Re: [Qemu-devel] Should new USB devices such as usb-ccid support legacy -usbdevice?

[Gerd Hoffmann <kraxel@redhat.com>]

On 05/13/11 18:47, Anthony Liguori wrote:
> On 05/13/2011 11:36 AM, Markus Armbruster wrote:
>> When Gerd qdevified USB, he kept legacy -usbdevice working (commit
>> 0958b4cc...). What about new USB devices? Should they get a legacy
>> syntax, too?

Any reason to do that?  We already have a number of devices which can be 
setup via -device only, and that is perfectly fine IMHO.  Also I don't 
want extend the legacy syntax when adding new properties for new 
features to usb devices, which will add more cases where you have to use 
-device to use new features.

>> The only existing new device is usb-ccid, and it got one in commit
>> 36707144.
>
> What keeps -usbdevice from being a light wrapper to -device such that no
> future code is needed for this?

Different command line syntax.  Each device (which needs/accepts 
parameters) has a init function to handle the -usbdevice command line, 
which basically does:

   * parse old syntax
   * usb_create()
   * qdev_set_prop_*() calls
   * qdev_init

> I know some of the names are different but presumably we could use a map
> for existing ones and pass through names for newer ones.

Just the device name is easy, there is a field in USBDeviceInfo for that 
already, and in fact "-usbdevice tablet" acts like "-device usb-tablet" 
thanks to that entry ;)

cheers,
   Gerd