Re: Question about USB shutdown procedure

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On Mon, 23 Aug 2010, Greg KH wrote:

> On Mon, Aug 23, 2010 at 08:52:36AM -0700, Sarah Sharp wrote:
> > When the system is being shutdown, what USB core functions get invoked?
> > I know that usb_hcd_pci_shutdown() will get called for the host
> > controllers, but does anything get invoked for the USB devices?
> 
> It should, do you not see that happen?
> 
> > I'm specifically wondering what we do for external hubs with devices
> > attached to them when the system is rebooted.  Does hub_disconnect() get
> > called?
> 
> It should.

This depends on what the host controller's shutdown routine does.  If 
it unregisters the root hub then disconnect processing will occur for 
all the devices below the root hub.  However I don't know that any HCDs 
do this currently.  They just disable the host controller and leave the 
bus in an idle state.

Alan Stern

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