diff --git a/drivers/scsi/qla2xxx/qla_attr.c b/drivers/scsi/qla2xxx/qla_attr.c
index fc25cd834668..47c9ecfc1d8f 100644
--- a/drivers/scsi/qla2xxx/qla_attr.c
+++ b/drivers/scsi/qla2xxx/qla_attr.c
@@ -319,6 +319,83 @@ qla2x00_state_show(struct class_device *cdev, char *buf)
 	return len;
 }
 
+static ssize_t
+qla2x00_zio_show(struct class_device *cdev, char *buf)
+{
+	scsi_qla_host_t *ha = to_qla_host(class_to_shost(cdev));
+	int len = 0;
+
+	switch (ha->zio_mode) {
+	case QLA_ZIO_MODE_5:
+		len += snprintf(buf + len, PAGE_SIZE-len, "Mode 5\n");
+		break;
+	case QLA_ZIO_MODE_6:
+		len += snprintf(buf + len, PAGE_SIZE-len, "Mode 6\n");
+		break;
+	case QLA_ZIO_DISABLED:
+		len += snprintf(buf + len, PAGE_SIZE-len, "Disabled\n");
+		break;
+	}
+	return len;
+}
+
+static ssize_t
+qla2x00_zio_store(struct class_device *cdev, const char *buf, size_t count)
+{
+	scsi_qla_host_t *ha = to_qla_host(class_to_shost(cdev));
+	int val = 0;
+	uint16_t zio_mode;
+
+	if (sscanf(buf, "%d", &val) != 1)
+		return -EINVAL;
+
+	switch (val) {
+	case 1:
+		zio_mode = QLA_ZIO_MODE_5;
+		break;
+	case 2:
+		zio_mode = QLA_ZIO_MODE_6;
+		break;
+	default:
+		zio_mode = QLA_ZIO_DISABLED;
+		break;
+	}
+
+	/* Update per-hba values and queue a reset. */
+	if (zio_mode != QLA_ZIO_DISABLED || ha->zio_mode != QLA_ZIO_DISABLED) {
+		ha->zio_mode = zio_mode;
+		set_bit(ISP_ABORT_NEEDED, &ha->dpc_flags);
+	}
+	return strlen(buf);
+}
+
+static ssize_t
+qla2x00_zio_timer_show(struct class_device *cdev, char *buf)
+{
+	scsi_qla_host_t *ha = to_qla_host(class_to_shost(cdev));
+
+	return snprintf(buf, PAGE_SIZE, "%d us\n", ha->zio_timer * 100);
+}
+
+static ssize_t
+qla2x00_zio_timer_store(struct class_device *cdev, const char *buf,
+    size_t count)
+{
+	scsi_qla_host_t *ha = to_qla_host(class_to_shost(cdev));
+	int val = 0;
+	uint16_t zio_timer;
+
+	if (sscanf(buf, "%d", &val) != 1)
+		return -EINVAL;
+	if (val > 25500 || val < 100)
+		return -ERANGE;
+
+	zio_timer = (uint16_t)(val / 100);
+	ha->zio_timer = zio_timer;
+
+	return strlen(buf);
+}
+
 static CLASS_DEVICE_ATTR(driver_version, S_IRUGO, qla2x00_drvr_version_show,
 	NULL);
 static CLASS_DEVICE_ATTR(fw_version, S_IRUGO, qla2x00_fw_version_show, NULL);
@@ -329,6 +406,10 @@ static CLASS_DEVICE_ATTR(model_name, S_IRUGO, qla2x00_model_name_show, NULL);
 static CLASS_DEVICE_ATTR(model_desc, S_IRUGO, qla2x00_model_desc_show, NULL);
 static CLASS_DEVICE_ATTR(pci_info, S_IRUGO, qla2x00_pci_info_show, NULL);
 static CLASS_DEVICE_ATTR(state, S_IRUGO, qla2x00_state_show, NULL);
+static CLASS_DEVICE_ATTR(zio, S_IRUGO | S_IWUSR, qla2x00_zio_show,
+    qla2x00_zio_store);
+static CLASS_DEVICE_ATTR(zio_timer, S_IRUGO | S_IWUSR, qla2x00_zio_timer_show,
+    qla2x00_zio_timer_store);
 
 struct class_device_attribute *qla2x00_host_attrs[] = {
 	&class_device_attr_driver_version,
@@ -340,6 +421,8 @@ struct class_device_attribute *qla2x00_host_attrs[] = {
 	&class_device_attr_model_desc,
 	&class_device_attr_pci_info,
 	&class_device_attr_state,
+	&class_device_attr_zio,
+	&class_device_attr_zio_timer,
 	NULL,
 };
 
diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
index b455c31405e4..522bb2d3f084 100644
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -823,6 +823,11 @@ typedef struct {
 #define PD_STATE_WAIT_PORT_LOGOUT_ACK		11
 
 
+#define QLA_ZIO_MODE_5		(BIT_2 | BIT_0)
+#define QLA_ZIO_MODE_6		(BIT_2 | BIT_1)
+#define QLA_ZIO_DISABLED	0
+#define QLA_ZIO_DEFAULT_TIMER	2
+
 /*
  * ISP Initialization Control Block.
  * Little endian except where noted.
@@ -2470,6 +2475,9 @@ typedef struct scsi_qla_host {
 	/* Needed for BEACON */
 	uint16_t	beacon_blink_led;
 	uint16_t	beacon_green_on;
+
+	uint16_t	zio_mode;
+	uint16_t	zio_timer;
 } scsi_qla_host_t;
 
 
diff --git a/drivers/scsi/qla2xxx/qla_gbl.h b/drivers/scsi/qla2xxx/qla_gbl.h
index e451941ad81d..c26b74da4054 100644
--- a/drivers/scsi/qla2xxx/qla_gbl.h
+++ b/drivers/scsi/qla2xxx/qla_gbl.h
@@ -76,8 +76,6 @@ extern char qla2x00_version_str[];
 extern int ql2xlogintimeout;
 extern int qlport_down_retry;
 extern int ql2xplogiabsentdevice;
-extern int ql2xenablezio;
-extern int ql2xintrdelaytimer;
 extern int ql2xloginretrycount;
 extern int ql2xfdmienable;
 
@@ -223,6 +221,7 @@ extern irqreturn_t qla2100_intr_handler(int, void *, struct pt_regs *);
 extern irqreturn_t qla2300_intr_handler(int, void *, struct pt_regs *);
 extern irqreturn_t qla24xx_intr_handler(int, void *, struct pt_regs *);
 extern void qla2x00_process_response_queue(struct scsi_qla_host *);
+extern void qla24xx_process_response_queue(struct scsi_qla_host *);
 
 /*
  * Global Function Prototypes in qla_sup.c source file.
diff --git a/drivers/scsi/qla2xxx/qla_init.c b/drivers/scsi/qla2xxx/qla_init.c
index 6fc8bbae9398..9e36fbd9245a 100644
--- a/drivers/scsi/qla2xxx/qla_init.c
+++ b/drivers/scsi/qla2xxx/qla_init.c
@@ -1372,7 +1372,6 @@ qla2x00_nvram_config(scsi_qla_host_t *ha)
 	nvram_t         *nv = (nvram_t *)ha->request_ring;
 	uint8_t         *ptr = (uint8_t *)ha->request_ring;
 	struct device_reg_2xxx __iomem *reg = &ha->iobase->isp;
-	uint8_t         timer_mode;
 
 	rval = QLA_SUCCESS;
 
@@ -1650,22 +1649,26 @@ qla2x00_nvram_config(scsi_qla_host_t *ha)
 
 		ha->flags.process_response_queue = 1;
 	} else {
-		/* Enable ZIO -- Support mode 5 only. */
-		timer_mode = icb->add_firmware_options[0] &
-		    (BIT_3 | BIT_2 | BIT_1 | BIT_0);
+		/* Enable ZIO. */
+		if (!ha->flags.init_done) {
+			ha->zio_mode = icb->add_firmware_options[0] &
+			    (BIT_3 | BIT_2 | BIT_1 | BIT_0);
+			ha->zio_timer = icb->interrupt_delay_timer ?
+			    icb->interrupt_delay_timer: 2;
+		}
 		icb->add_firmware_options[0] &=
 		    ~(BIT_3 | BIT_2 | BIT_1 | BIT_0);
-		if (ql2xenablezio)
-			timer_mode = BIT_2 | BIT_0;
-		if (timer_mode == (BIT_2 | BIT_0)) {
-			DEBUG2(printk("scsi(%ld): ZIO enabled; timer delay "
-			    "(%d).\n", ha->host_no, ql2xintrdelaytimer));
+		ha->flags.process_response_queue = 0;
+		if (ha->zio_mode != QLA_ZIO_DISABLED) {
+			DEBUG2(printk("scsi(%ld): ZIO mode %d enabled; timer "
+			    "delay (%d us).\n", ha->host_no, ha->zio_mode,
+			    ha->zio_timer * 100));
 			qla_printk(KERN_INFO, ha,
-			    "ZIO enabled; timer delay (%d).\n",
-			    ql2xintrdelaytimer);
+			    "ZIO mode %d enabled; timer delay (%d us).\n",
+			    ha->zio_mode, ha->zio_timer * 100);
 
-			icb->add_firmware_options[0] |= timer_mode;
-			icb->interrupt_delay_timer = ql2xintrdelaytimer;
+			icb->add_firmware_options[0] |= (uint8_t)ha->zio_mode;
+			icb->interrupt_delay_timer = (uint8_t)ha->zio_timer;
 			ha->flags.process_response_queue = 1;
 		}
 	}
@@ -3442,6 +3445,30 @@ qla24xx_nvram_config(scsi_qla_host_t *ha)
 	if (ql2xloginretrycount)
 		ha->login_retry_count = ql2xloginretrycount;
 
+	/* Enable ZIO. */
+	if (!ha->flags.init_done) {
+		ha->zio_mode = le32_to_cpu(icb->firmware_options_2) &
+		    (BIT_3 | BIT_2 | BIT_1 | BIT_0);
+		ha->zio_timer = le16_to_cpu(icb->interrupt_delay_timer) ?
+		    le16_to_cpu(icb->interrupt_delay_timer): 2;
+	}
+	icb->firmware_options_2 &= __constant_cpu_to_le32(
+	    ~(BIT_3 | BIT_2 | BIT_1 | BIT_0));
+	ha->flags.process_response_queue = 0;
+	if (ha->zio_mode != QLA_ZIO_DISABLED) {
+		DEBUG2(printk("scsi(%ld): ZIO mode %d enabled; timer delay "
+		    "(%d us).\n", ha->host_no, ha->zio_mode,
+		    ha->zio_timer * 100));
+		qla_printk(KERN_INFO, ha,
+		    "ZIO mode %d enabled; timer delay (%d us).\n",
+		    ha->zio_mode, ha->zio_timer * 100);
+
+		icb->firmware_options_2 |= cpu_to_le32(
+		    (uint32_t)ha->zio_mode);
+		icb->interrupt_delay_timer = cpu_to_le16(ha->zio_timer);
+		ha->flags.process_response_queue = 1;
+	}
+
 	if (rval) {
 		DEBUG2_3(printk(KERN_WARNING
 		    "scsi(%ld): NVRAM configuration failed!\n", ha->host_no));
diff --git a/drivers/scsi/qla2xxx/qla_iocb.c b/drivers/scsi/qla2xxx/qla_iocb.c
index 37f82e2cd7fb..d7355627f110 100644
--- a/drivers/scsi/qla2xxx/qla_iocb.c
+++ b/drivers/scsi/qla2xxx/qla_iocb.c
@@ -440,6 +440,11 @@ qla2x00_start_scsi(srb_t *sp)
 	WRT_REG_WORD(ISP_REQ_Q_IN(ha, reg), ha->req_ring_index);
 	RD_REG_WORD_RELAXED(ISP_REQ_Q_IN(ha, reg));	/* PCI Posting. */
 
+	/* Manage unprocessed RIO/ZIO commands in response queue. */
+	if (ha->flags.process_response_queue &&
+	    ha->response_ring_ptr->signature != RESPONSE_PROCESSED)
+		qla2x00_process_response_queue(ha);
+
 	spin_unlock_irqrestore(&ha->hardware_lock, flags);
 	return (QLA_SUCCESS);
 
@@ -877,6 +882,11 @@ qla24xx_start_scsi(srb_t *sp)
 	WRT_REG_DWORD(&reg->req_q_in, ha->req_ring_index);
 	RD_REG_DWORD_RELAXED(&reg->req_q_in);		/* PCI Posting. */
 
+	/* Manage unprocessed RIO/ZIO commands in response queue. */
+	if (ha->flags.process_response_queue &&
+	    ha->response_ring_ptr->signature != RESPONSE_PROCESSED)
+		qla24xx_process_response_queue(ha);
+
 	spin_unlock_irqrestore(&ha->hardware_lock, flags);
 	return QLA_SUCCESS;
 
diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index c255bb0268a9..cf6c6ce0b42b 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -21,13 +21,11 @@
 static void qla2x00_mbx_completion(scsi_qla_host_t *, uint16_t);
 static void qla2x00_async_event(scsi_qla_host_t *, uint16_t *);
 static void qla2x00_process_completed_request(struct scsi_qla_host *, uint32_t);
-void qla2x00_process_response_queue(struct scsi_qla_host *);
 static void qla2x00_status_entry(scsi_qla_host_t *, void *);
 static void qla2x00_status_cont_entry(scsi_qla_host_t *, sts_cont_entry_t *);
 static void qla2x00_error_entry(scsi_qla_host_t *, sts_entry_t *);
 static void qla2x00_ms_entry(scsi_qla_host_t *, ms_iocb_entry_t *);
 
-void qla24xx_process_response_queue(scsi_qla_host_t *);
 static void qla24xx_ms_entry(scsi_qla_host_t *, struct ct_entry_24xx *);
 
 /**
@@ -651,7 +649,10 @@ qla2x00_async_event(scsi_qla_host_t *ha, uint16_t *mb)
 		    "scsi(%ld): [R|Z]IO update completion.\n",
 		    ha->host_no));
 
-		qla2x00_process_response_queue(ha);
+		if (IS_QLA24XX(ha) || IS_QLA25XX(ha))
+			qla24xx_process_response_queue(ha);
+		else
+			qla2x00_process_response_queue(ha);
 		break;
 
 	case MBA_DISCARD_RND_FRAME:
diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index 7aec93f9d423..77054d7692c4 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -61,19 +61,6 @@ MODULE_PARM_DESC(ql2xplogiabsentdevice,
 		"a Fabric scan.  This is needed for several broken switches."
 		"Default is 0 - no PLOGI. 1 - perfom PLOGI.");
 
-int ql2xenablezio = 0;
-module_param(ql2xenablezio, int, S_IRUGO|S_IRUSR);
-MODULE_PARM_DESC(ql2xenablezio,
-		"Option to enable ZIO:If 1 then enable it otherwise"
-		" use the default set in the NVRAM."
-		" Default is 0 : disabled");
-
-int ql2xintrdelaytimer = 10;
-module_param(ql2xintrdelaytimer, int, S_IRUGO|S_IRUSR);
-MODULE_PARM_DESC(ql2xintrdelaytimer,
-		"ZIO: Waiting time for Firmware before it generates an "
-		"interrupt to the host to notify completion of request.");
-
 int ql2xloginretrycount = 0;
 module_param(ql2xloginretrycount, int, S_IRUGO|S_IRUSR);
 MODULE_PARM_DESC(ql2xloginretrycount,
@@ -400,16 +387,6 @@ qla2x00_queuecommand(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
 	if (rval != QLA_SUCCESS)
 		goto qc_host_busy_free_sp;
 
-	/* Manage unprocessed RIO/ZIO commands in response queue. */
-	if (ha->flags.online && ha->flags.process_response_queue &&
-	    ha->response_ring_ptr->signature != RESPONSE_PROCESSED) {
-		unsigned long flags;
-
-		spin_lock_irqsave(&ha->hardware_lock, flags);
-		qla2x00_process_response_queue(ha);
-		spin_unlock_irqrestore(&ha->hardware_lock, flags);
-	}
-
 	spin_lock_irq(ha->host->host_lock);
 
 	return 0;