On Tuesday, January 2, 2018 5:08:52 PM CET Ulf Hansson wrote:
> During system suspend, a driver may find that the wakeup setting is enabled
> for its device and therefore configures it to deliver system wakeup
> signals.
>
> Additionally, sometimes the driver and its device, relies on some further
> consumed resource, like an irqchip or a phy for example, to stay powered
> on, as to be able to deliver system wakeup signals.
>
> In general the driver deals with this, via raising an "enable count" of the
> consumed resource or via a subsystem specific API, like irq_set_irq_wake()
> or enable|disable_irq_wake() for an irqchip. However, this may not be
> sufficient in cases when the resource's device may be attached to a PM
> domain (genpd for example) or is attached to a non-trivial middle layer
> (PCI for example).
>
> To address cases like these, the existing ->dev.power.wakeup_path status
> flag is there to help. As a matter of fact, genpd already monitors the flag
> during system suspend and acts accordingly.
>
> However, so far it has not been clear, if anybody else but the PM core is
> allowed to set the ->dev.power.wakeup_path status flag, which is required
> to make this work. For this reason, let's introduce a new helper function,
> device_set_wakeup_path().
>
> Typically a driver that manages a resource needed in the wakeup path,
> should call device_set_wakeup_path() from its ->suspend() or
> ->suspend_late() callback.
>
> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> ---
> include/linux/pm_wakeup.h | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/include/linux/pm_wakeup.h b/include/linux/pm_wakeup.h
> index 4c2cba7..4238dde 100644
> --- a/include/linux/pm_wakeup.h
> +++ b/include/linux/pm_wakeup.h
> @@ -88,6 +88,11 @@ static inline bool device_may_wakeup(struct device *dev)
> return dev->power.can_wakeup && !!dev->power.wakeup;
> }
>
> +static inline void device_set_wakeup_path(struct device *dev)
> +{
> + dev->power.wakeup_path = true;
> +}
> +
> /* drivers/base/power/wakeup.c */
> extern void wakeup_source_prepare(struct wakeup_source *ws, const char *name);
> extern struct wakeup_source *wakeup_source_create(const char *name);
> @@ -174,6 +179,8 @@ static inline bool device_may_wakeup(struct device *dev)
> return dev->power.can_wakeup && dev->power.should_wakeup;
> }
>
> +static inline void device_set_wakeup_path(struct device *dev) {}
> +
> static inline void __pm_stay_awake(struct wakeup_source *ws) {}
>
> static inline void pm_stay_awake(struct device *dev) {}
>
Applied, thanks!
