On Thursday, 12 July 2007 19:09, Huang, Ying wrote: > On Wed, 2007-07-11 at 22:48 -0700, Jeremy Fitzhardinge wrote: > > >> The kexec jump is implemented in the framework of software suspend. In > > >> fact, the kexec based hibernation can be seen as just implementing the > > >> image writing and reading method of software suspend with a kexeced > > >> Linux kernel. > > >> > > > > I guess I'm (still) confused by the terminology here. Do you mean that > > it fits into suspend-to-disk as a disk-writing mechanism, or in > > suspend-to-ram as a way of going to sleep? > > It fits into suspend-to-disk as a disk-writing mechanism. But most > tricks of suspend-to-disk will be no longer necessary in kexec based > hibernation. > > > > I didn't understand the ACPI problem. Does this mean that CONFIG_ACPI must > > > be disabled in the to-be-hibernated kernel, or in the little transient > > > kexec kernel? > > > > > > > I think the point is that if kernel A says "I'm suspending" and calls > > the suspend method on all its devices, then kernel B finds that it has > > no powered on devices to work with. But then couldn't it turn on the > > ones it wants anyway? And don't you want to suspend them, to make sure > > they're not still DMAing memory while B is trying to shuffle everything > > off to disk? > > The devices should be put quiescent state to stop DMA like things. But > they do not need to be put in low power state. Exactly. Morover, I don't think it would be correct to put them into low power states. Greetings, Rafael -- "Premature optimization is the root of all evil." - Donald Knuth _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
