Re: [Qemu-devel] paravirtual mouse/tablet

[Alon Levy <alevy@redhat.com>]

On Fri, Jan 14, 2011 at 04:13:29PM +0100, Gerd Hoffmann wrote:
>   Hi,
> 
> >So it'd end up being (x,y,pressure) N times (I think 16 is fine for
> >the foreseeable future).
> 
> I'd tend to extend MOVE to (x,y,pressure,index) and send N events
> with the same timestamp.  Needs to send only as many events as it
> finds fingers on the touchpad, i.e. usually just one or two, even if
> the protocol can easily handle alot more than 16 ;)

Doesn't that lose the coincidence? I expect mostly presses happen
sequentially (milliseconds apart maybe, but still), so probably not
an issue at all.

> 
> For a simple tablet pressure and index would just be 0.
> 
> >The details of what exactly that means
> >should be figured out by the guest driver.
> 
> Agree.
> 
> >I'm not familiar with the hardware interface, but in order to support
> >that the background interface must be a lot more complex than a
> >simple button press.
> 
> Buttons events are for buttons.  Real ones, which apple lost ;)
> 
> Of course a tap on the trackpad is usually interpreted as mouse
> click. But that is the job of the guest OS, our virtual hardware
> doesn't care.
> 
> >But then again - how would we forward fine-grained scrolling to the
> >guest if we only know that it's scrolling, but not what the actual
> >presses on the touchpad looked like? Ugh.
> 
> There must be an interface to get (more or less) the raw touchpad
> data, for apps which want implement their own multitouch gestures?
> 
> cheers,
>   Gerd
> 
>