Fix/uorb listener fetch only sensors

system/uorb/Kconfig

@@ -16,10 +16,15 @@ config UORB_PRIORITY
 
 config UORB_STACKSIZE
 	int "stack size"
+	default 4096 if UORB_FORMAT
 	default DEFAULT_TASK_STACKSIZE
+	---help---
+		UORB_FORMAT needs around 2.2KB of stack for the listener, which
+		does not fit in a DEFAULT_TASK_STACKSIZE of 2048.
 
 config UORB_FORMAT
 	bool
+	select LIBC_PRINT_EXTENSION
 	default n
 
 config UORB_LISTENER

system/uorb/listener.c

@@ -200,15 +200,31 @@ static int listener_create_dir(FAR char *dir, size_t size)
 static int listener_subscribe(FAR struct listen_object_s *tmp,
                               bool nonwakeup)
 {
+  int flags;
+  int fd;
+
   if (nonwakeup)
     {
-      return orb_subscribe_multi_nonwakeup(tmp->object.meta,
-                                           tmp->object.instance);
+      fd = orb_subscribe_multi_nonwakeup(tmp->object.meta,
+                                         tmp->object.instance);
     }
   else
     {
-      return orb_subscribe_multi(tmp->object.meta, tmp->object.instance);
+      fd = orb_subscribe_multi(tmp->object.meta, tmp->object.instance);
+    }
+
+  if (fd < 0)
+    {
+      return fd;
+    }
+
+  flags = fcntl(fd, F_GETFL, 0);
+  if (flags >= 0)
+    {
+      fcntl(fd, F_SETFL, flags | O_NONBLOCK);
     }
+
+  return fd;
 }
 
 /****************************************************************************
@@ -897,6 +913,8 @@ static void listener_monitor(FAR struct listen_list_s *objlist,
 
   while ((!nb_msgs || nb_recv_msgs < nb_msgs) && !g_should_exit)
     {
+      orb_abstime start = orb_absolute_time();
+
       if (poll(&fds[0], nb_objects, timeout * 1000) > 0)
         {
           i = 0;
@@ -939,6 +957,16 @@ static void listener_monitor(FAR struct listen_list_s *objlist,
                        "Giving up. err:%d", timeout, errno);
           break;
         }
+
+      if (interval != 0)
+        {
+          orb_abstime elapsed = orb_absolute_time() - start;
+
+          if (elapsed < (orb_abstime)interval)
+            {
+              usleep((unsigned)((orb_abstime)interval - elapsed));
+            }
+        }
     }
 
   i = 0;