reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine.git/commit/?id=68811c928f88828f188656dd3c9c184eeec2ce86
        git remote add vkoul-dmaengine https://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine.git
        git fetch --no-tags vkoul-dmaengine next
        git checkout 68811c928f88828f188656dd3c9c184eeec2ce86
        # save the config file
        make W=1 ARCH=i386 olddefconfig
        make W=1 ARCH=i386