On Fri, Mar 09, 2007 at 01:32:53PM -0800, Chuck Swiger wrote:
> On Mar 9, 2007, at 11:20 AM, Bucky Katz wrote:
> >>An ACPI-aware BIOS may have support for loading the state of RAM
> >>directly from disk, although the preferred method involves the OS
> >>being ACPI-aware and handling the load of RAM from disk itself using
> >>the OS-specific device drivers.  The former approach probably
> >>requires a dedicated partition which the BIOS uses, whereas the
> >>approach using the OS-specific drivers can read and write the state
> >>of memory to a file using whatever native filesystem(s) the OS
> >>itself supports.
> >
> >ACPI is great for PCs, but sucks for embedded systems, which rarely,
> >if ever, have hardware support for ACPI. It would be nice if a
> >framework were able to cope with not relying on ACPI.
> 
> You have a good point, but if the firmware/BIOS doesn't support ACPI  
> at least to some extent, how is one going to get the system into a S4  
> state?  :-)

You don't need harware support at all: just save the state to disk and
poweroff. When the kernel loads on next power up, restore the state.
I think it's this way that solaris does suspend to disk on sparc
hardware.

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
     NetBSD: 26 ans d'experience feront toujours la difference
--