diff options
Diffstat (limited to 'drivers/base/power/sysfs.c')
| -rw-r--r-- | drivers/base/power/sysfs.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c index c011ff15632..86fd9373447 100644 --- a/drivers/base/power/sysfs.c +++ b/drivers/base/power/sysfs.c @@ -54,6 +54,24 @@ * wakeup events internally (unless they are disabled), keeping * their hardware in low power modes whenever they're unused. This * saves runtime power, without requiring system-wide sleep states. + * + * async - Report/change current async suspend setting for the device + * + * Asynchronous suspend and resume of the device during system-wide power + * state transitions can be enabled by writing "enabled" to this file. + * Analogously, if "disabled" is written to this file, the device will be + * suspended and resumed synchronously. + * + * All devices have one of the following two values for power/async: + * + * + "enabled\n" to permit the asynchronous suspend/resume of the device; + * + "disabled\n" to forbid it; + * + * NOTE: It generally is unsafe to permit the asynchronous suspend/resume + * of a device unless it is certain that all of the PM dependencies of the + * device are known to the PM core. However, for some devices this + * attribute is set to "enabled" by bus type code or device drivers and in + * that cases it should be safe to leave the default value. */ static const char enabled[] = "enabled"; @@ -125,12 +143,43 @@ wake_store(struct device * dev, struct device_attribute *attr, static DEVICE_ATTR(wakeup, 0644, wake_show, wake_store); +#ifdef CONFIG_PM_SLEEP_ADVANCED_DEBUG +static ssize_t async_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + return sprintf(buf, "%s\n", + device_async_suspend_enabled(dev) ? enabled : disabled); +} + +static ssize_t async_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t n) +{ + char *cp; + int len = n; + + cp = memchr(buf, '\n', n); + if (cp) + len = cp - buf; + if (len == sizeof enabled - 1 && strncmp(buf, enabled, len) == 0) + device_enable_async_suspend(dev); + else if (len == sizeof disabled - 1 && strncmp(buf, disabled, len) == 0) + device_disable_async_suspend(dev); + else + return -EINVAL; + return n; +} + +static DEVICE_ATTR(async, 0644, async_show, async_store); +#endif /* CONFIG_PM_SLEEP_ADVANCED_DEBUG */ static struct attribute * power_attrs[] = { #ifdef CONFIG_PM_RUNTIME &dev_attr_control.attr, #endif &dev_attr_wakeup.attr, +#ifdef CONFIG_PM_SLEEP_ADVANCED_DEBUG + &dev_attr_async.attr, +#endif NULL, }; static struct attribute_group pm_attr_group = { |