I don't use hibernate, so I can't be a great help here - but I suspect you'd have better luck looking around at resume hooks.
on 04/08/2012 – Made popular on 04/08/2012
I use e4rat with systemd and it works great. Your not trying to use e4rat and systemd's readahead at the same time are you? I don't use a DM, instead I boot to tty but have autologin and xinit is ran (conditionally) from bashrc. Have you tried this sort of set up to narrow down whether it is actually a DM problem?