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

[Rafael J. Wysocki]

On Tuesday, January 26, 2016 03:52:23 PM Tony Lindgren wrote:
> * Rafael J. Wysocki <rafael at kernel.org> [160126 15:38]:
> > On Wed, Jan 27, 2016 at 12:22 AM, Tony Lindgren <tony at atomide.com> wrote:
> > > * Rafael J. Wysocki <rafael at kernel.org> [160126 15:15]:
> > >> On Tue, Jan 26, 2016 at 11:48 PM, Tony Lindgren <tony at atomide.com> wrote:
> > >> > Hi,
> > >> >
> > >> > Looks like commit 5de85b9d57ab ("PM / runtime: Re-init runtime
> > >> > PM states at probe error and driver unbind") broke PM on at least
> > >> > omap3. It seems we now need to additionally also call
> > >> > pm_runtime_dont_use_autosuspend() to get things working again?
> > >> >
> > >> > The following fixes idling on omap3, but I'm wondering if we
> > >> > should do something in pm_runtime_reinit() instead?
> > >>
> > >> Well, does it actually help if you add
> > >> pm_runtime_dont_use_autosuspend(dev) to pm_runtime_reinit()?
> > >
> > > No adding it to pm_runtime_reinit() does not help.
> > 
> > Yes, I realized that it wouldn't help only after sending the previous
> > message, sorry about that.
> >
> > The reason why it helps in the driver code seems to be that
> > autosuspend_delay happens to be negative, so update_autosuspend()
> > decrements the usage counter that would have stayed incremented
> > otherwise.  Or at least that's the only way it can help I see ATM.
> 
> Oh OK.
> 
> > > Looks like we have RPM_ACTIVE set in pm_runtime_reinit() if that
> > > gives any clues.
> > 
> > It looks like pm_runtime_reinit() should clear the usage counter too.
> 
> Yeah if we do this when !pm_runtime_enabled(dev) it seems it's
> safe to pretty much reset everything?

Not only safe, but also a good idea apparently. :-)

Thanks,
Rafael