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Subject[PATCH] PM-runtime: add tracepoints for usage_count changes
Add tracepoints to remaining places where device's power.usage_count
is changed. This helps debugging where and why autosuspend is prevented.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
---
drivers/base/power/runtime.c | 13 +++++++++++--
include/trace/events/rpm.h | 6 ++++++
2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 48616f358854..16134a69bf6f 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1006,8 +1006,10 @@ int __pm_runtime_idle(struct device *dev, int rpmflags)
int retval;

if (rpmflags & RPM_GET_PUT) {
- if (!atomic_dec_and_test(&dev->power.usage_count))
+ if (!atomic_dec_and_test(&dev->power.usage_count)) {
+ trace_rpm_usage_rcuidle(dev, rpmflags);
return 0;
+ }
}

might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
@@ -1038,8 +1040,10 @@ int __pm_runtime_suspend(struct device *dev, int rpmflags)
int retval;

if (rpmflags & RPM_GET_PUT) {
- if (!atomic_dec_and_test(&dev->power.usage_count))
+ if (!atomic_dec_and_test(&dev->power.usage_count)) {
+ trace_rpm_usage_rcuidle(dev, rpmflags);
return 0;
+ }
}

might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
@@ -1101,6 +1105,7 @@ int pm_runtime_get_if_in_use(struct device *dev)
retval = dev->power.disable_depth > 0 ? -EINVAL :
dev->power.runtime_status == RPM_ACTIVE
&& atomic_inc_not_zero(&dev->power.usage_count);
+ trace_rpm_usage_rcuidle(dev, 0);
spin_unlock_irqrestore(&dev->power.lock, flags);
return retval;
}
@@ -1434,6 +1439,8 @@ void pm_runtime_allow(struct device *dev)
dev->power.runtime_auto = true;
if (atomic_dec_and_test(&dev->power.usage_count))
rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
+ else
+ trace_rpm_usage_rcuidle(dev, RPM_AUTO | RPM_ASYNC);

out:
spin_unlock_irq(&dev->power.lock);
@@ -1501,6 +1508,8 @@ static void update_autosuspend(struct device *dev, int old_delay, int old_use)
if (!old_use || old_delay >= 0) {
atomic_inc(&dev->power.usage_count);
rpm_resume(dev, 0);
+ } else {
+ trace_rpm_usage_rcuidle(dev, 0);
}
}

diff --git a/include/trace/events/rpm.h b/include/trace/events/rpm.h
index 26927a560eab..3c716214dab1 100644
--- a/include/trace/events/rpm.h
+++ b/include/trace/events/rpm.h
@@ -74,6 +74,12 @@ DEFINE_EVENT(rpm_internal, rpm_idle,

TP_ARGS(dev, flags)
);
+DEFINE_EVENT(rpm_internal, rpm_usage,
+
+ TP_PROTO(struct device *dev, int flags),
+
+ TP_ARGS(dev, flags)
+);

TRACE_EVENT(rpm_return_int,
TP_PROTO(struct device *dev, unsigned long ip, int ret),
--
2.20.1
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