* lisp/battery.el (display-battery-mode): If `battery-status-function'

or `battery-mode-line-format' is nil, display the message and set
`display-battery-mode' to nil.

Fixes: debbugs:9363

2 files changed, 16 insertions, 7 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 064e745d1f5..6ce18817f4f 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2011-08-25  Juri Linkov  <juri@jurta.org>
+
+        * battery.el (display-battery-mode): If `battery-status-function'
+        or `battery-mode-line-format' is nil, display the message and set
+        `display-battery-mode' to nil (bug#9363).
+
 2011-08-25  Eli Zaretskii  <eliz@gnu.org>
 
         * buff-menu.el (Buffer-menu-buffer+size): Remove calls to
diff --git a/lisp/battery.el b/lisp/battery.el
index e0bba96b655..f5c01fbef58 100644
--- a/lisp/battery.el
+++ b/lisp/battery.el
@@ -173,13 +173,16 @@ seconds."
   (setq battery-mode-line-string "")
   (or global-mode-string (setq global-mode-string '("")))
   (and battery-update-timer (cancel-timer battery-update-timer))
-  (if (not display-battery-mode)
-      (setq global-mode-string
-            (delq 'battery-mode-line-string global-mode-string))
-    (add-to-list 'global-mode-string 'battery-mode-line-string t)
-    (setq battery-update-timer (run-at-time nil battery-update-interval
-                                            'battery-update-handler))
-    (battery-update)))
+  (if (and battery-status-function battery-mode-line-format)
+      (if (not display-battery-mode)
+          (setq global-mode-string
+                (delq 'battery-mode-line-string global-mode-string))
+        (add-to-list 'global-mode-string 'battery-mode-line-string t)
+        (setq battery-update-timer (run-at-time nil battery-update-interval
+                                                'battery-update-handler))
+        (battery-update))
+    (message "Battery status not available")
+    (setq display-battery-mode nil)))
 
 (defun battery-update-handler ()
   (battery-update)