On Wed, Jun 29, 2016 at 10:02:42AM -0400, Alan Stern wrote: > On Wed, 29 Jun 2016, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > > > > Arjan reports that it takes a relatively long time to enable runtime > > PM for multiple devices at system startup, because all writes to the > > "control" attribute in sysfs are handled synchronously and if the > > device is suspended as a result of the write, it will block until > > that operation is complete. > > > > That may be avoided by passing the RPM_ASYNC flag to rpm_idle() > > in pm_runtime_allow() which will make it execute the device's > > "idle" callback asynchronously, so writes to "control" changing > > it from "on" to "auto" will return without waiting.
Looks like pm_runtime_allow() can now be added to the section "It is safe to execute the following helper functions from interrupt context" in Documentation/power/runtime_pm.txt. Best regards, Lukas > > > > Reported-by: Arjan van de Ven <ar...@linux.intel.com> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > > --- > > drivers/base/power/runtime.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > Index: linux-pm/drivers/base/power/runtime.c > > =================================================================== > > --- linux-pm.orig/drivers/base/power/runtime.c > > +++ linux-pm/drivers/base/power/runtime.c > > @@ -1256,7 +1256,7 @@ void pm_runtime_allow(struct device *dev > > > > dev->power.runtime_auto = true; > > if (atomic_dec_and_test(&dev->power.usage_count)) > > - rpm_idle(dev, RPM_AUTO); > > + rpm_idle(dev, RPM_AUTO | RPM_ASYNC); > > > > out: > > spin_unlock_irq(&dev->power.lock); > > Acked-by: Alan Stern <st...@rowland.harvard.edu>
