sleep / wake-up

[Lee Revell]

On Sun, 2006-06-11 at 00:41 +0200, Guennadi Liakhovetski wrote:
> On Sat, 10 Jun 2006, Jon Scully wrote:
> 
> > Also, here's an article (just about 4 days old):
> > http://www.linux.com/article.pl?sid=06/05/24/1716222
> > (I thought the subject sounded familiar ;-)
> 
> Ok, thanks for both replies. That's a good start already! But this is all 
> about __software__ suspend. But aren't some other "hardware" suspend-modes 
> also available on ppc, like suspend-to-RAM? For example, on my system I 
> could say quite a bit of power by stopping the HD, switching off 
> USB-ports, eth, and then putting the CPU to sleep? Would all this be 
> doable by just performing those steps and then clocking the CPU down?
> 

Did you read the article?

"ACPI state S3 -- also know as Suspend-to-RAM -- is the state where
everything in the system enters a low-power state except for RAM, which
consumes a small amount of power in order to retain its contents, so
that upon resuming, everything is loaded back from the memory and all
running applications are restored immediately."

> I must admit, I don't understand the whole idea behind suspending at all. 
> What happens to all applications that went to sleep for 1 second and wake 
> up 2 days later? What about all network connections? timeouts? I have to 
> read some basics...

It's insanely difficult and complicated.  Every single driver and kernel
subsystem has to be changed.  Zillions of man-hours have gone into
getting suspend to work on Linux and it's still not there...

Lee