Quoting Rafael J. Wysocki (2015-10-25 06:54:39) > On Sun, Oct 25, 2015 at 12:06 AM, Mark Brown <broonie@xxxxxxxxxx> wrote: > > On Sat, Oct 24, 2015 at 04:17:12PM +0200, Rafael J. Wysocki wrote: > > > >> Well, I'm not quite sure why exactly everyone is so focused on probing here. > > > > Probe deferral is really noisy even if it's working fine on a given > > system so it's constantly being highlighted to people in a way that > > other issues aren't if you're not directly having problems. > > > > There's also the understanding people had that the order things get > > bound changes the ordering for some of the other cases (perhaps it's a > > good idea to do that, it seems likely to be sensible?). > > But it really doesn't do that. Also making it do so doesn't help much > in the cases where things can happen asynchronously (system > suspend/resume, runtime PM). > > If, instead, there was a way to specify a functional dependency at the > device registration time, it might be used to change the order of > everything relevant, including probe. That should help to reduce the > noise you're referring to. Taking it a step further, if functional dependencies were understood at link-time then we could optimize link order as well. There are probably lots of optimizations if we only made the effort to understand these dependencies earlier. Constructing the device/resource dependency graph before the device ever boots sounds interesting to me. Regards, Mike > > If the dependency could only be discovered at the probe time, the > order of things might be changed in response to letting the driver > core know about it rather than "just in case", which should be more > efficient. > > Thanks, > Rafael -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
