[OLPC-devel] Re: ACPI: Idle Processor PM Improvements

[Jordan Crouse]

On 01/09/06 05:12 +0100, Matthew Garrett wrote:
> On Thu, Aug 31, 2006 at 11:53:04PM -0400, Len Brown wrote:
> 
> > The Geode doesn't suport any C-states -- so ACPI wouldn't help them there anyway.
> 
> Are you sure of that? The docs I have here suggest C1 and C2, but it's 
> possible that that's just the companion chip and they aren't implemented 
> in the CPU.

C1 is essentially suspend on hlt.  We have something called Automatic Hardware
Clock Gating that kicks in when the blocks go unused, so that saves a bit
more power (especially in the south bridge) then we would with just a simple
hlt.  In any event, this already happens without the assistance of ACPI.

The 5536 has support for a C2 state as well, but I don't know if that
has any effect on the GX or not.

Jordan

-- 
Jordan Crouse
Senior Linux Engineer
Advanced Micro Devices, Inc.
<www.amd.com/embeddedprocessors>