Hi! > > Except that FREEZE is also neccessary for kexec, would be needed even > > with selective resume, and is probably good idea for powerdown/reboot > > too? > > I don't have any problem with ways to quiesce the whole > system ... but it's not exactly a PM operation either. Well, its very similar to most PM operations and I do not think duplicating infrastructure would be good idea. > > [Oh and btw stop whining about selective resume -- it is not going to > > happen anytime soon. It is probably not going to happen, period. It is > > bad idea and I do not want it near my code.] > > Such unsupported/unsupportable assertions don't help. Ignoring previous discussion is not exactly helpfull, either. > There's nothing in the hardware that prevents systems > from keeping most components in low power mode while > others are still active. And likewise there's no > reason for software to prevent it either. Agreed. And there's no reason to do it during system suspend, either. > In fact I'm totally at a loss to understand why you > have such a strong objection to the idea. There > are any number of embedded systems that rely on > selective suspend and resume -- along with other > power management techniques! -- to minimize power > drain. Why should Linux cripple itself by ruling > out such techniques? Penguins with just one flipper > havea hard time swimming ... :) Do selective suspend during runtime power managment, that's okay. But its useless for suspend-to-disk. (And I do not see how you could use it for suspend-to-ram, I hope you do not want that). Lets see, so you suggest to * SUSPEND all but swap device and parents * Snapshot * Write image to disk * SUSPEND swap device and parents * Powerdown Oh no, that does not work, if swap device or its parents uses DMA, you've corrupted data. You'd have to do * SUSPEND all but swap device and parents * FREEZE swap device and parents * Snapshot * UNFREEZE swap device and parents * Write * SUSPEND swap device and parents Which means that you still need that FREEZE state, and you get more complicated code. (And I have not yet introduce details like system devices). Pavel -- People were complaining that M$ turns users into beta-testers... ...jr ghea gurz vagb qrirybcref, naq gurl frrz gb yvxr vg gung jnl!
