DEVI_BUSY
{ "BUSY", DEVI_BUSY, DEVI_BUSY },
devi->devi_flags |= DEVI_BUSY;
devi->devi_flags &= ~DEVI_BUSY;
devi->devi_flags &= ~DEVI_BUSY;
devi->devi_flags |= DEVI_BUSY;
#define DEVI_BUSY_CHANGING(dip) (DEVI(dip)->devi_flags & DEVI_BUSY)