Re: [PATCH] USB: remove CONFIG_USB_PERSIST from Documentation

[Alan Stern]

On Wed, 2 Jul 2014, Paul Bolle wrote:

> On Tue, 2014-06-24 at 13:19 -0400, Alan Stern wrote:
> > On Tue, 24 Jun 2014, Paul Bolle wrote:
> > > On Tue, 2014-06-24 at 10:25 -0400, Alan Stern wrote:
> > > > Also, that "Later kernels" thing has already arrived.  I believe it was 
> > > > implemented in 2.6.35.
> > > 
> > > How does the kernel currently call the disconnect method? I can't yet
> > > say for sure, and it seems silly to send a v2 dropping those lines
> > > without actually knowing why they can be dropped.
> > 
> > In drivers/usb/core/driver.c:usb_resume_complete(), which is called 
> > during the final "complete" phase of system suspend, interfaces that 
> > were marked for rebinding (because their drivers didn't have proper PM 
> > support) get rebound.
> > 
> > Is that what you wanted to know?
> 
> I haven't yet discovered what the link is between rebinding and the
> "disconnect" method. I'll have to study that. This is far from urgent,
> so that might take me quite some time.

Rebinding means unbinding followed by binding.  The disconnect method 
gets called during unbinding.  The detailed call chain is:

	usb_resume_complete ->
	rebind_marked_interfaces -> 
	usb_rebind_intf ->
	usb_forced_unbind_intf ->
	usb_driver_release_interface ->
	device_release_driver ->
	__device_release_driver ->
	usb_unbind_interface ->
	disconnect.

Alan Stern

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