diff options
author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-10-30 17:28:49 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-10-31 11:42:51 -0600 |
commit | 8c73b4288496407d91bc616df3f7c62a88356cb2 (patch) | |
tree | bcbe494732ed13c518504738fe5f79b8de41f1e2 /drivers/base | |
parent | 9ed9895370aedd6032af2a9181c62c394d08223b (diff) | |
download | linux-8c73b4288496407d91bc616df3f7c62a88356cb2.tar.bz2 |
PM / sleep: Make async suspend/resume of devices use device links
Make the device suspend/resume part of the core system
suspend/resume code use device links to ensure that supplier
and consumer devices will be suspended and resumed in the right
order in case of async suspend/resume.
The idea, roughly, is to use dpm_wait() to wait for all consumers
before a supplier device suspend and to wait for all suppliers
before a consumer device resume.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base')
-rw-r--r-- | drivers/base/power/main.c | 85 |
1 files changed, 79 insertions, 6 deletions
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 420914061405..04bcb11ed8de 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -246,6 +246,62 @@ static void dpm_wait_for_children(struct device *dev, bool async) device_for_each_child(dev, &async, dpm_wait_fn); } +static void dpm_wait_for_suppliers(struct device *dev, bool async) +{ + struct device_link *link; + int idx; + + idx = device_links_read_lock(); + + /* + * If the supplier goes away right after we've checked the link to it, + * we'll wait for its completion to change the state, but that's fine, + * because the only things that will block as a result are the SRCU + * callbacks freeing the link objects for the links in the list we're + * walking. + */ + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) + if (READ_ONCE(link->status) != DL_STATE_DORMANT) + dpm_wait(link->supplier, async); + + device_links_read_unlock(idx); +} + +static void dpm_wait_for_superior(struct device *dev, bool async) +{ + dpm_wait(dev->parent, async); + dpm_wait_for_suppliers(dev, async); +} + +static void dpm_wait_for_consumers(struct device *dev, bool async) +{ + struct device_link *link; + int idx; + + idx = device_links_read_lock(); + + /* + * The status of a device link can only be changed from "dormant" by a + * probe, but that cannot happen during system suspend/resume. In + * theory it can change to "dormant" at that time, but then it is + * reasonable to wait for the target device anyway (eg. if it goes + * away, it's better to wait for it to go away completely and then + * continue instead of trying to continue in parallel with its + * unregistration). + */ + list_for_each_entry_rcu(link, &dev->links.consumers, s_node) + if (READ_ONCE(link->status) != DL_STATE_DORMANT) + dpm_wait(link->consumer, async); + + device_links_read_unlock(idx); +} + +static void dpm_wait_for_subordinate(struct device *dev, bool async) +{ + dpm_wait_for_children(dev, async); + dpm_wait_for_consumers(dev, async); +} + /** * pm_op - Return the PM operation appropriate for given PM event. * @ops: PM operations to choose from. @@ -490,7 +546,7 @@ static int device_resume_noirq(struct device *dev, pm_message_t state, bool asyn if (!dev->power.is_noirq_suspended) goto Out; - dpm_wait(dev->parent, async); + dpm_wait_for_superior(dev, async); if (dev->pm_domain) { info = "noirq power domain "; @@ -620,7 +676,7 @@ static int device_resume_early(struct device *dev, pm_message_t state, bool asyn if (!dev->power.is_late_suspended) goto Out; - dpm_wait(dev->parent, async); + dpm_wait_for_superior(dev, async); if (dev->pm_domain) { info = "early power domain "; @@ -752,7 +808,7 @@ static int device_resume(struct device *dev, pm_message_t state, bool async) goto Complete; } - dpm_wait(dev->parent, async); + dpm_wait_for_superior(dev, async); dpm_watchdog_set(&wd, dev); device_lock(dev); @@ -1040,7 +1096,7 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a if (dev->power.syscore || dev->power.direct_complete) goto Complete; - dpm_wait_for_children(dev, async); + dpm_wait_for_subordinate(dev, async); if (dev->pm_domain) { info = "noirq power domain "; @@ -1187,7 +1243,7 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as if (dev->power.syscore || dev->power.direct_complete) goto Complete; - dpm_wait_for_children(dev, async); + dpm_wait_for_subordinate(dev, async); if (dev->pm_domain) { info = "late power domain "; @@ -1344,6 +1400,22 @@ static int legacy_suspend(struct device *dev, pm_message_t state, return error; } +static void dpm_clear_suppliers_direct_complete(struct device *dev) +{ + struct device_link *link; + int idx; + + idx = device_links_read_lock(); + + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) { + spin_lock_irq(&link->supplier->power.lock); + link->supplier->power.direct_complete = false; + spin_unlock_irq(&link->supplier->power.lock); + } + + device_links_read_unlock(idx); +} + /** * device_suspend - Execute "suspend" callbacks for given device. * @dev: Device to handle. @@ -1360,7 +1432,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async) TRACE_DEVICE(dev); TRACE_SUSPEND(0); - dpm_wait_for_children(dev, async); + dpm_wait_for_subordinate(dev, async); if (async_error) goto Complete; @@ -1456,6 +1528,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async) spin_unlock_irq(&parent->power.lock); } + dpm_clear_suppliers_direct_complete(dev); } device_unlock(dev); |