Re: [Qemu-devel] [PATCH v2] usb: Remove legacy -usbdevice option

[Paolo Bonzini]

On 04/01/2018 16:35, Thomas Huth wrote:
>> Well, why not, it just doesn't seem to me much simpler than
>> "-serial braille" and "-device usb-braille" :)
>
> FWIW, I think I'd also rather prefer to add some little bit of "magic"
> to "-device usb-braille" instead of introducing yet another command line
> parameter. QEMU's command line interface is already way too much
> overcrowded, so IMHO we should try to avoid new parameters if possible.

The point of deprecation is not to make the interface simpler, it is to
avoid cases where one option is doing too much and/or crossing
abstraction boundaries, for example -net creating both a device and a
hub port.

"-serial" is okay because it only creates the front-end, it's the board
that decides how to attach it to the back-end.

-usbdevice creating both a front-end and a back-end is not a problem per
se.  The issue with -usbdevice is just that it's too much code.

However, adding magic to "-device usb-braille" that creates both a
front-end and a back-end is completely the opposite of sane...

Paolo