Re: [Qemu-devel] [PATCH 2/3] usb: add public usb_device_by_id

[Gerd Hoffmann <kraxel@redhat.com>]

> +USBDevice *usb_device_by_id(const char* id)
> +{
> +    USBBus *bus;
> +    DeviceState *qdev;
> +    USBDevice *dev;
> +
> +    QTAILQ_FOREACH(bus,&busses, next) {
> +        qdev = qdev_find_recursive(&bus->qbus, id);
> +        if (qdev != NULL) {
> +            dev = DO_UPCAST(USBDevice, qdev, qdev);
> +            return dev;
> +        }
> +    }

You don't need qdev_find_recursive here.  Have a look at the usb_info() 
code to see how to loop over all usb devices.  Then compare id with 
USBDevice->qdev.id.

cheers,
   Gerd