As your disk is probably not 'open source' (?), you don't know if there is a really encryption, or if there is a secret password (as for some bios) that permits to access data.
thats exactly what i fear about. it is even possible that there are no encryption at all.
Keep in memory that, whatever you do, if a guy has money and WANTS your data, he can get these.So, as long as you're not a terrorist,
No i am not a terrorist yet ;) So final conclusion - just use software encryption. Thank you.