This puts the word «end» to my various tries to have suspend to ram working on Enterprise.
Last night I tried the openSUSE wiki page that Slobodan D. Sredojevic linked on his documentation, and while trying to suspend the system in single user mode, without X running or anything, I finally found what causes the freeze after a few seconds from resume: a machine check exception (MCE).
The output is quite clear from the kernel already, the problem is in hardware; mcelog (which is quite useless considering the MCEs don’t get logged after resumes, so if you didn’t copy the output manually you’re screwed) reports it as
CPU 0 0 data cache STATUS 0 MCGSTATUS 0, that seems to point to a data cache corruption in the CPU… duh!
I also tried updating the BIOS, just to make sure, but there is no change (and it scared me because it change the Promise controller setup from standard to RAID, and it wasn’t of course able to find any RAID array defined). Seems like my hardware don’t support suspend to ram, for some reason.
Update: I also now tried checking (and fixing) my ACPI DSDT, but that didn’t help. I’m not sure if I should submit my fixes to ASUS, and ask them if they have any clue, but this motherboard (A8V Deluxe) is three years old now, and I’m not sure if they care at all about it anymore.