On Fri, 14 Jan 2011, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@xxxxxxx>
>
> Currently, wakeup sysfs attributes are created for all devices,
> regardless of whether or not they are wakeup-capable. This is
> excessive and complicates wakeup device identification from user
> space (i.e. to identify wakeup-capable devices user space has to read
> /sys/devices/.../power/wakeup for all devices and see if these files
> are not empty).
>
> Fix this issue by avoiding to create wakeup sysfs files for devices
> that cannot wake up the system from sleep states (i.e. whose
> power.can_wakeup flags are unset during registration) and modify
> device_set_wakeup_capable() so that it adds (or removes) the relevant
> sysfs attributes if a device's wakeup capability status is changed.
...
> static struct attribute *runtime_attrs[] = {
> -#ifndef CONFIG_PM_ADVANCED_DEBUG
> +#ifdef CONFIG_PM_RUNTIME
> &dev_attr_runtime_status.attr,
> -#endif
> &dev_attr_control.attr,
> &dev_attr_runtime_suspended_time.attr,
> &dev_attr_runtime_active_time.attr,
> &dev_attr_autosuspend_delay_ms.attr,
> +#ifdef CONFIG_PM_ADVANCED_DEBUG
> + &dev_attr_runtime_usage.attr,
> + &dev_attr_runtime_active_kids.attr,
> + &dev_attr_runtime_enabled.attr,
> +#endif
> +#endif /* CONFIG_PM_RUNTIME */
> NULL,
> };
> static struct attribute_group pm_runtime_attr_group = {
> @@ -480,35 +485,49 @@ int dpm_sysfs_add(struct device *dev)
> int rc;
>
> rc = sysfs_create_group(&dev->kobj, &pm_attr_group);
> - if (rc == 0 && !dev->power.no_callbacks) {
> + if (rc)
> + return rc;
> +
> + if (pm_runtime_callbacks_present(dev)) {
> rc = sysfs_merge_group(&dev->kobj, &pm_runtime_attr_group);
> if (rc)
> - sysfs_remove_group(&dev->kobj, &pm_attr_group);
> + goto err_out;
> + }
One thing I don't like about this change. The original code defines
runtime_status, runtime_usage, runtime_active_kids, and runtime_enabled
whenever PM_RUNTIME and PM_ADVANCED_DEBUG are set. Now you don't
define these attributes if runtime callbacks aren't present, even
though they would still make sense. Maybe you should have two
runtime-related attribute groups, where one depends on
callbacks_present and the other doesn't.
Apart from that, it all seems reasonable. But you should change the
description of the wakeup attribute in Documentation/power/devices.txt;
it says that the attribute file is present but empty if the device is
not wakeup-capable.
Alan Stern
_______________________________________________
linux-pm mailing list
linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linux-foundation.org/mailman/listinfo/linux-pm
