2 files changed, 8 insertions, 1 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 4d0f1e5afeb..ca425d5b5ea 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,10 @@
+2012-06-30  Eli Zaretskii  <eliz@gnu.org>
+
+        * emacs-lisp/timer.el (timer-until): Subtract results of
+        float-time, instead of taking float-time of the result of
+        time-subtract, since float-time signals an error for negative time
+        arguments.
+
 2012-06-30  Chong Yidong  <cyd@gnu.org>
 
         * xml.el (xml-*-re): Convert defvars into defconsts, and
diff --git a/lisp/emacs-lisp/timer.el b/lisp/emacs-lisp/timer.el
index eab96fe202a..a66d5972d82 100644
--- a/lisp/emacs-lisp/timer.el
+++ b/lisp/emacs-lisp/timer.el
@@ -268,7 +268,7 @@ how many will really happen."
   "Calculate number of seconds from when TIMER will run, until TIME.
 TIMER is a timer, and stands for the time when its next repeat is scheduled.
 TIME is a time-list."
-  (float-time (time-subtract time (timer--time timer))))
+  (- (float-time time) (float-time (timer--time timer))))
 
 (defun timer-event-handler (timer)
   "Call the handler for the timer TIMER.