Messages in this thread | | | Date | Tue, 10 Aug 2004 12:13:08 +0200 | From | Pavel Machek <> | Subject | Re: [RFC] Fix Device Power Management States |
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Hi!
> > Well, "no DMA" needs to be part of definition, too, because some > > devices (USB) do DMA only if they have nothing to do. > > I don't understand; that doesn't sound healthy.
It is not healthy. It is basicaly misdesigned piece of hardware called UHCI. It simply does DMA all the time :-(.
> > if something like this gets merged, it will immediately break swsusp > > because initially no drivers will have "stop" methods. > > > > Passing system state down to drivers and having special "quiesce" > > (as discussed in rather long thread) state has advantage of > > automagicaly working on drivers that ignore u32 parameter of suspend > > callback (and that's most of them). David's patches do not bring us > > runtime suspend capabilities, but do not force us to go through all > > the drivers, either... > > Nothing is free. ;) > > We've been talking about creating and merging a sane power management > model for 3+ years now. It's always been known that the drivers will have > to be modified to support a sane model. It's a fact of life. At some > point, we have to bite the bullet and do the work. I see that time rapidly > approaching. > > I do not intend to merge a patch that will break swsusp in a stable > kernel. However, we do have this wonderful thing called the -mm tree in > which we can a) evolve the model, b) get large testing coverage and c) > solicit driver fixes. > > Once the swsusp consolidation is merged upstream, I will merge a new > device power model in -mm, and we can start working on the drivers. How > does that sound?
It sounds like an acceptable plan. I see no real disadvantage in "suspend with parameter X means quiesce", and I think we'd get smaller patch that way, but if you go through -mm like this, we can do it.
Pavel -- Horseback riding is like software... ...vgf orggre jura vgf serr. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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