reproduce:
        git remote add drm-xe https://gitlab.freedesktop.org/drm/xe/kernel.git
        git fetch --no-tags drm-xe drm-xe-next
        git checkout 2270bd7124f4d25497d58c293cd40ea014ddaf01
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # pip install -r Documentation/sphinx/requirements.txt
        make htmldocs