[Spice-devel] Multiple monitors at 4K, in virt-manager?

[Victor Toso]

Hi,

On Tue, Mar 23, 2021 at 10:50:08AM +0000, Dr. Jennifer Nussbaum wrote:
>  On Tuesday, March 23, 2021, 04:04:27 AM EDT, Julien Rope <jrope at redhat.com> wrote:
>  
>  
>  > I still am offered only 2952 x 1781 in the guest. With those
>  > settings except 'heads="2"', it is exactly> > the same--that
>  > resolution, and only one display, "Virtual-0".> > > > As
>  > mentioned in my original message, when I use the Virtio
>  > instead of the QXL device, I do get 4K,> > though again
>  > choosing 'heads="2"' doesn't give me an additional display
>  > in the guest. (Curiously> > the one display I get is
>  > "Virtual-1" rather than "Virtual-0".) With this device
>  > there's no option for> > changing the video memory in the
>  > XML.> 
>  > 
> > The numbering (Virtual-0 vs Virtual-1) is expected - this is
> >not an issue.>   Do you actually get the choice of
> >additional displays in virt-viewer (not in the guest) ?> Under
> >the top menu "View -> Displays" you should have a list of
> >available displays. Do you see them ? Are they enabled or
> >grayed out ?

> Ah, that is some kind of progress!
> This is not visible in the integrated viewer in virt-manager,
> but when I launch virt-viewer on itsown, yes, I do get the
> option of two displays.

Although they might share some code, they are different
applications. Virt manager, AFAIK, never supported multi-monitor


> And enabling them both does allow me to launcha second display.
> I cannot then launch the display settings in the guest,
> however; it segfaults right away. I'll look into that.

The sefault happens ins virt-viewer? You can run with
--spice-debug to know what's going on and a backtrace and help
too.

> But xrandr does report two displays; the second one is 2135 x
> 1647, though. Not clear why Istill don't get a 4K option with
> QXL.

The whole multi-monitor + QXL works from the guest kernel
perspective as if another monitor is being plugged in (by QEMU) ~
so, what are you running in your Guest? The kernel version +
Desktop enviroment

> If I try this with the virtio device (instead of QXL) with two
> heads, it's similar: a separate virt-viewer instance allows me
> to launch two displays; in this case xrandr reports 4K
> displays. But as before, the display settings manager segfaults
> right away.  Exploring further.  Jen

Ah, it is the guest's display settings that segfaults. Quite odd!

Cheers,
Victor
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