diff --git a/eventlet/api.py b/eventlet/api.py
index 267ec83..82e8f7c 100644
--- a/eventlet/api.py
+++ b/eventlet/api.py
@@ -145,7 +145,7 @@ def trampoline(fd, read=None, write=None, timeout=None):
         hub.remove_descriptor(fileno)
         greenlib.switch(self, fd)
     if timeout is not None:
-        t = hub.schedule_call(timeout, _do_timeout)
+        t = hub.schedule_call(timeout, _do_timeout, fileno)
     hub.add_descriptor(fileno, read and cb, write and cb, _do_close)
     return hub.switch()