Re: [PATCH 0/2] Introduce CONFIG_HIBERNATION and CONFIG_SUSPEND (updated)

[Len Brown <lenb@kernel.org>]

On Sunday 29 July 2007 20:21, Linus Torvalds wrote:
> 
> Ok, I took this, and modified Len's patch to re-introduce ACPI_SLEEP on 
> top of it (I took the easy way out, and just made PM_SLEEP imply 
> ACPI_SLEEP, which should make everything come out right. I could have 
> dropped ACPI_SLEEP entirely in favour of PM_SLEEP, but that would have 
> implied changing more of Len's patch than I was really comfy with).
> 
> Len, Rafael, please do check that the end result looks ok. 

SUSPEND depends only on (!SMP || SUSPEND_SMP_POSSIBLE).
This means that while we limit the architectures it can build on
if they are SMP, it can build on any !SMP architecture --
which probably isn't what we want.

I think the right way to go is your SUSPEND_UP_POSSIBLE suggestion.
Honestly, I though it was overly verbose when I first read it,
but I like it better now, especially since it works;-)
I'll reply w/ an incremental patch.

> I suspect ACPI could now take the PM_SLEEP/SUSPEND/HIBERNATE details into 
> account, and that some of the code is not necessary when HIBERNATE is not 
> selected, for example, but I'm not at all sure that it's worth it being 
> very fine-grained.

As you know, I don't think that it is worth dedicated config options
to save 16KB on an SMP+ACPI kernel.  The prospect of adding code to
slice that 16KB into finer grain savings seems even less worthwhile.

-Len