Existing runtime PM ftrace events (`rpm_suspend`, `rpm_resume`,
`rpm_return_int`) offer limited visibility into the exact timing of device
runtime power state transitions, particularly when asynchronous operations
are involved. When the `rpm_suspend` or `rpm_resume` functions are invoked
with the `RPM_ASYNC` flag, a return value of 0 i.e., success merely
indicates that the device power state request has been queued, not that
the device has yet transitioned.
A new ftrace event, `rpm_status`, is introduced. This event directly logs
the `power.runtime_status` value of a device whenever it changes providing
granular tracking of runtime power state transitions regardless of
synchronous or asynchronous `rpm_suspend` / `rpm_resume` usage.
Signed-off-by: Vilas Bhat <vilasb...@google.com>
---
drivers/base/power/runtime.c | 1 +
include/trace/events/rpm.h | 36 ++++++++++++++++++++++++++++++++++++
2 files changed, 37 insertions(+)
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 05793c9fbb84..d10354847878 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -94,6 +94,7 @@ static void update_pm_runtime_accounting(struct device *dev)
static void __update_runtime_status(struct device *dev, enum rpm_status status)
{
update_pm_runtime_accounting(dev);
+ trace_rpm_status(dev, status);
dev->power.runtime_status = status;
}
diff --git a/include/trace/events/rpm.h b/include/trace/events/rpm.h
index 3c716214dab1..f1dc4e95dbce 100644
--- a/include/trace/events/rpm.h
+++ b/include/trace/events/rpm.h
@@ -101,6 +101,42 @@ TRACE_EVENT(rpm_return_int,
__entry->ret)
);
+#define RPM_STATUS_STRINGS \
+ { RPM_INVALID, "RPM_INVALID" }, \
+ { RPM_ACTIVE, "RPM_ACTIVE" }, \
+ { RPM_RESUMING, "RPM_RESUMING" }, \
+ { RPM_SUSPENDED, "RPM_SUSPENDED" }, \
+ { RPM_SUSPENDING, "RPM_SUSPENDING" }
+
+/*
+ * ftrace's __print_symbolic requires that all enum values be wrapped in the
+ * TRACE_DEFINE_ENUM macro so that the enum value can be encoded in the ftrace
+ * ring buffer.
+ */
+TRACE_DEFINE_ENUM(RPM_INVALID);
+TRACE_DEFINE_ENUM(RPM_ACTIVE);
+TRACE_DEFINE_ENUM(RPM_RESUMING);
+TRACE_DEFINE_ENUM(RPM_SUSPENDED);
+TRACE_DEFINE_ENUM(RPM_SUSPENDING);
+
+TRACE_EVENT(rpm_status,
+ TP_PROTO(struct device *dev, enum rpm_status status),
+ TP_ARGS(dev, status),
+
+ TP_STRUCT__entry(
+ __string(name, dev_name(dev))
+ __field(int, status)
+ ),
+
+ TP_fast_assign(
+ __assign_str(name, dev_name(dev));
+ __entry->status = status;
+ ),
+
+ TP_printk("%s status=%s", __get_str(name),
+ __print_symbolic(__entry->status, RPM_STATUS_STRINGS))
+);
+
#endif /* _TRACE_RUNTIME_POWER_H */
/* This part must be outside protection */
--
2.44.0.rc0.258.g7320e95886-goog
