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

[Gerd Hoffmann]

  Hi,

> - We're going to try to implement you suggestion of identifying the
> monitors in the guest basically according to your outline in
> https://lists.freedesktop.org/archives/spice-devel/2018-August/045465.html

Ok.  I'll stay tuned.  Cc'ing me on patches you send out would be great.

> > Another lousely related thing:  While debugging another issue I've
> > noticed that QXLMonitorsConfig has a surface_id field.  What this is
> > intended for?  Map non-primary surface to a head?
> 
> I just did a brief investigation, I am not sure. It seems the field is
> not used in the QEMU <-> SPICE part of the exchange?

qemu doesn't touch it.
current linux guest driver never sets this, so it is zero.

> In the SPICE protocol the field is used to refer to the surface on
> which the monitor is located. I think it can only be a primary surface
> and due to implementation limitations this means only surface ID 0, but
> I may be wrong here. Maybe Frediano has more insight.

Well, yes, there can be only one primary surface, and the (reserved)
surface ID for it is 0.

Question is what is supposed to happed in case the ID of another
(non-primary) surface is placed in that field?

Tried to do that:
    https://git.kraxel.org/cgit/linux/log/?h=drm-qxl-wayland-debug

Looks like it has not the desired effect in spice client ...

> > And one more:  I'm trying to get edid support into qemu and linux kms
> > drivers.  This might also help identify monitors in the guest (edid data
> > blobs can have serial numbers).  Not short-term though as this will need
> > updated guest drivers to work.
> 
> We also considered EDID as a possibility for identification, but in the
> end discarded it as not fitting well. The main reason I think was that
> EDID is actually data from the physical monitor, not a graphics device
> output.

Well, yes, passing through the edid from the physical monitor would not
work very well I guess.  I'm looking into purely virtual edid data ...

cheers,
  Gerd