On Fri 2008-07-11 21:18:34, Rafael J. Wysocki wrote: > On Friday, 11 of July 2008, Pavel Machek wrote: > > On Wed 2008-07-09 21:37:18, Rafael J. Wysocki wrote: > > > On Tuesday, 8 of July 2008, Pavel Machek wrote: > > > > 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? > > > > > > Because we want to restore it from the hibernated kernel (when it gets control > > > back again). > > > > Why is that important? So we can run some ACPI methods from hibernated > > kernel before restoring it? > > We're supposed to restore it right prior to executing _WAK, which is after > we've executed _BFS. This is a bit theoretical, because no one seems to > actaully implement _BFS, but well. Could we just call _BFS from the "loading" kernel, instead? That would save us that copying code... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
