Re: [linux-pm] [PATCH 3/4] x86 hibernate: Mark ACPI NVS memory region at startup

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Wednesday, 29 of October 2008, Pavel Machek wrote:
> Hi!
> 
> > > > > +static int __init e820_mark_nvs_memory(void)
> > > > > +{
> > > > > +	int i;
> > > > > +
> > > > > +	if (efi_enabled)
> > > > > +		return 0;
> > > > 
> > > > Aha, not unrelated... why is that? EFI does not use acpi? 
> > > 
> > > With EFI we are not supposed to do that.  Rui knows the details.  Rui?
> > > 
> > well, 
> > about EFI nvs memory, I only get
> > "EfiACPIMemoryNVS: The OS and loader must preserve this memory range in
> > the working and ACPI S1???S3 states." in the ACPI spec 3.0b.
> > whether we should save/restore this piece of memory is not clear.

Well. it's clear enough.  Section 15.3.2 evidently refers to E820 and the EFI's
GetMemoryMap() on equal footing.

> > I'd prefer not to touch it currently.
> 
> EFI is a bootloader. Why should we change our runtime behaviour
> depending on bootloader?
> 
> EFI should be still compatible with normal ACPI, right? ...like you
> should be able to boot the same kernel with the same ACPI BIOS using
> EFI or EFI w/ legacy emulation.
> 
> So special-casing it here does not seem right.

I agree.

I'm going to send an updated patch to Len.

Thanks,
Rafael