Comment 34 for bug 134238

The following is the case on my IBM ThinkPad X32 running Intrepid Ibex on September 10th:

I couldn't suspend with pm-suspend but it worked with pm-suspend-hybrid and pm-hibernate. Also, the suspend option had gone missing from my Gnome Power Manager menu.
pm-is-supported --suspend failed while --hibernate and --suspend-hybrid succeeded.
After some investigation I found that the reason was that /usr/lib/pm-utils/pm-functions chose to try and use uswsusp methods in general (s2disk, s2both, s2ram) for the various suspend functions because of the presence of s2disk:
"
    # Try userspace software suspend
    if [ -c /dev/snapshot ] && command_exists s2disk ; then
        SLEEP_MODULE="uswsusp"
    fi
"
Now s2ram doesn't come with uswsusp any longer, so later on the command will not succeed and the check needs to be altered.

Removing uswsusp fixed this problem for me, because /usr/lib/pm-utils/pm-functions chose the default "kernel" method for suspend instead now that s2disk didn't exist any longer, and now it works fine for me.
Gnome Power Manager still doesn't show the suspend command in its menu, but that might show up after a reboot.
uname -a yields "Linux skx 2.6.27-2-generic #1 SMP Thu Aug 28 17:20:02 UTC 2008 i686 GNU/Linux" for what it's worth.