* Ulf Hansson <ulf.hansson@xxxxxxxxxx> [220712 09:52]: > On Mon, 27 Jun 2022 at 08:13, Tony Lindgren <tony@xxxxxxxxxxx> wrote: > > > > * Ulf Hansson <ulf.hansson@xxxxxxxxxx> [220623 12:55]: > > > On Wed, 22 Jun 2022 at 07:12, Tony Lindgren <tony@xxxxxxxxxxx> wrote: > > > > > > > > We need runtime PM enabled early in probe before sdhci_setup_host() for > > > > sdhci_omap_set_capabilities(). But on the first runtime resume we must > > > > not call sdhci_runtime_resume_host() as sdhci_setup_host() has not been > > > > called yet. Let's check for an initialized controller like we already do > > > > for context restore to fix a lockdep warning. > > > > > > Thanks for explaining the background to the problem. However, looking > > > a bit closer I am worried that the error path in ->probe() is broken > > > too. > > > > > > It seems in the error path, at the label "err_rpm_put", there is a > > > call to pm_runtime_put_autosuspend(). This doesn't really guarantee > > > that the ->runtime_suspend() callback will be invoked, which I guess > > > is the assumption, don't you think? > > > > OK I'll check and send a separate patch for that. > > > > > That said, I wonder if it would not be easier to convert the ->probe() > > > function to make use of pm_runtime_get_noresume() and > > > pm_runtime_set_active() instead. In this way the ->probe() function > > > becomes responsible of turning on/off the resources "manually" that it > > > requires to probe (and when it fails to probe), while we can keep the > > > ->runtime_suspend|resume() callbacks simpler. > > > > > > Did that make sense to you? > > > > Simpler would be better :) We need to call pm_runtime_get_sync() at some > > point though to enable the parent device hierarchy. > > Is there a parent device that has runtime PM enabled? Yes there is the interconnect target module device as the parent with runtime PM enabled. So the sdhci-omap driver needs the parent enabled. > In other cases, it should be fine to use pm_runtime_set_active() > during ->probe(). Yup, this can't be done here though AFAIK. Something needs to enable runtime PM for the parent device to have the sdhci registers accessible. > > Just calling the > > sdhci_omap runtime functions is not enough. And we still need to check > > for the valid context too. Also I'm not convinced that calling > > pm_runtime_get_sync() on the parent device would do the right thing on > > old omap3 devices without bigger changes.. > > I certainly agree. The parent should not be managed directly by the > sdhci driver. OK > One thing that can be discussed though, is whether > pm_runtime_set_active() actually should runtime resume the parent, > which would make the behaviour consistent with how suppliers are being > treated. Hmm yeah that's an interesting idea. > > But maybe you have some better > > ideas that I'm not considering. > > I can try to draft a patch, if that would help? But, let's finalize > the discussion above first (apologize for the delay). OK. Should we apply the $subject patch to fix the splat meanwhile though? Seems like what you're suggesting may take some more discussion on the mailing lists. Regrads, Tony
