diff -urNp linux-5420/drivers/scsi/sym53c8xx.c linux-5430/drivers/scsi/sym53c8xx.c
--- linux-5420/drivers/scsi/sym53c8xx.c
+++ linux-5430/drivers/scsi/sym53c8xx.c
@@ -11981,6 +11981,19 @@ static lcb_p ncr_setup_lcb (ncb_p np, u_
 		inq_byte7 |= INQ7_SYNC;
 
 	/*
+	**	Don't do PPR negotiations on SCSI-2 devices unless
+	**	they set the DT bit (0x04) in byte 57 of the INQUIRY
+	**	return data.
+	*/
+	if (((inq_data[2] & 0x07) < 3) && (inq_data[4] < 53 ||
+					   !(inq_data[56] & 0x04))) {
+		if (tp->minsync < 10)
+			tp->minsync = 10;
+		if (tp->usrsync < 10)
+			tp->usrsync = 10;
+	}
+
+	/*
 	**	Prepare negotiation if SIP capabilities have changed.
 	*/
 	tp->inq_done = 1;