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PM: runtime: Defer suspending suppliers 

Because the PM-runtime status of the device is not updated in
__rpm_callback(), attempts to suspend the suppliers of the given
device triggered by the rpm_put_suppliers() call in there may
cause a supplier to be suspended completely before the status of
the consumer is updated to RPM_SUSPENDED, which is confusing.

To avoid that (1) modify __rpm_callback() to only decrease the
PM-runtime usage counter of each supplier and (2) make rpm_suspend()
try to suspend the suppliers after changing the consumer's status to
RPM_SUSPENDED, in analogy with the device's parent.

Link: https://lore.kernel.org/linux-pm/CAPDyKFqm06KDw_p8WXsM4dijDbho4bb6T4k50UqqvR1_COsp8g@mail.gmail.com/
Fixes: 21d5c57b37 ("PM / runtime: Use device links")
Reported-by: elaine.zhang <zhangqing@rock-chips.com>
Diagnosed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Rafael J. Wysocki 2021-03-19 15:47:31 +01:00
parent 0d02ec6b31
commit 5244f5e2d8
1 changed files with 39 additions and 6 deletions
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45
drivers/base/power/runtime.c
View File

@ -305,7 +305,7 @@ static int rpm_get_suppliers(struct device *dev)
return 0;
}
static void rpm_put_suppliers(struct device *dev)
static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend)
{
struct device_link *link;
@ -313,10 +313,30 @@ static void rpm_put_suppliers(struct device *dev)
device_links_read_lock_held()) {
while (refcount_dec_not_one(&link->rpm_active))
pm_runtime_put(link->supplier);
pm_runtime_put_noidle(link->supplier);
if (try_to_suspend)
pm_request_idle(link->supplier);
}
}
static void rpm_put_suppliers(struct device *dev)
{
__rpm_put_suppliers(dev, true);
}
static void rpm_suspend_suppliers(struct device *dev)
{
struct device_link *link;
int idx = device_links_read_lock();
list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
device_links_read_lock_held())
pm_request_idle(link->supplier);
device_links_read_unlock(idx);
}
/**
* __rpm_callback - Run a given runtime PM callback for a given device.
* @cb: Runtime PM callback to run.
@ -344,8 +364,10 @@ static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
idx = device_links_read_lock();
retval = rpm_get_suppliers(dev);
if (retval)
if (retval) {
rpm_put_suppliers(dev);
goto fail;
}
device_links_read_unlock(idx);
}
@ -368,9 +390,9 @@ static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
|| (dev->power.runtime_status == RPM_RESUMING && retval))) {
idx = device_links_read_lock();
fail:
rpm_put_suppliers(dev);
__rpm_put_suppliers(dev, false);
fail:
device_links_read_unlock(idx);
}
@ -642,8 +664,11 @@ static int rpm_suspend(struct device *dev, int rpmflags)
goto out;
}
if (dev->power.irq_safe)
goto out;
/* Maybe the parent is now able to suspend. */
if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
if (parent && !parent->power.ignore_children) {
spin_unlock(&dev->power.lock);
spin_lock(&parent->power.lock);
@ -652,6 +677,14 @@ static int rpm_suspend(struct device *dev, int rpmflags)
spin_lock(&dev->power.lock);
}
/* Maybe the suppliers are now able to suspend. */
if (dev->power.links_count > 0) {
spin_unlock_irq(&dev->power.lock);
rpm_suspend_suppliers(dev);
spin_lock_irq(&dev->power.lock);
}
out:
trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);