On 21 December 2017 at 02:39, Rafael J. Wysocki <rafael@xxxxxxxxxx> wrote: > On Wed, Dec 20, 2017 at 3:09 PM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: >> The runtime PM deployment in the phy core is deployed using the phy core >> device, which is created by the phy core and assigned as a child device of >> the phy provider device. >> >> The behaviour around the runtime PM deployment cause some issues during >> system suspend, in cases when the phy provider device is put into a low >> power state via a call to the pm_runtime_force_suspend() helper, as is the >> case for a Renesas SoC, which has its phy provider device attached to the >> generic PM domain. >> >> In more detail, the problem in this case is that pm_runtime_force_suspend() >> expects the child device of the provider device, which is the phy core >> device, to be runtime suspended, else a WARN splat will be printed >> (correctly) when runtime PM gets re-enabled at system resume. > > So we are now trying to work around issues with > pm_runtime_force_suspend(). Lovely. :-/ Yes, we have to, as pm_runtime_force_suspend() is widely deployed. Or are you saying we should just ignore all issues related to it? Of course, if we had something that could replace pm_runtime_force_suspend(), that would be great, but there isn't. > >> In the current scenario, even if a call to phy_power_off() triggers it to >> invoke pm_runtime_put() during system suspend, the phy core device doesn't >> get runtime suspended, because this is prevented in the system suspend >> phases by the PM core. >> >> To solve this problem, let's move the runtime PM deployment from the phy >> core device to the phy provider device, as this provides the similar >> behaviour. Changing this makes it redundant to enable runtime PM for the >> phy core device, so let's avoid doing that. > > I'm not really convinced that this approach is the best one to be honest. > > I'll have a deeper look at this in the next few days, stay tuned. There is different ways to solve this, for sure. I picked this one, because I think it's the most trivial thing to do, and it shouldn't cause any other problems. I think any other option would involve assigning ->suspend|resume() callbacks to the phy core device, but that's fine too, if you prefer that. Also, I have considered how to deal with wakeup paths for phys, although I didn't want to post changes as a part of this series, but maybe I should to give a more complete picture? Kind regards Uffe
