On Monday 02 April 2007 1:04 pm, Alan Stern wrote: > On Mon, 2 Apr 2007, David Brownell wrote:
> > This is the kind of thing that the pm_parent relationship was (AFAICT) > > originally supposed to handle. Of course, it doesn't/can't, given the > > current implementation ... that relationship is never used. > > Just so. In fact, there almost certainly are other dependencies that > nobody is aware of, simply because they have never had a chance to bite. In any given system, yes there are bugs lurking. But I was more concerned with a provably wrong assumption made by the current framework. Such things cause cascading fragility. As Thomas mentioned, HPET isn't the only place where a "linear" model fails. > Such things can be rather difficult to pin down when they occur. I would > be happy enough to leave matters as they are, with a strict LIFO approach. I wouldn't. Much better to have a solid handle on the interdependencies than to need to cope, long term, with a framework that doesn't allow that. Remember also that a LIFO model assumes that there's only one sequence by which the hardware powers up/down ... i.e. that there's no runtime PM going on, whereby large chunks are regularly powered down/up based on usage. Better runtime PM becomes more important as system complexity rises. - Dave - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
