Re: Hibernation considerations

[david@lang.hm]

On Mon, 16 Jul 2007, Al Boldi wrote:

> david@lang.hm wrote:
> > suspend-to-RAM should not involve kexec, the only reason for doing the
> > kexec to to get a seperate userspace to use for suspend-to-disk operations
> > instead of trying to partially freeze the sustem and keep useing it.
> Or you could do suspend-to-disk-and-RAM.  But in the above case, it was meant
> to test kexec compatibility with device suspend/resume calls.
the point I am trying to make here is that there is no reason that the 
kexec approach needs to do _any_ suspend/resume calls.
all that is needed is the ability of the new kernel to initialize the 
devices it needs.
suspend-to-disk-and-ram could be implemented as three 
seperate steps
1. suspend-to-disk

2. resume-from-disk

3. suspend-to-ram

followed by either

4. resume-from-ram

or

4. battery dies and loptop powers off completely

5. power-on boot.

6. resume-from-disk

all that you need to do is to make sure that the system doesn't run 
anything that would affect permanent media or the outside world between 
steps #2 and #3
yes it's more steps, but each step is logicly seperate, and each step will 
be excercised on a regular basis, so the combination of the steps will 
also be reliable.
this is far better then creating yet another way to pause the system that 
only a few people will use.
David Lang
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