Re: [linux-pm] [RFC PATCH 0/4] save and restore ACPI NVS memory during hibernation

[Pavel Machek <pavel@suse.cz>]

Hi!

> According to the ACPI spec, ACPI NVS memory region is required to
> be saved/restored by OS during hibernation.
> 
> Section 15.3.2 ACPI Spec 3.0b,
> "OSPM will call the _PTS control method some time before entering
> a sleeping state, to allow the platform???s AML code to update
> this memory image before entering the sleeping state.
> After the system awakes from an S4 state, OSPM will restore this
> memory area and call the _WAK control method to enable the BIOS
> to reclaim its memory image."
> 
> This patch set add the mechanism to save/restore ACPI NVS memory
> during hibernation.
> 
> Patch 01: call platform_begin before swsusp_shrink_memory.
> 	So that we can allocate enough pages for ACPI NVS memory
> 	before shrink the memory.

Why is it neccessary to allocate memory for a copy? We should be able
to save ACPI NVS area same way we are saving kernel pages, no?
-- 
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