From: Rafael J. Wysocki <[email protected]>
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: 21d5c57b3726 ("PM / runtime: Use device links")
Reported-by: elaine.zhang <[email protected]>
Diagnosed-by: Ulf Hansson <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
---
v1 -> v2:
* Change a function name as requested by Ulf.
* Add the R-by tag from Ulf.
* Use spin_unlock_irq()/spin_lock_irq() around the rpm_suspend_suppliers()
call in rpm_suspend().
---
drivers/base/power/runtime.c | 45 +++++++++++++++++++++++++++++++++++++------
1 file changed, 39 insertions(+), 6 deletions(-)
Index: linux-pm/drivers/base/power/runtime.c
===================================================================
--- linux-pm.orig/drivers/base/power/runtime.c
+++ linux-pm/drivers/base/power/runtime.c
@@ -305,7 +305,7 @@ static int rpm_get_suppliers(struct devi
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 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)(stru
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)(stru
|| (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 *de
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 *de
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);