[OLPC-devel] Thoughts on S3 resume.

[Ronald G Minnich]

Matthew Garrett wrote:
> On Thu, Jul 27, 2006 at 08:29:08AM -0600, Ronald G Minnich wrote:
> 
> 
>>do you mean protected mode or paging enabled? Linuxbios goes into 
>>protected in the first 10 instructions or so. If it is an s3 restart, 
>>then linuxbios can pop out to real mode and call the kernel if needed.
> 
> 
> Right now, the Linux ACPI wakeup code expects to come back up in 16-bit 
> mode with segmented memory - arch/i386/kernel/acpi/wakeup.S is what ends 
> up getting run. The wakeup code gets copied into low memory on startup, 
> and the address copied into the wakeup register. ACPI BIOSes then just 
> jump to that address on startup. If Linuxbios is doing some of this 
> setup already, I guess we can just work from there.
> 

it's not done, but it's easy, all that linuxbios needs to be able to do 
is figure out that it has to turn on memory, then jump to a special place.

This is looking easier and easier ...

ron