There was a regression in Linux 3.2.65, which unfortunately was included in this weekend's Debian stable point release (7.8) as I didn't point out the bug reports to the stable release team. At least some systems are now failing to resume after suspending to RAM; instead they reboot.

I have tracked down the change that caused this, and it should be fixed as part of a security update soon. The change is in code specific to 64-bit x86 (i.e. the Debian amd64 architecture). If you need suspend/resume to work, you might wish to avoid upgrading the linux-image-3.2.0-4-amd64 package until that future update.

Update: I have uploaded packages with the problematic changes reverted to people.debian.org. The version number is 3.2.65-1+deb7u1~test (lower than the next security update will be). Mail 774436@bugs.debian.org if this doesn't work for you.