From: Jean Pihet <j-pihet@xxxxxx>
The devices latency constraints class of PM QoS is storing the
constraints list in the device dev_pm_info struct.
This patch adds the init and de-init of the per-device constraints
list in order to support the dynamic insertion and removal
of the devices in the system.
Signed-off-by: Jean Pihet <j-pihet@xxxxxx>
---
drivers/base/power/main.c | 10 ++++------
include/linux/pm.h | 1 +
include/linux/pm_qos.h | 2 ++
kernel/pm_qos.c | 30 ++++++++++++++++++++++++++++++
4 files changed, 37 insertions(+), 6 deletions(-)
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 360c2c0..c86f97c 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -97,12 +97,8 @@ void device_pm_add(struct device *dev)
dev_name(dev->parent));
list_add_tail(&dev->power.entry, &dpm_list);
mutex_unlock(&dpm_list_mtx);
- plist_head_init(&dev->power.latency_constraints.list, &dev->power.lock);
- dev->power.latency_constraints.target_value =
- PM_QOS_DEV_LAT_DEFAULT_VALUE;
- dev->power.latency_constraints.default_value =
- PM_QOS_DEV_LAT_DEFAULT_VALUE;
- dev->power.latency_constraints.type = PM_QOS_MIN;
+ /* Call PM QoS to init the per-device latency constraints */
+ pm_qos_dev_constraints_init(dev);
}
/**
@@ -113,6 +109,8 @@ void device_pm_remove(struct device *dev)
{
pr_debug("PM: Removing info for %s:%s\n",
dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
+ /* Call PM QoS to de-init the per-device latency constraints */
+ pm_qos_dev_constraints_deinit(dev);
complete_all(&dev->power.completion);
mutex_lock(&dpm_list_mtx);
list_del_init(&dev->power.entry);
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 35e48a3..3ed53be 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -466,6 +466,7 @@ struct dev_pm_info {
void *subsys_data; /* Owned by the subsystem. */
#endif
struct pm_qos_constraints latency_constraints;
+ int latency_constraints_init;
};
extern void update_pm_runtime_accounting(struct device *dev);
diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index d72b16b..4d36537 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -63,4 +63,6 @@ int pm_qos_add_notifier(int class, struct notifier_block *notifier);
int pm_qos_remove_notifier(int class, struct notifier_block *notifier);
int pm_qos_request_active(struct pm_qos_request *req);
+void pm_qos_dev_constraints_init(struct device *dev);
+void pm_qos_dev_constraints_deinit(struct device *dev);
#endif
diff --git a/kernel/pm_qos.c b/kernel/pm_qos.c
index 7edc6d0..361fc3f 100644
--- a/kernel/pm_qos.c
+++ b/kernel/pm_qos.c
@@ -202,6 +202,9 @@ static void update_target(struct pm_qos_request *req,
WARN(1, KERN_ERR "PM QoS API called with NULL dev\n");
return;
}
+ /* Silently return if the device is being released */
+ if (!req->dev->power.latency_constraints_init)
+ return;
c = &req->dev->power.latency_constraints;
break;
case PM_QOS_CPU_DMA_LATENCY:
@@ -387,6 +390,33 @@ int pm_qos_remove_notifier(int class, struct notifier_block *notifier)
}
EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
+/* Called from the device PM subsystem at device init */
+void pm_qos_dev_constraints_init(struct device *dev)
+{
+ plist_head_init(&dev->power.latency_constraints.list, &dev->power.lock);
+ dev->power.latency_constraints.target_value =
+ PM_QOS_DEV_LAT_DEFAULT_VALUE;
+ dev->power.latency_constraints.default_value =
+ PM_QOS_DEV_LAT_DEFAULT_VALUE;
+ dev->power.latency_constraints.type = PM_QOS_MIN;
+ dev->power.latency_constraints_init = 1;
+}
+
+/* Called from the device PM subsystem at device release */
+void pm_qos_dev_constraints_deinit(struct device *dev)
+{
+ struct pm_qos_request *req, *tmp;
+
+ dev->power.latency_constraints_init = 0;
+
+ /* Flush the constraints list for the device */
+ plist_for_each_entry_safe(req, tmp,
+ &dev->power.latency_constraints.list,
+ node)
+ update_target(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
+ plist_head_init(&dev->power.latency_constraints.list, &dev->power.lock);
+}
+
static int register_pm_qos_misc(struct pm_qos_object *qos)
{
qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR;
--
1.7.2.5
--
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