Re: Question about expected behavior when PM runtime is disabled

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Friday, June 17, 2011, Alan Stern wrote:
> On Tue, 14 Jun 2011, Rafael J. Wysocki wrote:
> 
> > > Then you suggest:
> > > 
> > > 	Call pm_runtime_disable after .suspend;
> > > 
> > > 	Call pm_runtime_get_noresume and pm_runtime_enable before
> > > 	.resume;
> > > 
> > > 	Call pm_runtime_put_sync after .complete.
> > > 
> > > Right?
> > 
> > Yes, that would be resonable IMO.
> 
> This turns out to be harder than it looks.  If an error occurs, we may
> run the complete callback for devices that never were suspended or
> resumed and hence never had their usage_count incremented.  How can we
> tell that we need to skip the pm_runtime_put_sync for these devices?
> 
> Would it be okay to call pm_runtime_put_sync immediately after the
> resume callback instead of after complete?

Yes, it would.

That said we may be better off by simply reverting commit
e8665002477f0278f84f898145b1f141ba26ee26 (PM: Allow pm_runtime_suspend() to
succeed during system suspend).

Thanks,
Rafael