1 files changed, 11 insertions, 1 deletions

diff --git a/hw/usb/dev-hub.c b/hw/usb/dev-hub.c
index 504c98c350..0b71abd028 100644
--- a/hw/usb/dev-hub.c
+++ b/hw/usb/dev-hub.c
@@ -25,6 +25,7 @@
 #include "trace.h"
 #include "hw/usb.h"
 #include "hw/usb/desc.h"
+#include "qemu/error-report.h"
 
 #define NUM_PORTS 8
 
@@ -32,6 +33,7 @@ typedef struct USBHubPort {
     USBPort port;
     uint16_t wPortStatus;
     uint16_t wPortChange;
+    uint16_t wPortChange_reported;
 } USBHubPort;
 
 typedef struct USBHubState {
@@ -466,8 +468,11 @@ static void usb_hub_handle_data(USBDevice *dev, USBPacket *p)
             status = 0;
             for(i = 0; i < NUM_PORTS; i++) {
                 port = &s->ports[i];
-                if (port->wPortChange)
+                if (port->wPortChange &&
+                    port->wPortChange_reported != port->wPortChange) {
                     status |= (1 << (i + 1));
+                }
+                port->wPortChange_reported = port->wPortChange;
             }
             if (status != 0) {
                 for(i = 0; i < n; i++) {
@@ -514,6 +519,11 @@ static int usb_hub_initfn(USBDevice *dev)
     USBHubPort *port;
     int i;
 
+    if (dev->port->hubcount == 5) {
+        error_report("usb hub chain too deep");
+        return -1;
+    }
+
     usb_desc_create_serial(dev);
     usb_desc_init(dev);
     s->intr = usb_ep_get(dev, USB_TOKEN_IN, 1);