On Thursday, July 28, 2011, jean.pihet@xxxxxxxxxxxxxx wrote:
> 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);
I'd call this function "dev_pm_qos_constraints_destroy()" (and the previous
one "dev_pm_qos_constraints_init()" for consistency).
> 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;
You could avoid adding this field if there were a PM_QOS_UNINITIALIZED
(or PM_QOS_UNKNOWN) type.
And if you _really_ want to have a separate field, why don't you put it
into latency_constraints ?
> +}
> +
> +/* 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;
>
Thanks,
Rafael
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