On Mon, 14 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 driver's still needs to update the device last busy mark, > to control the delay for this circumstance. > > Updated runtime PM documentation accordingly. > > Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > Cc: Kevin Hilman <khilman@xxxxxxxxxx> > Cc: Rob Landley <rob@xxxxxxxxxxx> > Cc: Chris Ball <cjb@xxxxxxxxxx> > Cc: linux-mmc@xxxxxxxxxxxxxxx > Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > --- > Documentation/power/runtime_pm.txt | 13 +++++++------ > drivers/base/power/runtime.c | 6 ++++-- > 2 files changed, 11 insertions(+), 8 deletions(-) > > diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt > index 71d8fe4..236d9f4 100644 > --- a/Documentation/power/runtime_pm.txt > +++ b/Documentation/power/runtime_pm.txt Note that the style in this file is to use _two_ spaces after the period at the end of each sentence. > @@ -145,11 +145,12 @@ 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 it means a call s/it/this/ > +to pm_runtime_autosuspend(). Do note that driver's still needs to update the s/driver's still needs/drivers need/ This entire sentence should be inside parentheses. > +device last busy mark (pm_runtime_mark_last_busy), to control the delay under > +this circumstance. To prevent this, the routine must return a non-zero value. Don't remove the phrase "(for example, if the callback function has started a delayed suspend)". > +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 +309,7 @@ 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..e6867d4 100644 > --- a/drivers/base/power/runtime.c > +++ b/drivers/base/power/runtime.c > @@ -258,7 +258,9 @@ 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, run rpm_suspend with RPM_AUTO flag to s/run rpm_suspend with/call rpm_suspend() with the/ > + * respect drivers using autosuspend. I think you can end the sentence after "flag". Otherwise it sounds like the only reason for calling rpm_suspend() is to respect drivers using autosuspend, which is not accurate. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
