diff --git a/arch/arm/src/lpc17xx/lpc17_usbhost.c b/arch/arm/src/lpc17xx/lpc17_usbhost.c
index b314e7029e..f195c0ed75 100644
--- a/arch/arm/src/lpc17xx/lpc17_usbhost.c
+++ b/arch/arm/src/lpc17xx/lpc17_usbhost.c
@@ -3220,15 +3220,15 @@ static int lpc17_cancel(FAR struct usbhost_driver_s *drvr, usbhost_ep_t ep)
   irqstate_t flags;
   int ret = OK;
 
+  DEBUGASSERT(ed != NULL);
+
   /* These first steps must be atomic as possible */
 
-  flags  = irqsave();
+  flags = irqsave();
 
-  /* It might be possible for no transfer to be in progress */
+  /* It is possible there there is no transfer to be in progress */
 
-  DEBUGASSERT(ed != NULL && ed->xfrinfo != NULL);
   xfrinfo = ed->xfrinfo;
-
   if (xfrinfo)
     {
       /* It would be an usage error to use the interface to try to cancel a
diff --git a/drivers/usbdev/cdcacm.c b/drivers/usbdev/cdcacm.c
index 6e0b331f40..6e726816b9 100644
--- a/drivers/usbdev/cdcacm.c
+++ b/drivers/usbdev/cdcacm.c
@@ -1467,7 +1467,7 @@ static int cdcacm_setup(FAR struct usbdevclass_driver_s *driver,
               {
                 /* Save the new line coding in the private data structure.  NOTE:
                  * that this is conditional now because not all device controller
-                 * drivers supported provisioni of EP0 OUT data with the setup
+                 * drivers supported provision of EP0 OUT data with the setup
                  * command.
                  */
 
@@ -1476,6 +1476,8 @@ static int cdcacm_setup(FAR struct usbdevclass_driver_s *driver,
                     memcpy(&priv->linecoding, dataout, SIZEOF_CDC_LINECODING);
                   }
 
+                /* Respond with a zero length packet */
+
                 ret = 0;
 
                 /* If there is a registered callback to receive line status info, then
@@ -1504,7 +1506,7 @@ static int cdcacm_setup(FAR struct usbdevclass_driver_s *driver,
                 index == CDCACM_NOTIFID)
               {
                 /* Save the control line state in the private data structure. Only bits
-                 * 0 and 1 have meaning.
+                 * 0 and 1 have meaning.  Respond with a zero length packet.
                  */
 
                 priv->ctrlline = value & 3;
@@ -1534,7 +1536,7 @@ static int cdcacm_setup(FAR struct usbdevclass_driver_s *driver,
                 index == CDCACM_NOTIFID)
               {
                 /* If there is a registered callback to handle the SendBreak request,
-                 * then callout now.
+                 * then callout now.  Respond with a zero length packet.
                  */
 
                 ret = 0;
@@ -1589,6 +1591,8 @@ static int cdcacm_setup(FAR struct usbdevclass_driver_s *driver,
         }
     }
 
+  /* Returning a negative value will cause a STALL */
+
   return ret;
 }
 
diff --git a/drivers/usbhost/usbhost_cdcacm.c b/drivers/usbhost/usbhost_cdcacm.c
index 1e9691fbbf..4f832ac31c 100644
--- a/drivers/usbhost/usbhost_cdcacm.c
+++ b/drivers/usbhost/usbhost_cdcacm.c
@@ -650,7 +650,7 @@ static int usbhost_linecoding_send(FAR struct usbhost_cdcacm_s *priv)
   ctrlreq->req     = ACM_SET_LINE_CODING;
 
   usbhost_putle16(ctrlreq->value, 0);
-  usbhost_putle16(ctrlreq->index, priv->dataif);
+  usbhost_putle16(ctrlreq->index, priv->ctrlif);
   usbhost_putle16(ctrlreq->len,   SIZEOF_CDC_LINECODING);
 
   /* And send the request */
@@ -723,7 +723,7 @@ static void usbhost_notification_work(FAR void *arg)
                                        USB_REQ_RECIPIENT_INTERFACE)) &&
               (inmsg->notification == ACM_SERIAL_STATE) &&
               (value               == 0) &&
-              (index               == priv->dataif) &&
+              (index               == priv->ctrlif) &&
               (len                 == 2))
             {
               uint16_t state = usbhost_getle16(inmsg->data);
@@ -2062,9 +2062,16 @@ errout:
 static int usbhost_disconnected(struct usbhost_class_s *usbclass)
 {
   FAR struct usbhost_cdcacm_s *priv = (FAR struct usbhost_cdcacm_s *)usbclass;
+#ifndef CONFIG_USBHOST_CDCACM_BULKONLY
+  FAR struct usbhost_hubport_s *hport;
+#endif
   irqstate_t flags;
 
   DEBUGASSERT(priv != NULL);
+#ifndef CONFIG_USBHOST_CDCACM_BULKONLY
+  DEBUGASSERT(priv->usbclass.hport != NULL);
+  hport = priv->usbclass.hport;
+#endif
 
   /* Set an indication to any users of the CDC/ACM device that the device
    * is no longer available.
@@ -2073,6 +2080,19 @@ static int usbhost_disconnected(struct usbhost_class_s *usbclass)
   flags              = irqsave();
   priv->disconnected = true;
 
+#ifndef CONFIG_USBHOST_CDCACM_BULKONLY
+  /* Cancel any pending asynchronous I/O */
+
+  if (priv->intin)
+    {
+      int ret = DRVR_CANCEL(hport->drvr, priv->intin);
+      if (ret < 0)
+        {
+         udbg("WARNING: DRVR_CANCEL failed: %d\n", ret);
+        }
+    }
+#endif
+
   /* Now check the number of references on the class instance.  If it is one,
    * then we can free the class instance now.  Otherwise, we will have to
    * wait until the holders of the references free them by closing the