reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply.git/commit/?id=ea4367c40c79a5f16cb0de8a94a6b72697d37f06
        git remote add sre-power-supply https://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply.git
        git fetch --no-tags sre-power-supply for-next
        git checkout ea4367c40c79a5f16cb0de8a94a6b72697d37f06
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=um olddefconfig
        make W=1 O=build_dir ARCH=um SHELL=/bin/bash drivers/power/