines of old Mesa code have been removed. In particular, Gallium3D's old XvMC front-end has been removed. X-Video Motion Compensation (XvMC) as the X.Org Server extension allowing some video offload work to happen on the GPU has long been obsolete. XvMC was of some use nearly two decades ago but for the past number of years VA-API and VDPAU APIs have been much more common and far more useful than the limited functionality provided by XvMC. Thus it's good to see the XvMC front-end finally nuked as XvMC was only useful anyhow for MPEG-1/MPEG-2 video content and accelerated a limited set of processes. Removing the Gallium3D XvMC code was some 3.5k lines of code.

Rbug was also removed as another 7k lines of obsolete code. Gallium3D's Rbug was intended as a remote debugger pipe driver. Rbug was developed by Tungsten Graphics / VMware to help with remote debugging of graphics issues. This remote debugging for Gallium3D though has been largely untouched for a decade and even rbug-gui as the remote debugging interface hasn't seen any code commits since 2014.

Gallium3D GRAW was also removed as another 6.5k lines of unmaintained code. Gallium3D GRAW was intended as a raw Gallium interface without a front-end.

Besides removing 17k+ lines of unmaintained code, the other benefit of clearing out Rbug / GRAW / XvMC is that it will allow the Mesa developers to more easily make Gallium3D interface changes without having to update these unused components or worrying about breaking this otherwise unused functionality.