reproduce:
        # apt-get install sparse
        # sparse version: v0.6.4-66-g0196afe1
        # https://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394.git/commit/?id=e406eaaef9d5c80a3b7651fadc1a048659f18029
        git remote add ieee1394-linux1394 https://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394.git
        git fetch --no-tags ieee1394-linux1394 topic/packet-header-serdes
        git checkout e406eaaef9d5c80a3b7651fadc1a048659f18029
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=i386 olddefconfig
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=i386 SHELL=/bin/bash drivers/firewire/