diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index f1c3c4946637..1ca9753cb734 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -421,11 +421,13 @@ static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 					       STp->cln_sense_mask) != 0);
 	}
 	if (cmdstatp->have_sense &&
-	    cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
-		STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
+	    cmdstatp->sense_hdr.sense_code == CLEANING_REQUESTED)
+		STp->cleaning_req = 1;
 	if (cmdstatp->have_sense && scode == UNIT_ATTENTION &&
-		cmdstatp->sense_hdr.asc == 0x29 && !STp->pos_unknown) {
-		STp->pos_unknown = 1; /* ASC => power on / reset */
+	    scsi_sense_asc(&cmdstatp->sense_hdr) ==
+	    ASC_POWER_ON_RESET_OR_BUS_DEVICE_RESET_OCCURRED &&
+	    !STp->pos_unknown) {
+		STp->pos_unknown = 1;
 		st_printk(KERN_WARNING, STp, "Power on/reset recognized.");
 	}
 
@@ -1003,7 +1005,8 @@ static int test_ready(struct scsi_tape *STp, int do_wait)
 			scode = cmdstatp->sense_hdr.sense_key;
 
 			if (scode == UNIT_ATTENTION) { /* New media? */
-				if (cmdstatp->sense_hdr.asc == 0x28) { /* New media */
+				if (scsi_sense_asc(&cmdstatp->sense_hdr) ==
+				    ASC_NOT_READY_TO_READY_CHANGE_MEDIUM_MAY_HAVE_CHANGED) {
 					new_session = 1;
 					DEBC_printk(STp, "New tape session.");
 				}
@@ -1026,14 +1029,13 @@ static int test_ready(struct scsi_tape *STp, int do_wait)
 					waits++;
 					continue;
 				}
-				else {
-					if ((STp->device)->scsi_level >= SCSI_2 &&
-					    cmdstatp->sense_hdr.asc == 0x3a)	/* Check ASC */
-						retval = CHKRES_NO_TAPE;
-					else
-						retval = CHKRES_NOT_READY;
-					break;
-				}
+				if ((STp->device)->scsi_level >= SCSI_2 &&
+				    scsi_sense_asc(&cmdstatp->sense_hdr) ==
+				    ASC_MEDIUM_NOT_PRESENT)
+					retval = CHKRES_NO_TAPE;
+				else
+					retval = CHKRES_NOT_READY;
+				break;
 			}
 		}
 
@@ -3105,9 +3107,10 @@ static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned lon
 			   cmd_in == MTSETDRVBUFFER ||
 			   cmd_in == SET_DENS_AND_BLK) {
 			if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
-				cmdstatp->sense_hdr.asc == 0x24 &&
-				(STp->device)->scsi_level <= SCSI_2 &&
-				!(STp->use_pf & PF_TESTED)) {
+			    scsi_sense_asc(&cmdstatp->sense_hdr) ==
+			    ASC_INVALID_FIELD_IN_CDB &&
+			    (STp->device)->scsi_level <= SCSI_2 &&
+			    !(STp->use_pf & PF_TESTED)) {
 				/* Try the other possible state of Page Format if not
 				   already tried */
 				STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;