Am Freitag, 27. November 2009 18:15:22 schrieb Alan Stern:
> On Thu, 26 Nov 2009, Oliver Neukum wrote:
> > Am Donnerstag, 26. November 2009 18:03:04 schrieb Alan Stern:
> > > If the interface is in the middle of binding or unbinding when the
> > > reset occurs, the driver need not have a pre_reset or post_reset
> > > method. This exception is for the drivers that do a reset within their
> > > probe routine, of which there are (or were) several. So the test has
> > > to be retained.
> >
> > This way?
> >
> > @@ -3672,6 +3673,10 @@ int usb_reset_device(struct usb_device *udev)
> > drv = to_usb_driver(cintf->dev.driver);
> > if (drv->pre_reset && drv->post_reset)
> > unbind = (drv->pre_reset)(cintf);
> > + /*
> > + * you can use usb_reset_device() from
> > + * probe() without providing reset
>
> Without providing pre_reset or post_reset. "without providing reset"
> doesn't make sense.
Roger.
> > + */
> > else if (cintf->condition ==
> > USB_INTERFACE_BOUND)
> > unbind = 1;
> > @@ -3687,17 +3692,30 @@ int usb_reset_device(struct usb_device *udev)
> > for (i = config->desc.bNumInterfaces - 1; i >= 0; --i) {
> > struct usb_interface *cintf = config->interface[i];
> > struct usb_driver *drv;
> > - int rebind = cintf->needs_binding;
> >
> > - if (!rebind && cintf->dev.driver) {
> > + if (!cintf->needs_binding && cintf->dev.driver) {
> > drv = to_usb_driver(cintf->dev.driver);
> > if (drv->post_reset)
> > - rebind = (drv->post_reset)(cintf);
> > - else if (cintf->condition ==
> > - USB_INTERFACE_BOUND)
> > - rebind = 1;
> > + cintf->needs_binding =
> > + (drv->post_reset)(cintf) ? 1 : 0;
>
> Purely as a matter of taste, it might be clearer to write this as
>
> if (drv->post_reset(cintf))
> cintf->needs_binding = 1;
>
> > + else if (cintf->condition == USB_INTERFACE_BOUND)
> > + cintf->needs_binding = 1;
>
> I think these two lines aren't needed, and in fact they weren't needed
> in the original code. The only way to reach this spot is if you are in
> the middle of binding or unbinding; hence the test can never succeed.
Roger.
> > }
> > - if (ret == 0 && rebind)
> > + }
> > +
> > + /*
> > + * Don't rebind until after all the post_reset() calls
> > + * so that a newly bound driver does not get an unbalanced
> > + * call to post_reset()
> > + */
> > + for (i = config->desc.bNumInterfaces - 1; i >= 0; --i){
> > + struct usb_interface *cintf = config->interface[i];
> > +
> > + /*
> > + * safe w.r.t. usb_claim_interface() as
> > + * that clears needs_binding
> > + */
>
> Hmm. If your probe routine claims some other interfaces and then does
> a reset, and you don't provide pre_reset and post_reset methods, you're
> likely to run into trouble anyway. Drivers just shouldn't do that.
> They should carry out the reset first.
Suppose another driver is rebound.
Regards
Oliver
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