ISTAT_RFO
if (bp->istat & ISTAT_RFO) { /* fast recovery, in ~20msec */
bp->istat &= ~ISTAT_RFO;
#define ISTAT_ERRORS (ISTAT_DSCE|ISTAT_DATAE|ISTAT_DPE|ISTAT_RDU|ISTAT_RFO|ISTAT_TFU)