Re: [Qemu-devel] [RFC PATCH spice v2 1/2] QXL interface: add functions to identify monitors in the guest

[Gerd Hoffmann]

On Mon, Nov 05, 2018 at 03:46:37AM -0500, Frediano Ziglio wrote:
> > 
> > > 2. Have a single function as follows:
> > > 
> > > void spice_qxl_set_device_info(QXLInstance *instance,
> > >                                const char *device_address,
> > >                                uint32_t device_display_id_start,
> > >                                uint32_t device_display_id_count);
> > 
> > How about:
> > 
> > void spice_qxl_set_device_info(QXLInstance *instance,
> >                                const char *device_address,
> >                                uint32_t device_display_id);
> > 
> > I don't think we need start+count:
> > 
> >  * For single-head devices device_display_id will be zero.
> >  * For one-channel-per-head multihead devices (i.e. virtio-gpu)
> >    device_display_id will enumerate the heads (so everybody can figure
> >    which channel is which head).
> >  * For one-channel-per-device multihead devices (i.e. qxl/linux)
> >    device_display_id will be zero too.  Number of heads is set via
> >    spice_qxl_set_max_monitors().
> > 
> > cheers,
> >   Gerd
> > 
> 
> What about "Console VNC" case? Passing a dummy (like -1) value for 
> device_display_id ?
> Kind of "I don't know which output is."

I'd use zero, assuming in case only one of multiple heads shows up as
vnc console it'll be the primary head.

But using -1 kind-of makes sense too.

cheers,
  Gerd