diff --git a/libfprint/fp_internal.h b/libfprint/fp_internal.h
index 197dc95..f7b2bc8 100644
--- a/libfprint/fp_internal.h
+++ b/libfprint/fp_internal.h
@@ -369,7 +369,6 @@ struct fpi_ssm *fpi_ssm_new(struct fp_dev *dev, ssm_handler_fn handler,
 	int nr_states);
 void fpi_ssm_free(struct fpi_ssm *machine);
 void fpi_ssm_start(struct fpi_ssm *machine, ssm_completed_fn callback);
-void fpi_ssm_start_subsm(struct fpi_ssm *parent, struct fpi_ssm *child);
 
 /* for drivers */
 void fpi_ssm_next_state(struct fpi_ssm *machine);