reproduce:
        # https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git/commit/?id=59444a29dbfd44718fef15083aa339c2c8b579b5
        git remote add tiwai-sound https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git
        git fetch --no-tags tiwai-sound test/snd_ctl_remove-lock-fix
        git checkout 59444a29dbfd44718fef15083aa339c2c8b579b5
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        make htmldocs