reproduce:
        git remote add agd5f https://gitlab.freedesktop.org/agd5f/linux.git
        git fetch --no-tags agd5f drm-next
        git checkout 82ffa89fa2803f9288163f538151a45581a88ca2
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # pip install -r Documentation/sphinx/requirements.txt
        make htmldocs