On Tuesday, October 15, 2013 04:43:38 PM Alan Stern wrote:
> On Tue, 15 Oct 2013, Ulf Hansson wrote:
> 
> > For devices which don't have a .runtime_idle callback or if it returns
> > 0, rpm_idle will end up in triggering a call to rpm_suspend, thus
> > trying to carry out a runtime_suspend directly from runtime_idle.
> > 
> > In the above situation we want to respect devices which has enabled
> > autosuspend, we therfore append the flag sent to rpm_suspend with
> > RPM_AUTO.
> > 
> > Do note that drivers still needs to update the device last busy mark,
> > to control the delay for this circumstance.
> > 
> > Updated runtime PM documentation accordingly.
> > 
> > Cc: Alan Stern <st...@rowland.harvard.edu>
> > Cc: Mika Westerberg <mika.westerb...@linux.intel.com>
> > Cc: Kevin Hilman <khil...@linaro.org>
> > Cc: Rob Landley <r...@landley.net>
> > Cc: Chris Ball <c...@laptop.org>
> > Cc: linux-mmc@vger.kernel.org
> > Signed-off-by: Ulf Hansson <ulf.hans...@linaro.org>
> > Acked-by: Kevin Hilman <khil...@linaro.org>
> > ---
> >  Documentation/power/runtime_pm.txt |   14 ++++++++------
> >  drivers/base/power/runtime.c       |    5 +++--
> >  2 files changed, 11 insertions(+), 8 deletions(-)
> > 
> > diff --git a/Documentation/power/runtime_pm.txt 
> > b/Documentation/power/runtime_pm.txt
> > index 71d8fe4..0f54333 100644
> > --- a/Documentation/power/runtime_pm.txt
> > +++ b/Documentation/power/runtime_pm.txt
> > @@ -145,11 +145,13 @@ The action performed by the idle callback is totally 
> > dependent on the subsystem
> >  if the device can be suspended (i.e. if all of the conditions necessary for
> >  suspending the device are satisfied) and to queue up a suspend request for 
> > the
> >  device in that case.  If there is no idle callback, or if the callback 
> > returns
> > -0, then the PM core will attempt to carry out a runtime suspend of the 
> > device;
> > -in essence, it will call pm_runtime_suspend() directly.  To prevent this 
> > (for
> > -example, if the callback routine has started a delayed suspend), the 
> > routine
> > -should return a non-zero value.  Negative error return codes are ignored 
> > by the
> > -PM core.
> > +0, then the PM core will attempt to carry out a runtime suspend of the 
> > device,
> > +also respecting devices configured for autosuspend.  In essence this means 
> > a
> > +call to pm_runtime_autosuspend() (do note that drivers needs to update the
> > +device last busy mark, pm_runtime_mark_last_busy(), to control the delay 
> > under
> > +this circumstance).  To prevent this (for example, if the callback routine 
> > has
> > +started a delayed suspend), the routine must return a non-zero value.  
> > Negative
> > +error return codes are ignored by the PM core.
> >  
> >  The helper functions provided by the PM core, described in Section 4, 
> > guarantee
> >  that the following constraints are met with respect to runtime PM 
> > callbacks for
> > @@ -308,7 +310,7 @@ drivers/base/power/runtime.c and 
> > include/linux/pm_runtime.h:
> >      - execute the subsystem-level idle callback for the device; returns an
> >        error code on failure, where -EINPROGRESS means that 
> > ->runtime_idle() is
> >        already being executed; if there is no callback or the callback 
> > returns 0
> > -      then run pm_runtime_suspend(dev) and return its result
> > +      then run pm_runtime_autosuspend(dev) and return its result
> >  
> >    int pm_runtime_suspend(struct device *dev);
> >      - execute the subsystem-level suspend callback for the device; returns 
> > 0 on
> > diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> > index 268a350..72e00e6 100644
> > --- a/drivers/base/power/runtime.c
> > +++ b/drivers/base/power/runtime.c
> > @@ -258,7 +258,8 @@ static int __rpm_callback(int (*cb)(struct device *), 
> > struct device *dev)
> >   * Check if the device's runtime PM status allows it to be suspended.  If
> >   * another idle notification has been started earlier, return immediately. 
> >  If
> >   * the RPM_ASYNC flag is set then queue an idle-notification request; 
> > otherwise
> > - * run the ->runtime_idle() callback directly.
> > + * run the ->runtime_idle() callback directly. If the ->runtime_idle 
> > callback
> > + * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO 
> > flag.
> >   *
> >   * This function must be called under dev->power.lock with interrupts 
> > disabled.
> >   */
> > @@ -331,7 +332,7 @@ static int rpm_idle(struct device *dev, int rpmflags)
> >  
> >   out:
> >     trace_rpm_return_int(dev, _THIS_IP_, retval);
> > -   return retval ? retval : rpm_suspend(dev, rpmflags);
> > +   return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
> >  }
> >  
> >  /**
> 
> Acked-by: Alan Stern <st...@rowland.harvard.edu>

I've queued up this patch for 3.13.

Thanks!

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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