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USB: Export suspend statistics

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This patch exports two statistics to userspace:
/sys/bus/usb/device/.../power/connected_duration
/sys/bus/usb/device/.../power/active_duration

connected_duration is the total time (in msec) that the device has
been connected.  active_duration is the total time the device has not
been suspended.  With these two statistics, tools like PowerTOP can
calculate the percentage time that a device is active, i.e. not
suspended or auto-suspended.

Users can also use the active_duration to check if a device is actually
autosuspended.  Currently, they can set power/level to auto and
power/autosuspend to a positive timeout, but there's no way to know from
userspace if a device was actually autosuspended without looking at the
dmesg output.  These statistics will be useful in creating an automated
userspace script to test autosuspend for USB devices.

Signed-off-by: Sarah Sharp <sarah.a.sharp@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Sarah Sharp
2007-12-21 16:54:15 -08:00
committed by Greg Kroah-Hartman
parent 228426edac
commit 1512300689
4 changed files with 63 additions and 1 deletions
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49
drivers/usb/core/sysfs.c
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@@ -248,6 +248,41 @@ static void remove_persist_attributes(struct device *dev)
#ifdef CONFIG_USB_SUSPEND
static ssize_t
show_connected_duration(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct usb_device *udev = to_usb_device(dev);
return sprintf(buf, "%u\n",
jiffies_to_msecs(jiffies - udev->connect_time));
}
static DEVICE_ATTR(connected_duration, S_IRUGO, show_connected_duration, NULL);
/*
* If the device is resumed, the last time the device was suspended has
* been pre-subtracted from active_duration. We add the current time to
* get the duration that the device was actually active.
*
* If the device is suspended, the active_duration is up-to-date.
*/
static ssize_t
show_active_duration(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct usb_device *udev = to_usb_device(dev);
int duration;
if (udev->state != USB_STATE_SUSPENDED)
duration = jiffies_to_msecs(jiffies + udev->active_duration);
else
duration = jiffies_to_msecs(udev->active_duration);
return sprintf(buf, "%u\n", duration);
}
static DEVICE_ATTR(active_duration, S_IRUGO, show_active_duration, NULL);
static ssize_t
show_autosuspend(struct device *dev, struct device_attribute *attr, char *buf)
{
@@ -365,12 +400,26 @@ static int add_power_attributes(struct device *dev)
rc = sysfs_add_file_to_group(&dev->kobj,
&dev_attr_level.attr,
power_group);
if (rc == 0)
rc = sysfs_add_file_to_group(&dev->kobj,
&dev_attr_connected_duration.attr,
power_group);
if (rc == 0)
rc = sysfs_add_file_to_group(&dev->kobj,
&dev_attr_active_duration.attr,
power_group);
}
return rc;
}
static void remove_power_attributes(struct device *dev)
{
sysfs_remove_file_from_group(&dev->kobj,
&dev_attr_active_duration.attr,
power_group);
sysfs_remove_file_from_group(&dev->kobj,
&dev_attr_connected_duration.attr,
power_group);
sysfs_remove_file_from_group(&dev->kobj,
&dev_attr_level.attr,
power_group);