Comment 3 for bug 45661

I can suspend to disk fine through
/usr/share/hal/scripts/hal-system-power-hibernate, but not through kpowersave. Screen goes off, but the computer does not halt. I have to forcefully turn it off and then resuming does not work.

From looking at kpowersave.cpp, it does this:
"""
        // sent to admin interface if we are run as root
        if (getuid() == 0)
                res = dbusSendSimpleMessage(ADMIN_MESSAGE,
                                            "SuspendToDisk");
        else
                res = dbusSendSimpleMessage(ACTION_MESSAGE,
                                            "SuspendToDisk");
"""

And this seems to arrive in /usr/lib/powersave/do_acpi_sleep here:
   suspend2disk)
        IMG_SZ=0
        read IMG_SZ < /sys/power/image_size
        $MYECHO /sys/power/state disk
        RET=$? # 28=ENOSPC, "not enough swap."
        #
        # the logic here is:
        # if image_size > 0 (without kernel support, IMG_SZ will be zero),
        # and we got ENOSPC, then try again with image_size set to zero.
        if [ $RET -eq 28 -a $IMG_SZ -ne 0 ]; then # try again with minimal image size
                echo 0 > /sys/power/image_size
                $MYECHO /sys/power/state disk
                RET=$?
                echo $IMG_SZ > /sys/power/image_size
        fi
        [ "$SUSPEND2DISK_RESTORE_CLOCK" == "yes" ] && $HWCLOCK $OPT
        ;;

I've found a patch for kpowersave which seems to use HAL (and therefor acpi-support) instead:
http://www.mail-archive.com/powersave-devel%40forge.novell.com/msg00687.html
This might be available in a new upstream release.