serialcon: Some fixes for fast data transfer

Our glib integration had a defect that could cause stalls when streaming
a lot of data (like doing a cat /var/log/messages)

Also, add some tweaks to make the previously stated situation perform
better anyways.

src/virtManager/libvirtglib.py

@@ -179,6 +179,8 @@ def glib_event_timeout_dispatch(opaque):
     data = opaque
     data.cb(data.timer, data.opaque)
 
+    return True
+
 def glib_event_timeout_add(interval, cb, opaque):
     data = EventTimer()
 

src/virtManager/serialcon.py

@@ -145,7 +145,7 @@ class LibvirtConsoleConnection(ConsoleConnection):
 
         if events & libvirt.VIR_EVENT_HANDLE_READABLE:
             try:
-                got = self.stream.recv(1024)
+                got = self.stream.recv(1024 * 100)
             except:
                 logging.exception("Error receiving stream data")
                 self.close()
@@ -154,8 +154,9 @@ class LibvirtConsoleConnection(ConsoleConnection):
             if got == -2:
                 return
 
+            queued_text = bool(self.streamToTerminal)
             self.streamToTerminal += got
-            if self.streamToTerminal:
+            if not queued_text:
                 self.safe_idle_add(self.display_data, terminal)
 
         if (events & libvirt.VIR_EVENT_HANDLE_WRITABLE and