Comment 5 for bug 726053

After some discussion it's been determined that gnome panel just uses a timer every second and updates accordingly, there are other watches involved presumably but the exact code seems difficult to locate.

The suggestion to do this properly is to either wait until there's a fix in the kernel and glib (scheduled some time soon) or to watch for some random dbus traffic that might signify a resume event, or have a 1 second timer that compares the current time with the previously displayed time and triggers an update only if it's changed.