ehci: keep the frame timer running in case the guest asked for frame list rollover interrupts

Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/usb/hcd-ehci.c

@@ -964,6 +964,9 @@ static void ehci_opreg_write(void *ptr, hwaddr addr,
 
     case USBINTR:
         val &= USBINTR_MASK;
+        if (ehci_enabled(s) && (USBSTS_FLR & val)) {
+            qemu_bh_schedule(s->async_bh);
+        }
         break;
 
     case FRINDEX:
@@ -2220,6 +2223,10 @@ static void ehci_frame_timer(void *opaque)
         ehci->async_stepdown = 0;
     }
 
+    if (ehci_enabled(ehci) && (ehci->usbintr & USBSTS_FLR)) {
+        need_timer++;
+    }
+
     if (need_timer) {
         /* If we've raised int, we speed up the timer, so that we quickly
          * notice any new packets queued up in response */