USB: power-management documenation update
This patch (as1014) was partly written by Tilman Schmidt. It clarifies the USB power-management documentation by explaining that when a disconnect occurs, a suspend method call might not be followed by either a resume or a reset_resume call. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Tilman Schmidt <tilman@imap.cc> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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@ -278,6 +278,14 @@ optional. The methods' jobs are quite simple:
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(although the interfaces will be in the same altsettings as
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before the suspend).
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If the device is disconnected or powered down while it is suspended,
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the disconnect method will be called instead of the resume or
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reset_resume method. This is also quite likely to happen when
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waking up from hibernation, as many systems do not maintain suspend
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current to the USB host controllers during hibernation. (It's
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possible to work around the hibernation-forces-disconnect problem by
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using the USB Persist facility.)
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The reset_resume method is used by the USB Persist facility (see
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Documentation/usb/persist.txt) and it can also be used under certain
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circumstances when CONFIG_USB_PERSIST is not enabled. Currently, if a
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