On Thursday, November 06, 2014 09:36:46 AM Krzysztof Kozlowski wrote:
> Some drivers (e.g. bus drivers) may want to check if power.irq_safe was
> called by child driver, regardless of CONFIG_PM_RUNTIME.
>
> An example scenario is amba/bus.c and dma/pl330.c drivers. The runtime
> suspend/resume callbacks in amba bus driver act differently if irq_safe
> was set by child driver (in irq_safe mode bus clock is only disabled).
>
> The pl330 driver sets irq_safe and assumes that amba bus driver will
> only disable the clock in runtime PM. So in system sleep suspend
> callback the pl330 driver unprepares the clock after calling
> pm_runtime_force_suspend().
>
> However inconsistency would appear if CONFIG_PM_RUNTIME is not set and
> child drivers do not want the irq_safe runtime PM. In such case amba bus
> driver still has to know whether child driver wanted irq_safe - by
> looking at dev->power.irq_safe field.
>
> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
> ---
> include/linux/pm.h | 2 +-
> include/linux/pm_runtime.h | 5 ++++-
> 2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/pm.h b/include/linux/pm.h
> index 383fd68aaee1..b05fa954f50d 100644
> --- a/include/linux/pm.h
> +++ b/include/linux/pm.h
> @@ -566,6 +566,7 @@ struct dev_pm_info {
> bool ignore_children:1;
> bool early_init:1; /* Owned by the PM core */
> bool direct_complete:1; /* Owned by the PM core */
> + unsigned int irq_safe:1; /* PM runtime */
> spinlock_t lock;
> #ifdef CONFIG_PM_SLEEP
> struct list_head entry;
> @@ -590,7 +591,6 @@ struct dev_pm_info {
> unsigned int run_wake:1;
> unsigned int runtime_auto:1;
> unsigned int no_callbacks:1;
> - unsigned int irq_safe:1;
> unsigned int use_autosuspend:1;
> unsigned int timer_autosuspends:1;
> unsigned int memalloc_noio:1;
Well, that is a good reason to introduce a wrapper around power.irq_safe in my
view.
And define the wrapper so that it always returns false for CONFIG_PM_RUNTIME
unset.
This way not only you wouldn't need to move the flag from under the #ifdef,
but also you would make the compiler skip the relevant pieces of code
entiretly for CONFIG_PM_RUNTIME unset.
> diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
> index 367f49b9a1c9..d94a65662a60 100644
> --- a/include/linux/pm_runtime.h
> +++ b/include/linux/pm_runtime.h
> @@ -166,7 +166,10 @@ static inline bool pm_runtime_suspended_if_enabled(struct device *dev) { return
> static inline bool pm_runtime_enabled(struct device *dev) { return false; }
>
> static inline void pm_runtime_no_callbacks(struct device *dev) {}
> -static inline void pm_runtime_irq_safe(struct device *dev) {}
> +static inline void pm_runtime_irq_safe(struct device *dev)
> +{
> + dev->power.irq_safe = 1;
> +}
>
> static inline bool pm_runtime_callbacks_present(struct device *dev) { return false; }
> static inline void pm_runtime_mark_last_busy(struct device *dev) {}
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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