reproduce:
        # https://git.kernel.org/pub/scm/linux/kernel/git/superm1/linux.git/commit/?id=4dbf62273708e62ea3d1532671b4e5c26f722b8b
        git remote add amd-pstate https://git.kernel.org/pub/scm/linux/kernel/git/superm1/linux.git
        git fetch --no-tags amd-pstate superm1/backlight-property-v5
        git checkout 4dbf62273708e62ea3d1532671b4e5c26f722b8b
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # pip install -r Documentation/sphinx/requirements.txt
        make htmldocs