reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=ba2db93cf3d569a4525a02cd0ed5ec5f979e3afd
        git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
        git fetch --no-tags linux-next master
        git checkout ba2db93cf3d569a4525a02cd0ed5ec5f979e3afd

        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # apt-get install sparse
        # sparse: v0.6.5-rc1

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.5.0 ~/lkp-tests/kbuild/make.cross W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=openrisc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.5.0 ~/lkp-tests/kbuild/make.cross W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=openrisc SHELL=/bin/bash drivers/gpu/drm/bridge/