Re: [RFC 2/2] usb: gadget: udc: Handle gadget_connect failure during bind operation

[Krishna Kurapati PSSNV]

On 3/22/2023 8:11 PM, Alan Stern wrote:
> On Wed, Mar 22, 2023 at 02:57:40PM +0530, Krishna Kurapati wrote:
> > In the event, gadget_connect call (which invokes pullup) fails,
> > propagate the error to udc bind operation which inturn sends the
> > error to configfs. The userspace can then retry enumeartion if
> > it chooses to.
> >
> > Signed-off-by: Krishna Kurapati <quic_kriskura@xxxxxxxxxxx>
> > ---
> >   drivers/usb/gadget/udc/core.c | 17 +++++++++++++----
> >   1 file changed, 13 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
> > index 23b0629a8774..26bfed5c3a45 100644
> > --- a/drivers/usb/gadget/udc/core.c
> > +++ b/drivers/usb/gadget/udc/core.c
> > @@ -1051,12 +1051,16 @@ EXPORT_SYMBOL_GPL(usb_gadget_set_state);
> >   
> >   /* ------------------------------------------------------------------------- */
> >   
> > -static void usb_udc_connect_control(struct usb_udc *udc)
> > +static int usb_udc_connect_control(struct usb_udc *udc)
> >   {
> > +	int ret;
> > +
> >   	if (udc->vbus)
> > -		usb_gadget_connect(udc->gadget);
> > +		ret = usb_gadget_connect(udc->gadget);
> >   	else
> > -		usb_gadget_disconnect(udc->gadget);
> > +		ret = usb_gadget_disconnect(udc->gadget);
> > +
> > +	return ret;
> >   }
> >   
> >   /**
> > @@ -1500,11 +1504,16 @@ static int gadget_bind_driver(struct device *dev)
> >   	if (ret)
> >   		goto err_start;
> >   	usb_gadget_enable_async_callbacks(udc);
> > -	usb_udc_connect_control(udc);
> > +	ret = usb_udc_connect_control(udc);
> > +	if (ret)
> > +		goto err_connect_control;
> >   
> >   	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
> >   	return 0;
> >   
> > + err_connect_control:
>
> At this point you need to copy the code in gadget_unbind_driver().  In
> particular, this should have:
>
> +	usb_gadget_disable_async_callbacks(udc);
> +	if (gadget->irq)
> +		synchronize_irq(gadget->irq);
>
> Alan Stern
>
> > +	usb_gadget_udc_stop(udc);
> > +
> >    err_start:
> >   	driver->unbind(udc->gadget);
> >   
> > --
> > 2.40.0
Hi Alan,

 Thanks for the review. Will make sure to add it in the formal patch.

Regards,
Krishna,