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| author | Sarah Sharp <saharabeara@gmail.com> | 2007-12-21 16:54:15 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-02-01 14:35:00 -0800 |
| commit | 1512300689426cb98bfd7e567ee9fdfaaf61b7c7 (patch) | |
| tree | a275493675fe7bc6b666d1c6a8179e103c7a199c /drivers/usb/core/usb.c | |
| parent | 228426edac844a2c9270528e9cd7ab6260ef7628 (diff) | |
| download | lwn-1512300689426cb98bfd7e567ee9fdfaaf61b7c7.tar.gz lwn-1512300689426cb98bfd7e567ee9fdfaaf61b7c7.zip | |
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>
Diffstat (limited to 'drivers/usb/core/usb.c')
| -rw-r--r-- | drivers/usb/core/usb.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c index bc5edacb0c34..fdb444d81271 100644 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -339,6 +339,8 @@ usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port1) mutex_init(&dev->pm_mutex); INIT_DELAYED_WORK(&dev->autosuspend, usb_autosuspend_work); dev->autosuspend_delay = usb_autosuspend_delay * HZ; + dev->connect_time = jiffies; + dev->active_duration = -jiffies; #endif if (root_hub) /* Root hub always ok [and always wired] */ dev->authorized = 1; |