Mark Brown <broonie@xxxxxxxxxx> writes: > On Fri, Oct 24, 2014 at 09:12:39AM -0700, Kevin Hilman wrote: >> Ulf Hansson <ulf.hansson@xxxxxxxxxx> writes: > >> > There may be more than one device in a PM domain which then will be >> > probed at different points in time. > >> > Depending on timing and runtime PM support, in for the device related >> > driver/subsystem, a PM domain may be advised to power off after a >> > successful probe sequence. > >> > A general requirement for a device within a PM domain, is that the >> > PM domain must stay powered during the probe sequence. To cope with >> > such requirement, let's add two new APIs, dev_pm_domain_get|put(). > >> I'm confused. Why arent' pm_runtime_get*() and pm_runtime_put*() working? > >> What's not explained here (or what I'm not understanding) is why a PM >> domain is powering off if it has active devices. > > The issue AIUI is what happens during system boot - if one device in a > domain probes and marks itself runtime idle then that will trigger > domain powerdown even if there is another device in the domain that > hasn't yet been probed. This can cause undesirable glitches (or worse) > during boot depending on what's getting powered down. I'm not quite seeing how this series fixes that problem. Looking at platform devices in PATCH 4/9, the new _get() and _put() are still happening around ->probe(), so if a platform device runtime suspends after probe, don't we still have a PM domain that can turn off? Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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