USB: Export suspend statistics
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>
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index cc93aa9..53fe049 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1034,8 +1034,10 @@
if (udev->children[i])
recursively_mark_NOTATTACHED(udev->children[i]);
}
- if (udev->state == USB_STATE_SUSPENDED)
+ if (udev->state == USB_STATE_SUSPENDED) {
udev->discon_suspended = 1;
+ udev->active_duration -= jiffies;
+ }
udev->state = USB_STATE_NOTATTACHED;
}
@@ -1084,6 +1086,12 @@
else
device_init_wakeup(&udev->dev, 0);
}
+ if (udev->state == USB_STATE_SUSPENDED &&
+ new_state != USB_STATE_SUSPENDED)
+ udev->active_duration -= jiffies;
+ else if (new_state == USB_STATE_SUSPENDED &&
+ udev->state != USB_STATE_SUSPENDED)
+ udev->active_duration += jiffies;
udev->state = new_state;
} else
recursively_mark_NOTATTACHED(udev);