• Sarah Sharp's avatar
    USB: Export suspend statistics · 15123006
    Sarah Sharp authored
    This patch exports two statistics to userspace:
    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: default avatarSarah Sharp <sarah.a.sharp@intel.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
hub.c 88.5 KB