What does "stopping userspace" mean? You already said it does not mean
disabling interrupts. But using the freezer is also not an option,
since the avoidance of that is the main reason for the kexec approach in
the first place.
[snip]
It should be possible on any system to do a hibernate followed by a
shutdown (and then resume properly, without any problems). Thus, for
handling suspend to both, you resume as if the system had been shutdown,
rather than resuming as if the system came from S4.
--
Jeremy Maitin-Shepard
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