suspend works, but resume doesn't on Dell desktop

[Mohan Singh]

I have a Dell Dimension 4700, dual booting XP and FreeBSD 5.4. Windows
can hibernate and stand-by fine. I'm trying to do the same (or at
least standby) from FreeBSD.

As I understand it Windows standby == FreeBSD suspend (zzz).

As root, when I run suspend/zzz, it seems to go into standby mode,
just like it does in Windows. But when I resume (by hitting the power
button) it just powers on normally, as if the suspend never happened.

Of course, FreeBSD is not happy about this because the filesystems
were not dismounted properly and starts fsck'ing.

How can I get resume to work properly?

Thanks.