On 26 October 2015 at 11:51, Michael Turquette <mturquette@xxxxxxxxxxxx> wrote: > 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. Alexander Holler has been looking at that for some time already. Regards, Tomeu > 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 linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- 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
