On Thursday, April 21, 2016 02:52:55 AM Laurent Pinchart wrote:
> The pm_runtime_force_suspend() and pm_runtime_force_resume() helpers are
> designed to help driver being RPM-centric by offering an easy way to
> manage runtime PM state during system suspend and resume. The first
> function will force the device into runtime suspend at system suspend
> time, while the second one will perform the reverse operation at system
> resume time.
>
> However, the pm_runtime_force_resume() really forces resume, regardless
> of whether the device was running or already suspended before the call
> to pm_runtime_force_suspend(). This results in devices being runtime
> resumed at system resume time when they shouldn't.
>
> Fix this by recording whether the device has been forcefully suspended
> in pm_runtime_force_suspend() and condition resume in
> pm_runtime_force_resume() to that state.
>
> All current users of pm_runtime_force_resume() call the function
> unconditionally in their system resume handler (some actually set it as
> the resume handler), all after calling pm_runtime_force_suspend() at
> system suspend time. The change in behaviour should thus be safe.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com>
> Reviewed-by: Kevin Hilman <khil...@baylibre.com>
Ulf, any comments?
> ---
> drivers/base/power/runtime.c | 19 ++++++++++++++++---
> include/linux/pm.h | 1 +
> 2 files changed, 17 insertions(+), 3 deletions(-)
>
> Changes since v1:
>
> - Fix typos
> - Protect the is_force_suspended flag modifications with power.lock
>
> diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> index 4c7055009bd6..8fc7fba811fa 100644
> --- a/drivers/base/power/runtime.c
> +++ b/drivers/base/power/runtime.c
> @@ -1400,6 +1400,7 @@ void pm_runtime_init(struct device *dev)
> pm_suspend_ignore_children(dev, false);
> dev->power.runtime_auto = true;
>
> + dev->power.is_force_suspended = false;
> dev->power.request_pending = false;
> dev->power.request = RPM_REQ_NONE;
> dev->power.deferred_resume = false;
> @@ -1457,6 +1458,7 @@ void pm_runtime_remove(struct device *dev)
> int pm_runtime_force_suspend(struct device *dev)
> {
> int (*callback)(struct device *);
> + unsigned long flags;
> int ret = 0;
>
> pm_runtime_disable(dev);
> @@ -1475,6 +1477,10 @@ int pm_runtime_force_suspend(struct device *dev)
> goto err;
>
> pm_runtime_set_suspended(dev);
> + spin_lock_irqsave(&dev->power.lock, flags);
> + dev->power.is_force_suspended = true;
> + spin_unlock_irqrestore(&dev->power.lock, flags);
> +
> return 0;
> err:
> pm_runtime_enable(dev);
> @@ -1483,13 +1489,13 @@ err:
> EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
>
> /**
> - * pm_runtime_force_resume - Force a device into resume state.
> + * pm_runtime_force_resume - Force a device into resume state if needed.
> * @dev: Device to resume.
> *
> * Prior invoking this function we expect the user to have brought the device
> * into low power state by a call to pm_runtime_force_suspend(). Here we
> reverse
> - * those actions and brings the device into full power. We update the
> runtime PM
> - * status and re-enables runtime PM.
> + * those actions and bring the device back to its runtime PM state before
> forced
> + * suspension. We update the runtime PM status and re-enable runtime PM.
> *
> * Typically this function may be invoked from a system resume callback to
> make
> * sure the device is put into full power state.
> @@ -1497,8 +1503,12 @@ EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
> int pm_runtime_force_resume(struct device *dev)
> {
> int (*callback)(struct device *);
> + unsigned long flags;
> int ret = 0;
>
> + if (!dev->power.is_force_suspended)
> + goto out;
> +
> callback = RPM_GET_CALLBACK(dev, runtime_resume);
>
> if (!callback) {
> @@ -1510,6 +1520,9 @@ int pm_runtime_force_resume(struct device *dev)
> if (ret)
> goto out;
>
> + spin_lock_irqsave(&dev->power.lock, flags);
> + dev->power.is_force_suspended = false;
> + spin_unlock_irqrestore(&dev->power.lock, flags);
> pm_runtime_set_active(dev);
> pm_runtime_mark_last_busy(dev);
> out:
> diff --git a/include/linux/pm.h b/include/linux/pm.h
> index 6a5d654f4447..bec15e0f244e 100644
> --- a/include/linux/pm.h
> +++ b/include/linux/pm.h
> @@ -596,6 +596,7 @@ struct dev_pm_info {
> unsigned int use_autosuspend:1;
> unsigned int timer_autosuspends:1;
> unsigned int memalloc_noio:1;
> + unsigned int is_force_suspended:1;
> enum rpm_request request;
> enum rpm_status runtime_status;
> int runtime_error;
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
