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    USB: keep count of unsuspended children · ee49fb5d
    Alan Stern 提交于
    This patch (as818b) simplifies autosuspend processing by keeping track
    of the number of unsuspended children of each USB hub.  This will
    permit us to avoid a good deal of unnecessary work all the time; we
    will no longer have to create a bunch of workqueue entries to carry
    out autosuspend requests, only to have them fail because one of the
    hub's children isn't suspended.
    
    The basic idea is simple.  There already is a usage counter in the
    usb_device structure for preventing autosuspends.  The patch just
    increments that counter for every unsuspended child.  There's only one
    tricky part: When a device disconnects we need to remember whether it
    was suspended at the time (leave the counter alone) or not (decrement
    the counter).
    Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
    Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
    ee49fb5d
driver.c 42.7 KB