Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 3c886c50 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
Browse files

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: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarTilman Schmidt <tilman@imap.cc>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent bc59462b

Documentation/usb/power-management.txt

+8 −0
Original line number Diff line number Diff line
@@ -278,6 +278,14 @@ optional. The methods' jobs are quite simple: 
	(although the interfaces will be in the same altsettings as

	before the suspend).



If the device is disconnected or powered down while it is suspended,

the disconnect method will be called instead of the resume or

reset_resume method.  This is also quite likely to happen when

waking up from hibernation, as many systems do not maintain suspend

current to the USB host controllers during hibernation.  (It's

possible to work around the hibernation-forces-disconnect problem by

using the USB Persist facility.)



The reset_resume method is used by the USB Persist facility (see

Documentation/usb/persist.txt) and it can also be used under certain

circumstances when CONFIG_USB_PERSIST is not enabled.  Currently, if a