On Tue, 19 Oct 2010 tlinder@xxxxxxxxxxxxxx wrote:
> >> +/**
> >> + * dummy_address_device() - Assign an address for the connected
> >> + * device
> >> + * @param hcd - host controller of the device
> >> + * @param udev - device to address
> >> + *
> >> + * @return int - 0 on success, or an error code (refer to
> >> + * errno-base.h for details)
> >> + *
> >> + * Issue an Address Device command (which will issue a
> >> + * SetAddress request to the device). We should be protected by
> >> + * the usb_address0_mutex in khubd's hub_port_init, so we should
> >> + * only issue and wait on one address command at the same time.
> >> + *
> >> + * This function is used only for SS hcd drivers.
> >> + */
> >> +static int dummy_address_device(struct usb_hcd *hcd, struct usb_device
> >> *udev)
> >> +{
> >> + udev->devnum = 3;
> >> + return usb_control_msg(udev, (PIPE_CONTROL << 30),
> >> + USB_REQ_SET_ADDRESS, 0, udev->devnum, 0,
> >> + NULL, 0, USB_CTRL_SET_TIMEOUT);
> >> +}
> >
> > This looks very suspicious. Why have this function if it's only going
> > to do the same thing that usbcore would do if it weren't present?
>
> Upon new device connection the host addresses the device from
> hub_set_address() that if the address_device cb was provided for the hcd -
> calls it. This function begins with a verification that either this cb was
> supplied or the usbcore already addresses the device (meaning udev->devnum
> > 1).
> usbcore addresses the device in choose_address() that is called from
> hub_port_connect_change but only if it's not a SuperSpeed hcd:
> if (!(hcd->driver->flags & HCD_USB3)) {
> /* set the address */
> choose_address(udev);
> ...
> }
> Since our hcd is SuperSpeed, choose_address() isn't called and
> udev->devnum remains 0.
> Due to the above in order for this implementation to work properly we have
> to provide the address_device cb for a SuperSpeed hcd.
> Perhaps this was already fixed but I'm not familiar with such patch. I
> would be happy to pick it up if you could refer me to it.
http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/gregkh-07-usb/usb-core-use-kernel-assigned-address-for-devices-under-xhci.patch
> > Also, the address_device routine should not change udev->devnum. The
> > code that does this in the xhci driver is being removed, because it
> > causes bugs.
>
> A better solution might be to call choose_address() for SuperSpeed hcd as
> well. If that sounds good to everyone I can make the change.
The patch listed above already contains these changes.
Alan Stern
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
