5de85b9d57
There are two common expectations among several subsystems/drivers that deploys runtime PM support, but which isn't met by the driver core. Expectation 1) At ->probe() the subsystem/driver expects the runtime PM status of the device to be RPM_SUSPENDED, which is the initial status being assigned at device registration. This expectation is especially common among some of those subsystems/ drivers that manages devices with an attached PM domain, as those requires the ->runtime_resume() callback at the PM domain level to be invoked during ->probe(). Moreover these subsystems/drivers entirely relies on runtime PM resources being managed at the PM domain level, thus don't implement their own set of runtime PM callbacks. These are two scenarios that suffers from this unmet expectation. i) A failed ->probe() sequence requests probe deferral: ->probe() ... pm_runtime_enable() pm_runtime_get_sync() ... err: pm_runtime_put() pm_runtime_disable() ... As there are no guarantees that such sequence turns the runtime PM status of the device into RPM_SUSPENDED, the re-trying ->probe() may start with the status in RPM_ACTIVE. In such case the runtime PM core won't invoke the ->runtime_resume() callback because of a pm_runtime_get_sync(), as it considers the device to be already runtime resumed. ii) A driver re-bind sequence: At driver unbind, the subsystem/driver's >remove() callback invokes a sequence of runtime PM APIs, to undo actions during ->probe() and to put the device into low power state. ->remove() ... pm_runtime_put() pm_runtime_disable() ... Similar as in the failing ->probe() case, this sequence don't guarantee the runtime PM status of the device to turn into RPM_SUSPENDED. Trying to re-bind the driver thus causes the same issue as when re-trying ->probe(), in the probe deferral scenario. Expectation 2) Drivers that invokes the pm_runtime_irq_safe() API during ->probe(), triggers the runtime PM core to increase the usage count for the device's parent and permanently make it runtime resumed. The usage count is only dropped at device removal, which also allows it to be runtime suspended again. A re-trying ->probe() repeats the call to pm_runtime_irq_safe() and thus once more triggers the usage count of the device's parent to be increased. This leads to not only an imbalance issue of the usage count of the device's parent, but also to keep it runtime resumed permanently even if ->probe() fails. To address these issues, let's change the policy of the driver core to meet these expectations. More precisely, at ->probe() failures and driver unbind, restore the initial states of runtime PM. Although to still allow subsystem's to control PM for devices that doesn't ->probe() successfully, don't restore the initial states unless runtime PM is disabled. Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Kevin Hilman <khilman@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
153 lines
4 KiB
C
153 lines
4 KiB
C
#include <linux/pm_qos.h>
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static inline void device_pm_init_common(struct device *dev)
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{
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if (!dev->power.early_init) {
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spin_lock_init(&dev->power.lock);
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dev->power.qos = NULL;
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dev->power.early_init = true;
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}
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}
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#ifdef CONFIG_PM
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static inline void pm_runtime_early_init(struct device *dev)
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{
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dev->power.disable_depth = 1;
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device_pm_init_common(dev);
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}
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extern void pm_runtime_init(struct device *dev);
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extern void pm_runtime_reinit(struct device *dev);
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extern void pm_runtime_remove(struct device *dev);
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struct wake_irq {
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struct device *dev;
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int irq;
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bool dedicated_irq:1;
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};
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extern void dev_pm_arm_wake_irq(struct wake_irq *wirq);
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extern void dev_pm_disarm_wake_irq(struct wake_irq *wirq);
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#ifdef CONFIG_PM_SLEEP
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extern int device_wakeup_attach_irq(struct device *dev,
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struct wake_irq *wakeirq);
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extern void device_wakeup_detach_irq(struct device *dev);
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extern void device_wakeup_arm_wake_irqs(void);
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extern void device_wakeup_disarm_wake_irqs(void);
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#else
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static inline int
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device_wakeup_attach_irq(struct device *dev,
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struct wake_irq *wakeirq)
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{
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return 0;
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}
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static inline void device_wakeup_detach_irq(struct device *dev)
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{
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}
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static inline void device_wakeup_arm_wake_irqs(void)
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{
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}
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static inline void device_wakeup_disarm_wake_irqs(void)
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{
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}
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#endif /* CONFIG_PM_SLEEP */
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/*
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* sysfs.c
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*/
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extern int dpm_sysfs_add(struct device *dev);
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extern void dpm_sysfs_remove(struct device *dev);
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extern void rpm_sysfs_remove(struct device *dev);
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extern int wakeup_sysfs_add(struct device *dev);
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extern void wakeup_sysfs_remove(struct device *dev);
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extern int pm_qos_sysfs_add_resume_latency(struct device *dev);
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extern void pm_qos_sysfs_remove_resume_latency(struct device *dev);
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extern int pm_qos_sysfs_add_flags(struct device *dev);
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extern void pm_qos_sysfs_remove_flags(struct device *dev);
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extern int pm_qos_sysfs_add_latency_tolerance(struct device *dev);
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extern void pm_qos_sysfs_remove_latency_tolerance(struct device *dev);
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#else /* CONFIG_PM */
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static inline void pm_runtime_early_init(struct device *dev)
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{
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device_pm_init_common(dev);
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}
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static inline void pm_runtime_init(struct device *dev) {}
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static inline void pm_runtime_reinit(struct device *dev) {}
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static inline void pm_runtime_remove(struct device *dev) {}
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static inline int dpm_sysfs_add(struct device *dev) { return 0; }
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static inline void dpm_sysfs_remove(struct device *dev) {}
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static inline void rpm_sysfs_remove(struct device *dev) {}
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static inline int wakeup_sysfs_add(struct device *dev) { return 0; }
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static inline void wakeup_sysfs_remove(struct device *dev) {}
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static inline int pm_qos_sysfs_add(struct device *dev) { return 0; }
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static inline void pm_qos_sysfs_remove(struct device *dev) {}
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static inline void dev_pm_arm_wake_irq(struct wake_irq *wirq)
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{
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}
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static inline void dev_pm_disarm_wake_irq(struct wake_irq *wirq)
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{
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}
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#endif
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#ifdef CONFIG_PM_SLEEP
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/* kernel/power/main.c */
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extern int pm_async_enabled;
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/* drivers/base/power/main.c */
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extern struct list_head dpm_list; /* The active device list */
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static inline struct device *to_device(struct list_head *entry)
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{
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return container_of(entry, struct device, power.entry);
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}
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extern void device_pm_sleep_init(struct device *dev);
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extern void device_pm_add(struct device *);
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extern void device_pm_remove(struct device *);
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extern void device_pm_move_before(struct device *, struct device *);
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extern void device_pm_move_after(struct device *, struct device *);
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extern void device_pm_move_last(struct device *);
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#else /* !CONFIG_PM_SLEEP */
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static inline void device_pm_sleep_init(struct device *dev) {}
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static inline void device_pm_add(struct device *dev) {}
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static inline void device_pm_remove(struct device *dev)
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{
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pm_runtime_remove(dev);
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}
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static inline void device_pm_move_before(struct device *deva,
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struct device *devb) {}
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static inline void device_pm_move_after(struct device *deva,
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struct device *devb) {}
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static inline void device_pm_move_last(struct device *dev) {}
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#endif /* !CONFIG_PM_SLEEP */
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static inline void device_pm_init(struct device *dev)
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{
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device_pm_init_common(dev);
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device_pm_sleep_init(dev);
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pm_runtime_init(dev);
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}
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