reproduce (this is a W=1 build):
        # https://github.com/l1k/linux/commit/248969a7aec19ca7f68ecb2a118ffee1a5eb8e9c
        git remote add l1k https://github.com/l1k/linux
        git fetch --no-tags l1k broadcom
        git checkout 248969a7aec19ca7f68ecb2a118ffee1a5eb8e9c

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/pci/