On Tue, 8 Oct 2024 at 20:25, Rafael J. Wysocki <rafael@xxxxxxxxxx> wrote: > > On Tue, Oct 8, 2024 at 12:35 AM Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > > > > On Tue, 8 Oct 2024 at 00:25, Laurent Pinchart > > <laurent.pinchart@xxxxxxxxxxxxxxxx> wrote: > > > > > > Hi Ulf, > > > > > > On Tue, Oct 08, 2024 at 12:08:24AM +0200, Ulf Hansson wrote: > > > > On Mon, 7 Oct 2024 at 20:49, Laurent Pinchart wrote: > > > > > On Fri, Oct 04, 2024 at 04:38:36PM +0200, Ulf Hansson wrote: > > > > > > On Fri, 4 Oct 2024 at 11:41, Sakari Ailus wrote: > > > > > > > > > > > > > > Hello everyone, > > > > > > > > > > > > > > This set will switch the users of pm_runtime_put_autosuspend() to > > > > > > > __pm_runtime_put_autosuspend() while the former will soon be re-purposed > > > > > > > to include a call to pm_runtime_mark_last_busy(). The two are almost > > > > > > > always used together, apart from bugs which are likely common. Going > > > > > > > forward, most new users should be using pm_runtime_put_autosuspend(). > > > > > > > > > > > > > > Once this conversion is done and pm_runtime_put_autosuspend() re-purposed, > > > > > > > I'll post another set to merge the calls to __pm_runtime_put_autosuspend() > > > > > > > and pm_runtime_mark_last_busy(). > > > > > > > > > > > > That sounds like it could cause a lot of churns. > > > > > > > > > > > > Why not add a new helper function that does the > > > > > > pm_runtime_put_autosuspend() and the pm_runtime_mark_last_busy() > > > > > > things? Then we can start moving users over to this new interface, > > > > > > rather than having this intermediate step? > > > > > > > > > > I think the API would be nicer if we used the shortest and simplest > > > > > function names for the most common use cases. Following > > > > > pm_runtime_put_autosuspend() with pm_runtime_mark_last_busy() is that > > > > > most common use case. That's why I like Sakari's approach of repurposing > > > > > pm_runtime_put_autosuspend(), and introducing > > > > > __pm_runtime_put_autosuspend() for the odd cases where > > > > > pm_runtime_mark_last_busy() shouldn't be called. > > > > > > > > Okay, so the reason for this approach is because we couldn't find a > > > > short and descriptive name that could be used in favor of > > > > pm_runtime_put_autosuspend(). Let me throw some ideas at it and maybe > > > > you like it - or not. :-) > > > > > > I like the idea at least :-) > > > > > > > I don't know what options you guys discussed, but to me the entire > > > > "autosuspend"-suffix isn't really that necessary in my opinion. There > > > > are more ways than calling pm_runtime_put_autosuspend() that triggers > > > > us to use the RPM_AUTO flag for rpm_suspend(). For example, just > > > > calling pm_runtime_put() has the similar effect. > > > > > > To be honest, I'm lost there. pm_runtime_put() calls > > > __pm_runtime_idle(RPM_GET_PUT | RPM_ASYNC), while > > > pm_runtime_put_autosuspend() calls __pm_runtime_suspend(RPM_GET_PUT | > > > RPM_ASYNC | RPM_AUTO). > > > > __pm_runtime_idle() ends up calling rpm_idle(), which may call > > rpm_suspend() - if it succeeds to idle the device. In that case, it > > tags on the RPM_AUTO flag in the call to rpm_suspend(). Quite similar > > to what is happening when calling pm_runtime_put_autosuspend(). > > Right. > > For almost everybody, except for a small bunch of drivers that > actually have a .runtime_idle() callback, pm_runtime_put() is > literally equivalent to pm_runtime_put_autosuspend(). > > So really the question is why anyone who doesn't provide a > .runtime_idle() callback bothers with using this special > pm_runtime_put_autosuspend() thing, which really means "do a > runtime_put(), but skip my .runtime_idle() callback". My guess is that it's in most cases a legacy pattern that is being followed. Also note that rpm_idle() didn't "always" tag on the RPM_AUTO flag, even if it's quite a while ago (2013) since we added it. Unless there is some actual optimization involved, as it also allows us to skip calling rpm_idle() and go directly for rpm_suspend(). > > > > > > > > > > > > Moreover, it's similar for pm_runtime_mark_last_busy(), it's called > > > > during rpm_resume() too, for example. So why bother about having > > > > "mark_last_busy" in the new name too. > > > > > > > > That said, my suggestion is simply "pm_runtime_put_suspend". > > > > > > Can we do even better, and make pm_runtime_put() to handle autosuspend > > > automatically when autosuspend is enabled ? > > > > As stated above, this is already the case. > > What really is needed appears to be a combination of > pm_runtime_mark_last_busy() with pm_runtime_put(). This makes sense to me too, but I don't think we should limit it to this. Making pm_runtime_put_autosuspend (or if the name "pm_runtime_put_suspend" is better?) to do the similar thing, is probably a good idea too. At least in my opinion. > > Granted, pm_runtime_put() could do the pm_runtime_mark_last_busy() > thing automatically if autosuspend is enabled and the only consequence > of it might be delaying a suspend of the device until its autosuspend > timer expires, which should not be a problem in the vast majority of > cases. Right. I guess we should expect the *sync* variants to be used, if the timer really needs to be overridden. Kind regards Uffe
