Introduce pm_runtime_get_noidle to for situations where it is not
desireable to touch an idling device. One use scenario is periodic
hangchecks performed by the drm/i915 driver which can be omitted
on a device in a runtime idle state.
v2:
- Fix inconsistent return value when !CONFIG_PM.
- Update documentation for bool return value
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Reported-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Cc: linux-pm@xxxxxxxxxxxxxxx
---
Documentation/power/runtime_pm.txt | 4 ++++
include/linux/pm_runtime.h | 6 ++++++
2 files changed, 10 insertions(+)
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt
index 0784bc3..a0cbfe1 100644
--- a/Documentation/power/runtime_pm.txt
+++ b/Documentation/power/runtime_pm.txt
@@ -363,6 +363,10 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h:
void pm_runtime_get_noresume(struct device *dev);
- increment the device's usage counter
+ bool pm_runtime_get_noidle(struct device *dev);
+ - increment the device's usage counter if it is not 0 and return
+ whether usage counter was incremented
+
int pm_runtime_get(struct device *dev);
- increment the device's usage counter, run pm_request_resume(dev) and
return its result
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
index 3bdbb41..8f429bc 100644
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -66,6 +66,11 @@ static inline void pm_runtime_get_noresume(struct device *dev)
atomic_inc(&dev->power.usage_count);
}
+static inline bool pm_runtime_get_noidle(struct device *dev)
+{
+ return atomic_add_unless(&dev->power.usage_count, 1, 0) > 0;
+}
+
static inline void pm_runtime_put_noidle(struct device *dev)
{
atomic_add_unless(&dev->power.usage_count, -1, 0);
@@ -153,6 +158,7 @@ static inline void pm_runtime_forbid(struct device *dev) {}
static inline bool pm_children_suspended(struct device *dev) { return false; }
static inline void pm_runtime_get_noresume(struct device *dev) {}
+static inline bool pm_runtime_get_noidle(struct device *dev) { return true; }
static inline void pm_runtime_put_noidle(struct device *dev) {}
static inline bool device_run_wake(struct device *dev) { return false; }
static inline void device_set_run_wake(struct device *dev, bool enable) {}
--
2.4.3
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