[Spice-devel] [RFC PATCH v2 00/20] Monitor ID rework

[Lukáš Hrázký]

On Fri, 2018-08-24 at 14:39 +0200, Gerd Hoffmann wrote:
>   Hi,
> 
> > > Yes, we want this for sure.  One channel per display.
> > 
> > Maybe you cut too much context. Who is "we" in the above sentence?
> > Why "we want"?
> 
> See other reply.
> 
> > > Yes.  *That* is the underlying problem.  There is no guest-visible link
> > > between display device and spice channel.  Except when the device is
> > > qxl, because qxl has a channel-id field somewhere (in qxl rom IIRC)
> > > which the guest can read.
> > > 
> > > And it is not limited to vGPU.  Try place two emulated display devices
> > > into one guest (not using qxl).  You'll face the very same issue.
> > > 
> > > Placing both channel_id and monitor_id into the messages isn't going to
> > > solve this.
> > 
> > Yes, we have 2 issues:
> > a) display_id = channel_id ? channel_id : monitor_id formula (that can
> >    be solved with channel_id and monitor_id instead of using display_id);
> 
> I'm not sure we have to solve this one.  What is the use case?  If you
> use qxl as boot display in a vgpu setup, would you seriously want
> multiple monitors on the qxl device?

Not multiple monitors on the qxl device, multiple monitors on the vGPU.
In case we do one monitor per channel, then we don't strictly need
this, that's true.

> > b) vdagent not knowing what a given display_id is.
> 
> Yes.  And I think this should be tackled for classic display channels
> too, not only streaming channels.

Do you have any idea how to do this, though? I've thought long about
this and haven't found a universal way to solve it.

Thanks,
Lukas

> cheers,
>   Gerd
> 
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