Whisper.cpp Vulkan on Arch: A Detective Story With No Crime

A six-week journey through source builds, CI pipelines, and one package pacman never mentioned. TL;DR: pacman -S whisper-cpp ggml-vulkan . That's it. That's the whole answer. Here's why it took me several weeks to find it. The setup I use whisper.cpp for local speech-to-text and as a part of my projects. I have a GPU utilization monitor permanently visible in my GNOME panel via the Vitals extension — so when whisper.cpp started detecting my GPU but running everything on CPU anyway, I noticed immediately. Went to fix it. What followed was several weeks of googling, building from source, writing a custom PKGBUILD, setting up CI, publishing an AUR-style repo — and eventually discovering that the actual fix is a single extra package that pacman never once mentioned to me. The investigation First thing I checked: is the official extra/whisper-cpp package compiled with Vulkan support? All search results said no — -DGGML_VULKAN is explicitly OFF, GPU code is absent from the binary. The app sees your GPU through vulkan-icd-loader but has no code to actually use it. That matched exactly what I was seeing. So the binary itself was the problem. At the time, a separate whisper-cpp-vulkan package had existed in the repos but kept appearing and disappearing — and right then it was gone from both extra and AUR. AUR pushes were also temporarily restricted due to a supply-chain incident. So the "just install the vulkan variant" path was closed, though it used to be available sometime. The obvious move: build from source with -DGGML_VULKAN=ON , package it up, done. I published whisper-cpp-vulkan-arch with a PKGBUILD and prebuilt binaries, wired up CI to track upstream releases automatically and rebuild correspondingly, and wrote a Reddit post explaining the situation. The post was dated August 13, 2026. The twist A few weeks later, someone commented on the post. They suggested installing ggml and vulkan-icd-loader . I started writing a detailed reply explaining why this was wrong: gg