PM regression with commit 5de85b9d57ab PM runtime re-init in v4.5-rc1

[Tony Lindgren]

* Alan Stern <stern at rowland.harvard.edu> [160202 08:17]:
> On Tue, 2 Feb 2016, Ulf Hansson wrote:
> > 
> > Your observations is correct. The hardware will be kept active
> > in-between the probe attempts (and thus also if probing fails).
> > Although, that's not a regression as that's the behaviour you get from
> > runtime PM, when drivers are implemented like omap_hsmmc.
> 
> Perhaps this is what we should do.  If probing gets deferred a few 
> times, doing runtime suspends and resumes in between will be a waste of 
> time.

That sounds like an optimization though. We'd still have to disable
the deviec somehow after deferred probe gives up.

> ?  pm_runtime_put_sync() _already_ does not respect the autosuspend 
> mode.  If you want to respect it, you have to call 
> pm_runtime_put_sync_autosuspend() instead.

I think you found the real bug there. So the right fix is to
call pm_runtime_put_sync_autosuspend() at the end of failed
probe in omap_hsmmc. Let me give that a try here.

Can we add some warning to pm_runtime_put_sync() about that?

Regards,

Tony