Messages in this thread | | | Date | Sun, 4 Oct 2015 17:16:21 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH v5 1/2] PM / sleep: Go direct_complete if driver has no callbacks |
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On Tue 2015-09-29 14:29:19, 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.
Dunno. This sounds like asking for trouble. Even if most devices can handle this, is not this bound to introduce some bugs?
Thanks, Pavel
> > Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> > --- > > Changes in v5: > - Check for all dev_pm_ops instances associated to a device, updating a > no_pm_callbacks flag at the times when that could change. > > drivers/base/dd.c | 3 ++ > drivers/base/power/domain.c | 5 ++++ > drivers/base/power/main.c | 69 ++++++++++++++++++++++++++++++++------------- > drivers/base/power/power.h | 2 ++ > include/linux/pm.h | 1 + > 5 files changed, 61 insertions(+), 19 deletions(-) > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > index be0eb4639128..fe0e9cb684b8 100644 > --- a/drivers/base/dd.c > +++ b/drivers/base/dd.c > @@ -205,6 +205,8 @@ static void driver_bound(struct device *dev) > > klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices); > > + device_check_pm_callbacks(dev); > + > /* > * Make sure the device is no longer in one of the deferred lists and > * kick off retrying all pending devices > @@ -695,6 +697,7 @@ static void __device_release_driver(struct device *dev) > dev->pm_domain->dismiss(dev); > > klist_remove(&dev->p->knode_driver); > + device_check_pm_callbacks(dev); > if (dev->bus) > blocking_notifier_call_chain(&dev->bus->p->bus_notifier, > BUS_NOTIFY_UNBOUND_DRIVER, > diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c > index 16550c63d611..3cae1aa1885b 100644 > --- a/drivers/base/power/domain.c > +++ b/drivers/base/power/domain.c > @@ -20,6 +20,8 @@ > #include <linux/suspend.h> > #include <linux/export.h> > > +#include "power.h" > + > #define GENPD_RETRY_MAX_MS 250 /* Approximate */ > > #define GENPD_DEV_CALLBACK(genpd, type, callback, dev) \ > @@ -1305,6 +1307,7 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, > > list_add_tail(&gpd_data->base.list_node, &genpd->dev_list); > > + device_check_pm_callbacks(dev); > out: > mutex_unlock(&genpd->lock); > > @@ -1369,6 +1372,8 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd, > > genpd_free_dev_data(dev, gpd_data); > > + device_check_pm_callbacks(dev); > + > return 0; > > out: > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c > index 1710c26ba097..b6eaa00b2540 100644 > --- a/drivers/base/power/main.c > +++ b/drivers/base/power/main.c > @@ -117,6 +117,31 @@ void device_pm_unlock(void) > mutex_unlock(&dpm_list_mtx); > } > > +static bool pm_ops_is_empty(const struct dev_pm_ops *ops) > +{ > + if (!ops) > + return true; > + > + return !ops->prepare && > + !ops->suspend && > + !ops->suspend_late && > + !ops->suspend_noirq && > + !ops->resume_noirq && > + !ops->resume_early && > + !ops->resume && > + !ops->complete; > +} > + > +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)); > +} > + > /** > * device_pm_add - Add a device to the PM core's list of active devices. > * @dev: Device to add to the list. > @@ -131,6 +156,8 @@ void device_pm_add(struct device *dev) > dev_name(dev->parent)); > list_add_tail(&dev->power.entry, &dpm_list); > mutex_unlock(&dpm_list_mtx); > + > + device_check_pm_callbacks(dev); > } > > /** > @@ -1569,27 +1596,31 @@ static int device_prepare(struct device *dev, pm_message_t state) > > dev->power.wakeup_path = device_may_wakeup(dev); > > - if (dev->pm_domain) { > - info = "preparing power domain "; > - callback = dev->pm_domain->ops.prepare; > - } else if (dev->type && dev->type->pm) { > - info = "preparing type "; > - callback = dev->type->pm->prepare; > - } else if (dev->class && dev->class->pm) { > - info = "preparing class "; > - callback = dev->class->pm->prepare; > - } else if (dev->bus && dev->bus->pm) { > - info = "preparing bus "; > - callback = dev->bus->pm->prepare; > - } > + if (dev->power.no_pm_callbacks) > + ret = 1; /* Let device go direct_complete */ > + else { > + if (dev->pm_domain) { > + info = "preparing power domain "; > + callback = dev->pm_domain->ops.prepare; > + } else if (dev->type && dev->type->pm) { > + info = "preparing type "; > + callback = dev->type->pm->prepare; > + } else if (dev->class && dev->class->pm) { > + info = "preparing class "; > + callback = dev->class->pm->prepare; > + } else if (dev->bus && dev->bus->pm) { > + info = "preparing bus "; > + callback = dev->bus->pm->prepare; > + } > > - if (!callback && dev->driver && dev->driver->pm) { > - info = "preparing driver "; > - callback = dev->driver->pm->prepare; > - } > + if (!callback && dev->driver && dev->driver->pm) { > + info = "preparing driver "; > + callback = dev->driver->pm->prepare; > + } > > - if (callback) > - ret = callback(dev); > + if (callback) > + ret = callback(dev); > + } > > device_unlock(dev); > > diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h > index 998fa6b23084..518a8fc84e8d 100644 > --- a/drivers/base/power/power.h > +++ b/drivers/base/power/power.h > @@ -9,6 +9,8 @@ static inline void device_pm_init_common(struct device *dev) > } > } > > +extern void device_check_pm_callbacks(struct device *dev); > + > #ifdef CONFIG_PM > > static inline void pm_runtime_early_init(struct device *dev) > diff --git a/include/linux/pm.h b/include/linux/pm.h > index 35d599e7250d..e334b9b8cd46 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 */ > + bool no_pm_callbacks:1; /* Owned by the PM core */ > spinlock_t lock; > #ifdef CONFIG_PM_SLEEP > struct list_head entry; > -- > 2.4.3
-- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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