tree 310d11b695b631c091c9f442d566400ba9a86de9
parent d25450c68767481f7c9cc4823a6da8235db40be6
author Alan Stern <stern@rowland.harvard.edu> 1164232554 -0500
committer Greg Kroah-Hartman <gregkh@suse.de> 1165011952 -0800

USB: keep count of unsuspended children

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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>