Re: [PATCH v9 REBASE 6/9] USB: notify phy when root hub port connect change

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On Tue, Jul 10, 2012 at 11:07:14AM -0400, Alan Stern wrote:
> On Tue, 10 Jul 2012, Richard Zhao wrote:
> 
> > On Sat, Jul 07, 2012 at 10:56:45PM +0800, Richard Zhao wrote:
> > > Phy may need to change settings when port connect change.
> > > 
> > > Signed-off-by: Richard Zhao <richard.zhao@xxxxxxxxxxxxx>
> > > Tested-by: Subodh Nijsure <snijsure@xxxxxxxxxxxx>
> > > ---
> > >  drivers/usb/core/hub.c |    8 ++++++++
> > >  1 file changed, 8 insertions(+)
> > > 
> > > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> > > index 4cc8dc9..2ba9d84 100644
> > > --- a/drivers/usb/core/hub.c
> > > +++ b/drivers/usb/core/hub.c
> > > @@ -20,6 +20,7 @@
> > >  #include <linux/usb.h>
> > >  #include <linux/usbdevice_fs.h>
> > >  #include <linux/usb/hcd.h>
> > > +#include <linux/usb/otg.h>
> > >  #include <linux/usb/quirks.h>
> > >  #include <linux/kthread.h>
> > >  #include <linux/mutex.h>
> > > @@ -4037,6 +4038,13 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
> > >  		}
> > >  	}
> > >  
> > > +	if (unlikely(hcd->phy && !hdev->parent)) {
> > > +		if (portstatus & USB_PORT_STAT_CONNECTION)
> > > +			usb_phy_notify_connect(hcd->phy, port1);
> > > +		else
> > > +			usb_phy_notify_disconnect(hcd->phy, port1);
> > There's another issue. When hcd is removed, notify disconnect is not
> > called. Is it ok, if I remove the above two line and add below patch:
> 
> You should keep those two lines, since it's possible for a disconnect
> to occur without usb_disconnect() being called.  This happens when a
> device fails to enumerate.
> 
> > --- a/drivers/usb/core/hub.c
> > +++ b/drivers/usb/core/hub.c
> > @@ -1924,6 +1924,11 @@ void usb_disconnect(struct usb_device **pdev)
> >  	 */
> >  	device_del(&udev->dev);
> >  
> > +	if (udev->parent && !udev->parent->parent) {
> > +		struct usb_hcd *hcd = bus_to_hcd(udev->bus);
> > +		usb_phy_notify_disconnect(hcd->phy, udev->portnum);
> > +	}
> 
> You might not want to add this.  usb_disconnect() can get called in 
> situations where the device remains physically connected (if the 
> firmware changes during a reset, for example).
> 
> If you want to notify the phy when the root hub is removed, there are 
> better places to do it.  One possibility is in hub_quiesce(), another 
> is in usb_remove_hcd().
Thanks. I'll need more testing, and won't add it in this patch.

Richard
> 
> Alan Stern
> 
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