Messages in this thread | | | Date | Tue, 29 Sep 2015 10:39:20 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [PATCH v5 1/2] PM / sleep: Go direct_complete if driver has no callbacks |
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On Tue, 29 Sep 2015, Tomeu Vizoso wrote:
> If a suitable prepare callback cannot be found for a given device and > its driver has no PM callbacks at all, assume that it can go direct to > complete when the system goes to sleep. > > The reason for this is that there's lots of devices in a system that do > no PM at all and there's no reason for them to prevent their ancestors > to do direct_complete if they can support it. > > Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> +void device_check_pm_callbacks(struct device *dev) > +{ > + dev->power.no_pm_callbacks = > + (!dev->bus || pm_ops_is_empty(dev->bus->pm)) && > + (!dev->class || pm_ops_is_empty(dev->class->pm)) && > + (!dev->type || pm_ops_is_empty(dev->type->pm)) && > + (!dev->pm_domain || pm_ops_is_empty(&dev->pm_domain->ops)) && > + (!dev->driver || pm_ops_is_empty(dev->driver->pm)); > +}
One fairly minor point: You should lock dev->power.lock before setting this bitfield. This is because bitfields are not SMP-safe.
Alan Stern
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