diff --git a/drivers/scsi/mpi3mr/mpi3mr.h b/drivers/scsi/mpi3mr/mpi3mr.h
index 24b65bb..2602957 100644
--- a/drivers/scsi/mpi3mr/mpi3mr.h
+++ b/drivers/scsi/mpi3mr/mpi3mr.h
@@ -96,7 +96,11 @@ extern int prot_mask;
 #define MPI3MR_HOSTTAG_DEVRMCMD_MAX	(MPI3MR_HOSTTAG_DEVRMCMD_MIN + \
 						MPI3MR_NUM_DEVRMCMD - 1)
 
-#define MPI3MR_INTERNAL_CMDS_RESVD     MPI3MR_HOSTTAG_DEVRMCMD_MAX
+#define MPI3MR_INTERNAL_CMDS_RESVD	MPI3MR_HOSTTAG_DEVRMCMD_MAX
+#define MPI3MR_NUM_EVTACKCMD		4
+#define MPI3MR_HOSTTAG_EVTACKCMD_MIN	(MPI3MR_HOSTTAG_DEVRMCMD_MAX + 1)
+#define MPI3MR_HOSTTAG_EVTACKCMD_MAX	(MPI3MR_HOSTTAG_EVTACKCMD_MIN + \
+					MPI3MR_NUM_EVTACKCMD - 1)
 
 /* Reduced resource count definition for crash kernel */
 #define MPI3MR_HOST_IOS_KDUMP		128
@@ -674,11 +678,15 @@ struct scmd_priv {
  * @chain_buf_lock: Chain buffer list lock
  * @host_tm_cmds: Command tracker for task management commands
  * @dev_rmhs_cmds: Command tracker for device removal commands
+ * @evtack_cmds: Command tracker for event ack commands
  * @devrem_bitmap_sz: Device removal bitmap size
  * @devrem_bitmap: Device removal bitmap
  * @dev_handle_bitmap_sz: Device handle bitmap size
  * @removepend_bitmap: Remove pending bitmap
  * @delayed_rmhs_list: Delayed device removal list
+ * @evtack_cmds_bitmap_sz: Event Ack bitmap size
+ * @evtack_cmds_bitmap: Event Ack bitmap
+ * @delayed_evtack_cmds_list: Delayed event acknowledgment list
  * @ts_update_counter: Timestamp update counter
  * @reset_in_progress: Reset in progress flag
  * @unrecoverable: Controller unrecoverable flag
@@ -800,11 +808,15 @@ struct mpi3mr_ioc {
 
 	struct mpi3mr_drv_cmd host_tm_cmds;
 	struct mpi3mr_drv_cmd dev_rmhs_cmds[MPI3MR_NUM_DEVRMCMD];
+	struct mpi3mr_drv_cmd evtack_cmds[MPI3MR_NUM_EVTACKCMD];
 	u16 devrem_bitmap_sz;
 	void *devrem_bitmap;
 	u16 dev_handle_bitmap_sz;
 	void *removepend_bitmap;
 	struct list_head delayed_rmhs_list;
+	u16 evtack_cmds_bitmap_sz;
+	void *evtack_cmds_bitmap;
+	struct list_head delayed_evtack_cmds_list;
 
 	u32 ts_update_counter;
 	u8 reset_in_progress;
@@ -862,6 +874,18 @@ struct delayed_dev_rmhs_node {
 	u8 iou_rc;
 };
 
+/**
+ * struct delayed_evt_ack_node - Delayed event ack node
+ * @list: list head
+ * @event: MPI3 event ID
+ * @event_ctx: event context
+ */
+struct delayed_evt_ack_node {
+	struct list_head list;
+	u8 event;
+	u32 event_ctx;
+};
+
 int mpi3mr_setup_resources(struct mpi3mr_ioc *mrioc);
 void mpi3mr_cleanup_resources(struct mpi3mr_ioc *mrioc);
 int mpi3mr_init_ioc(struct mpi3mr_ioc *mrioc);
@@ -898,7 +922,7 @@ void mpi3mr_ioc_disable_intr(struct mpi3mr_ioc *mrioc);
 void mpi3mr_ioc_enable_intr(struct mpi3mr_ioc *mrioc);
 
 enum mpi3mr_iocstate mpi3mr_get_iocstate(struct mpi3mr_ioc *mrioc);
-int mpi3mr_send_event_ack(struct mpi3mr_ioc *mrioc, u8 event,
+int mpi3mr_process_event_ack(struct mpi3mr_ioc *mrioc, u8 event,
 			  u32 event_ctx);
 
 void mpi3mr_wait_for_host_io(struct mpi3mr_ioc *mrioc, u32 timeout);
@@ -906,7 +930,7 @@ void mpi3mr_cleanup_fwevt_list(struct mpi3mr_ioc *mrioc);
 void mpi3mr_flush_host_io(struct mpi3mr_ioc *mrioc);
 void mpi3mr_invalidate_devhandles(struct mpi3mr_ioc *mrioc);
 void mpi3mr_rfresh_tgtdevs(struct mpi3mr_ioc *mrioc);
-void mpi3mr_flush_delayed_rmhs_list(struct mpi3mr_ioc *mrioc);
+void mpi3mr_flush_delayed_cmd_lists(struct mpi3mr_ioc *mrioc);
 void mpi3mr_check_rh_fault_ioc(struct mpi3mr_ioc *mrioc, u32 reason_code);
 void mpi3mr_print_fault_info(struct mpi3mr_ioc *mrioc);
 void mpi3mr_check_rh_fault_ioc(struct mpi3mr_ioc *mrioc, u32 reason_code);
diff --git a/drivers/scsi/mpi3mr/mpi3mr_fw.c b/drivers/scsi/mpi3mr/mpi3mr_fw.c
index 4050195..b513dca 100644
--- a/drivers/scsi/mpi3mr/mpi3mr_fw.c
+++ b/drivers/scsi/mpi3mr/mpi3mr_fw.c
@@ -312,6 +312,12 @@ mpi3mr_get_drv_cmd(struct mpi3mr_ioc *mrioc, u16 host_tag,
 		return &mrioc->dev_rmhs_cmds[idx];
 	}
 
+	if (host_tag >= MPI3MR_HOSTTAG_EVTACKCMD_MIN &&
+	    host_tag <= MPI3MR_HOSTTAG_EVTACKCMD_MAX) {
+		idx = host_tag - MPI3MR_HOSTTAG_EVTACKCMD_MIN;
+		return &mrioc->evtack_cmds[idx];
+	}
+
 	return NULL;
 }
 
@@ -2691,6 +2697,13 @@ static int mpi3mr_alloc_reply_sense_bufs(struct mpi3mr_ioc *mrioc)
 			goto out_failed;
 	}
 
+	for (i = 0; i < MPI3MR_NUM_EVTACKCMD; i++) {
+		mrioc->evtack_cmds[i].reply = kzalloc(mrioc->reply_sz,
+		    GFP_KERNEL);
+		if (!mrioc->evtack_cmds[i].reply)
+			goto out_failed;
+	}
+
 	mrioc->host_tm_cmds.reply = kzalloc(mrioc->reply_sz, GFP_KERNEL);
 	if (!mrioc->host_tm_cmds.reply)
 		goto out_failed;
@@ -2711,6 +2724,14 @@ static int mpi3mr_alloc_reply_sense_bufs(struct mpi3mr_ioc *mrioc)
 	if (!mrioc->devrem_bitmap)
 		goto out_failed;
 
+	mrioc->evtack_cmds_bitmap_sz = MPI3MR_NUM_EVTACKCMD / 8;
+	if (MPI3MR_NUM_EVTACKCMD % 8)
+		mrioc->evtack_cmds_bitmap_sz++;
+	mrioc->evtack_cmds_bitmap = kzalloc(mrioc->evtack_cmds_bitmap_sz,
+	    GFP_KERNEL);
+	if (!mrioc->evtack_cmds_bitmap)
+		goto out_failed;
+
 	mrioc->num_reply_bufs = mrioc->facts.max_reqs + MPI3MR_NUM_EVT_REPLIES;
 	mrioc->reply_free_qsz = mrioc->num_reply_bufs + 1;
 	mrioc->num_sense_bufs = mrioc->facts.max_reqs / MPI3MR_SENSEBUF_FACTOR;
@@ -3030,17 +3051,17 @@ out:
 }
 
 /**
- * mpi3mr_send_event_ack - Send event acknowledgment
+ * mpi3mr_process_event_ack - Process event acknowledgment
  * @mrioc: Adapter instance reference
  * @event: MPI3 event ID
- * @event_ctx: Event context
+ * @event_ctx: event context
  *
  * Send event acknowledgment through admin queue and wait for
  * it to complete.
  *
  * Return: 0 on success, non-zero on failures.
  */
-int mpi3mr_send_event_ack(struct mpi3mr_ioc *mrioc, u8 event,
+int mpi3mr_process_event_ack(struct mpi3mr_ioc *mrioc, u8 event,
 	u32 event_ctx)
 {
 	struct mpi3_event_ack_request evtack_req;
@@ -3803,8 +3824,13 @@ void mpi3mr_memset_buffers(struct mpi3mr_ioc *mrioc)
 		for (i = 0; i < MPI3MR_NUM_DEVRMCMD; i++)
 			memset(mrioc->dev_rmhs_cmds[i].reply, 0,
 			    sizeof(*mrioc->dev_rmhs_cmds[i].reply));
+		for (i = 0; i < MPI3MR_NUM_EVTACKCMD; i++)
+			memset(mrioc->evtack_cmds[i].reply, 0,
+			    sizeof(*mrioc->evtack_cmds[i].reply));
 		memset(mrioc->removepend_bitmap, 0, mrioc->dev_handle_bitmap_sz);
 		memset(mrioc->devrem_bitmap, 0, mrioc->devrem_bitmap_sz);
+		memset(mrioc->evtack_cmds_bitmap, 0,
+		    mrioc->evtack_cmds_bitmap_sz);
 	}
 
 	for (i = 0; i < mrioc->num_queues; i++) {
@@ -3898,12 +3924,20 @@ void mpi3mr_free_mem(struct mpi3mr_ioc *mrioc)
 	kfree(mrioc->host_tm_cmds.reply);
 	mrioc->host_tm_cmds.reply = NULL;
 
+	for (i = 0; i < MPI3MR_NUM_EVTACKCMD; i++) {
+		kfree(mrioc->evtack_cmds[i].reply);
+		mrioc->evtack_cmds[i].reply = NULL;
+	}
+
 	kfree(mrioc->removepend_bitmap);
 	mrioc->removepend_bitmap = NULL;
 
 	kfree(mrioc->devrem_bitmap);
 	mrioc->devrem_bitmap = NULL;
 
+	kfree(mrioc->evtack_cmds_bitmap);
+	mrioc->evtack_cmds_bitmap = NULL;
+
 	kfree(mrioc->chain_bitmap);
 	mrioc->chain_bitmap = NULL;
 
@@ -4079,6 +4113,11 @@ static void mpi3mr_flush_drv_cmds(struct mpi3mr_ioc *mrioc)
 		cmdptr = &mrioc->dev_rmhs_cmds[i];
 		mpi3mr_drv_cmd_comp_reset(mrioc, cmdptr);
 	}
+
+	for (i = 0; i < MPI3MR_NUM_EVTACKCMD; i++) {
+		cmdptr = &mrioc->evtack_cmds[i];
+		mpi3mr_drv_cmd_comp_reset(mrioc, cmdptr);
+	}
 }
 
 /**
@@ -4176,10 +4215,11 @@ int mpi3mr_soft_reset_handler(struct mpi3mr_ioc *mrioc,
 		goto out;
 	}
 
-	mpi3mr_flush_delayed_rmhs_list(mrioc);
+	mpi3mr_flush_delayed_cmd_lists(mrioc);
 	mpi3mr_flush_drv_cmds(mrioc);
 	memset(mrioc->devrem_bitmap, 0, mrioc->devrem_bitmap_sz);
 	memset(mrioc->removepend_bitmap, 0, mrioc->dev_handle_bitmap_sz);
+	memset(mrioc->evtack_cmds_bitmap, 0, mrioc->evtack_cmds_bitmap_sz);
 	mpi3mr_cleanup_fwevt_list(mrioc);
 	mpi3mr_flush_host_io(mrioc);
 	mpi3mr_invalidate_devhandles(mrioc);
diff --git a/drivers/scsi/mpi3mr/mpi3mr_os.c b/drivers/scsi/mpi3mr/mpi3mr_os.c
index 38e1043..728d6ce 100644
--- a/drivers/scsi/mpi3mr/mpi3mr_os.c
+++ b/drivers/scsi/mpi3mr/mpi3mr_os.c
@@ -34,6 +34,9 @@ MODULE_PARM_DESC(logging_level,
 	" bits for enabling additional logging info (default=0)");
 
 /* Forward declarations*/
+static void mpi3mr_send_event_ack(struct mpi3mr_ioc *mrioc, u8 event,
+	struct mpi3mr_drv_cmd *cmdparam, u32 event_ctx);
+
 /**
  * mpi3mr_host_tag_for_scmd - Get host tag for a scmd
  * @mrioc: Adapter instance reference
@@ -1336,7 +1339,7 @@ static void mpi3mr_fwevt_bh(struct mpi3mr_ioc *mrioc,
 
 evt_ack:
 	if (fwevt->send_ack)
-		mpi3mr_send_event_ack(mrioc, fwevt->event_id,
+		mpi3mr_process_event_ack(mrioc, fwevt->event_id,
 		    fwevt->evt_ctx);
 out:
 	/* Put fwevt reference count to neutralize kref_init increment */
@@ -1400,24 +1403,33 @@ static int mpi3mr_create_tgtdev(struct mpi3mr_ioc *mrioc,
 }
 
 /**
- * mpi3mr_flush_delayed_rmhs_list - Flush pending commands
+ * mpi3mr_flush_delayed_cmd_lists - Flush pending commands
  * @mrioc: Adapter instance reference
  *
- * Flush pending commands in the delayed removal handshake list
- * due to a controller reset or driver removal as a cleanup.
+ * Flush pending commands in the delayed lists due to a
+ * controller reset or driver removal as a cleanup.
  *
  * Return: Nothing
  */
-void mpi3mr_flush_delayed_rmhs_list(struct mpi3mr_ioc *mrioc)
+void mpi3mr_flush_delayed_cmd_lists(struct mpi3mr_ioc *mrioc)
 {
 	struct delayed_dev_rmhs_node *_rmhs_node;
+	struct delayed_evt_ack_node *_evtack_node;
 
+	dprint_reset(mrioc, "flushing delayed dev_remove_hs commands\n");
 	while (!list_empty(&mrioc->delayed_rmhs_list)) {
 		_rmhs_node = list_entry(mrioc->delayed_rmhs_list.next,
 		    struct delayed_dev_rmhs_node, list);
 		list_del(&_rmhs_node->list);
 		kfree(_rmhs_node);
 	}
+	dprint_reset(mrioc, "flushing delayed event ack commands\n");
+	while (!list_empty(&mrioc->delayed_evtack_cmds_list)) {
+		_evtack_node = list_entry(mrioc->delayed_evtack_cmds_list.next,
+		    struct delayed_evt_ack_node, list);
+		list_del(&_evtack_node->list);
+		kfree(_evtack_node);
+	}
 }
 
 /**
@@ -1633,6 +1645,141 @@ out_failed:
 	clear_bit(cmd_idx, mrioc->devrem_bitmap);
 }
 
+/**
+ * mpi3mr_complete_evt_ack - event ack request completion
+ * @mrioc: Adapter instance reference
+ * @drv_cmd: Internal command tracker
+ *
+ * This is the completion handler for non blocking event
+ * acknowledgment sent to the firmware and this will issue any
+ * pending event acknowledgment request.
+ *
+ * Return: Nothing
+ */
+static void mpi3mr_complete_evt_ack(struct mpi3mr_ioc *mrioc,
+	struct mpi3mr_drv_cmd *drv_cmd)
+{
+	u16 cmd_idx = drv_cmd->host_tag - MPI3MR_HOSTTAG_EVTACKCMD_MIN;
+	struct delayed_evt_ack_node *delayed_evtack = NULL;
+
+	if (drv_cmd->ioc_status != MPI3_IOCSTATUS_SUCCESS) {
+		dprint_event_th(mrioc,
+		    "immediate event ack failed with ioc_status(0x%04x) log_info(0x%08x)\n",
+		    (drv_cmd->ioc_status & MPI3_IOCSTATUS_STATUS_MASK),
+		    drv_cmd->ioc_loginfo);
+	}
+
+	if (!list_empty(&mrioc->delayed_evtack_cmds_list)) {
+		delayed_evtack =
+			list_entry(mrioc->delayed_evtack_cmds_list.next,
+			    struct delayed_evt_ack_node, list);
+		mpi3mr_send_event_ack(mrioc, delayed_evtack->event, drv_cmd,
+		    delayed_evtack->event_ctx);
+		list_del(&delayed_evtack->list);
+		kfree(delayed_evtack);
+		return;
+	}
+	drv_cmd->state = MPI3MR_CMD_NOTUSED;
+	drv_cmd->callback = NULL;
+	clear_bit(cmd_idx, mrioc->evtack_cmds_bitmap);
+}
+
+/**
+ * mpi3mr_send_event_ack - Issue event acknwoledgment request
+ * @mrioc: Adapter instance reference
+ * @event: MPI3 event id
+ * @cmdparam: Internal command tracker
+ * @event_ctx: event context
+ *
+ * Issues event acknowledgment request to the firmware if there
+ * is a free command to send the event ack else it to a pend
+ * list so that it will be processed on a completion of a prior
+ * event acknowledgment .
+ *
+ * Return: Nothing
+ */
+static void mpi3mr_send_event_ack(struct mpi3mr_ioc *mrioc, u8 event,
+	struct mpi3mr_drv_cmd *cmdparam, u32 event_ctx)
+{
+	struct mpi3_event_ack_request evtack_req;
+	int retval = 0;
+	u8 retrycount = 5;
+	u16 cmd_idx = MPI3MR_NUM_EVTACKCMD;
+	struct mpi3mr_drv_cmd *drv_cmd = cmdparam;
+	struct delayed_evt_ack_node *delayed_evtack = NULL;
+
+	if (drv_cmd) {
+		dprint_event_th(mrioc,
+		    "sending delayed event ack in the top half for event(0x%02x), event_ctx(0x%08x)\n",
+		    event, event_ctx);
+		goto issue_cmd;
+	}
+	dprint_event_th(mrioc,
+	    "sending event ack in the top half for event(0x%02x), event_ctx(0x%08x)\n",
+	    event, event_ctx);
+	do {
+		cmd_idx = find_first_zero_bit(mrioc->evtack_cmds_bitmap,
+		    MPI3MR_NUM_EVTACKCMD);
+		if (cmd_idx < MPI3MR_NUM_EVTACKCMD) {
+			if (!test_and_set_bit(cmd_idx,
+			    mrioc->evtack_cmds_bitmap))
+				break;
+			cmd_idx = MPI3MR_NUM_EVTACKCMD;
+		}
+	} while (retrycount--);
+
+	if (cmd_idx >= MPI3MR_NUM_EVTACKCMD) {
+		delayed_evtack = kzalloc(sizeof(*delayed_evtack),
+		    GFP_ATOMIC);
+		if (!delayed_evtack)
+			return;
+		INIT_LIST_HEAD(&delayed_evtack->list);
+		delayed_evtack->event = event;
+		delayed_evtack->event_ctx = event_ctx;
+		list_add_tail(&delayed_evtack->list,
+		    &mrioc->delayed_evtack_cmds_list);
+		dprint_event_th(mrioc,
+		    "event ack in the top half for event(0x%02x), event_ctx(0x%08x) is postponed\n",
+		    event, event_ctx);
+		return;
+	}
+	drv_cmd = &mrioc->evtack_cmds[cmd_idx];
+
+issue_cmd:
+	cmd_idx = drv_cmd->host_tag - MPI3MR_HOSTTAG_EVTACKCMD_MIN;
+
+	memset(&evtack_req, 0, sizeof(evtack_req));
+	if (drv_cmd->state & MPI3MR_CMD_PENDING) {
+		dprint_event_th(mrioc,
+		    "sending event ack failed due to command in use\n");
+		goto out;
+	}
+	drv_cmd->state = MPI3MR_CMD_PENDING;
+	drv_cmd->is_waiting = 0;
+	drv_cmd->callback = mpi3mr_complete_evt_ack;
+	evtack_req.host_tag = cpu_to_le16(drv_cmd->host_tag);
+	evtack_req.function = MPI3_FUNCTION_EVENT_ACK;
+	evtack_req.event = event;
+	evtack_req.event_context = cpu_to_le32(event_ctx);
+	retval = mpi3mr_admin_request_post(mrioc, &evtack_req,
+	    sizeof(evtack_req), 1);
+	if (retval) {
+		dprint_event_th(mrioc,
+		    "posting event ack request is failed\n");
+		goto out_failed;
+	}
+
+	dprint_event_th(mrioc,
+	    "event ack in the top half for event(0x%02x), event_ctx(0x%08x) is posted\n",
+	    event, event_ctx);
+out:
+	return;
+out_failed:
+	drv_cmd->state = MPI3MR_CMD_NOTUSED;
+	drv_cmd->callback = NULL;
+	clear_bit(cmd_idx, mrioc->evtack_cmds_bitmap);
+}
+
 /**
  * mpi3mr_pcietopochg_evt_th - PCIETopologyChange evt tophalf
  * @mrioc: Adapter instance reference
@@ -3773,6 +3920,7 @@ mpi3mr_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	INIT_LIST_HEAD(&mrioc->fwevt_list);
 	INIT_LIST_HEAD(&mrioc->tgtdev_list);
 	INIT_LIST_HEAD(&mrioc->delayed_rmhs_list);
+	INIT_LIST_HEAD(&mrioc->delayed_evtack_cmds_list);
 
 	mutex_init(&mrioc->reset_mutex);
 	mpi3mr_init_drv_cmd(&mrioc->init_cmds, MPI3MR_HOSTTAG_INITCMDS);
