Hi Alan, On Friday 25 Nov 2016 10:21:21 Alan Stern wrote: > On Fri, 25 Nov 2016, Sakari Ailus wrote: > > On Thu, Nov 24, 2016 at 09:15:39PM -0500, Alan Stern wrote: > >> On Fri, 25 Nov 2016, Laurent Pinchart wrote: > >>> Dear linux-pm developers, what's the suggested way to ensure that a > >>> runtime- pm-enabled driver can run fine on a system with CONFIG_PM > >>> disabled ? > >> > >> The exact point of your question isn't entirely clear. In the most > >> literal sense, the best ways to ensure this are (1) audit the code, and > >> (2) actually try it. > >> > >> I have a feeling this doesn't quite answer your question, however. :-) > > > > The question is related to devices that require certain power-up and > > power-down sequences that are now implemented as PM runtime hooks that, > > without CONFIG_PM defined, will not be executed. Is there a better way > > than to handle this than have an implementation in the driver for the PM > > runtime and non-PM runtime case separately? > > Yes, there is a better way. For the initial power-up and final > power-down sequences, don't rely on the PM core to invoke the > callbacks. Just call them directly, yourself. > > For example, as part of the probe routine, instead of doing this: > > pm_runtime_set_suspended(dev); > pm_runtime_enable(dev); > pm_runtime_get_sync(dev); > > Do this: > > pm_runtime_set_active(dev); > pm_runtime_get_noresume(dev); > pm_runtime_enable(dev); > /* > * In case CONFIG_PM is disabled, invoke the runtime-resume > * callback directly. > */ > my_runtime_resume(dev); Wouldn't it be cleaner for drivers not to have to handle this manually (which gives an opportunity to get it wrong) but instead have pm_runtime_enable() call the runtime resume callback when CONFIG_PM is disabled ? -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
