Re: suspend2 merge (was Re: [Suspend2-devel] Re: CFS and suspend2: hang in atomic copy)

Linus Torvalds
2007-04-25T22:59:01Z

On Thu, 26 Apr 2007, Pavel Machek wrote:
>
> Suspend syncs caches/spins down. Freeze does not do anything.
>
> That's okay, I keep claiming "freeze" is subset of "suspend". Can you
> name device where that is not true?

Sure. Like just about any PCI device that doesn't do things on its own.

A "freeze" does nothing at all, or perhaps shuts down the reader side
(for something like a network controller).

A "suspend" does "write D3 to the suspend register". Absolutely zero in
common.

> Remember we do
>
> suspend(PMSG_FREEZE)
> atomic snapshot
> resume()
> write snapshot.

AND THAT IS STUPID. It mixes up "suspend()" and creating a snapshot in
ways that are totally idiotic. There is nothing in common!

Linus