*** /usr/src/sys/dev/sio/sio.c  Wed Apr 15 03:14:26 2009
--- sio.c       Tue Dec 15 20:31:48 2009
***************
*** 2077,2086 ****
--- 2077,2087 ----
  
        com = tp->t_sc;
        if (com == NULL || com->gone)
                return;
        mtx_lock_spin(&sio_lock);
+         DELAY(250000);
        if (rw & FWRITE) {
                if (com->hasfifo)
  #ifdef COM_ESP
                    /* XXX avoid h/w bug. */
                    if (!com->esp)