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

Mon Mar 22 15:27:18 UTC 2021

 On Monday, March 22, 2021, 10:51:48 AM EDT, Victor Toso <victortoso at redhat.com> wrote: 
 Hi,

On Mon, Mar 22, 2021 at 01:46:08PM +0000, Dr. Jennifer Nussbaum wrote:

> > I'm using virt-manger, and its related suite of stuff, to run
> > KVM/QEMU VM's on a Debian Bullseye host, which has two 4K
> > monitors. I am unable to get dual-head working at all, and I
> > can't get 4K resolution working in the way I'm apparently
> > supposed to.
>
> Can you share the vm's domain? virsh dumpxml $vm

I've posted this at the bottom of this message, with only small changes to obscure the UUID and paths.

> > I have a Debian Bullseye guest, with spice-vdagent and the QXL
> > video drivers installed in it. The Spice user manual suggests
> > that multiple-monitor support is easy; you're supposed to use a
> > Video QXL device and then everything should just work. But it
> > doesn't. Even when I increase the video memory in the XML file
> > (vgamem, I assume) to 64MB I am unable to get 4K on even a
> > single monitor using Settings -> Display on the guest; it maxes
> > out at some arbitrary-seeming thing a bit over 1980 x 1200. And
> > regardless of resolution, I also do not have a second monitor
> > available in the guest.
>
> Are you accessing with virt-manager? I don't think there is
> support for multi-monitor there? You should use virt-viewer or
> remote-viewer instead.

virt-manager uses virt-viewer natively; it's what virt-manager fires up when you use the "view graphical console" option.
Regardless, I did just launch virt-viewer separately, and it's functioning in the same way.

> > If I have a video device set to Virtio, then 4K works perfectly
> > on the guest machine; if I go to Settings -> Display there, I
> > can select 4096 x 2160, and I get lovely 4K video. However,
> > dual-head does not work. If I try to edit the XML for the video
> > device to 'heads="2"', there is no effect--at least, when I
> > restart the guest and go to Settings -> Display, there isn't an
> > option for selecting another monitor.  Could someone tell me
> > what I'm supposed to be doing?  Thank you.
> 
> Just confirming, for Spice multi-monitor [0] in recent linux
> guests, one qxl device is enough and you should set the heads to
> 2 (virsh edit $vm)
As you can see from the XML below, I do (think I) have one qxl device, with 2 heads and 64MB memory.
When I go into the guest, the maximum resolution I am offered is 2952 x 1781. And there is only one display,called "Virtual-0".
Thank you for looking this over.
Jen
----
 <domain type="kvm">  <name>debian-bullseye-test</name>  <uuid>36d7d0e7-4801-4396-9f61-2b5022xxxxxxx</uuid>  <memory unit="KiB">4194304</memory>  <currentMemory unit="KiB">4194304</currentMemory>  <vcpu placement="static">2</vcpu>  <os>    <type arch="x86_64" machine="pc-i440fx-2.8">hvm</type>    <boot dev="hd"/>  </os>  <features>    <acpi/>    <apic/>    <vmport state="off"/>  </features>  <cpu mode="host-model" check="partial"/>  <clock offset="utc">    <timer name="rtc" tickpolicy="catchup"/>    <timer name="pit" tickpolicy="delay"/>    <timer name="hpet" present="no"/>  </clock>  <on_poweroff>destroy</on_poweroff>  <on_reboot>restart</on_reboot>  <on_crash>restart</on_crash>  <pm>    <suspend-to-mem enabled="no"/>    <suspend-to-disk enabled="no"/>  </pm>  <devices>    <emulator>/usr/bin/kvm</emulator>    <disk type="file" device="disk">      <driver name="qemu" type="qcow2"/>      <source file="/home/user/VMs/debian-bullseye-clone.qcow2"/>      <target dev="vda" bus="virtio"/>      <address type="pci" domain="0x0000" bus="0x00" slot="0x07" function="0x0"/>    </disk>    <disk type="file" device="cdrom">      <driver name="qemu" type="raw"/>      <target dev="hda" bus="ide"/>      <readonly/>      <address type="drive" controller="0" bus="0" target="0" unit="0"/>    </disk>    <controller type="usb" index="0" model="ich9-ehci1">      <address type="pci" domain="0x0000" bus="0x00" slot="0x05" function="0x7"/>    </controller>    <controller type="usb" index="0" model="ich9-uhci1">      <master startport="0"/>      <address type="pci" domain="0x0000" bus="0x00" slot="0x05" function="0x0" multifunction="on"/>    </controller>    <controller type="usb" index="0" model="ich9-uhci2">      <master startport="2"/>      <address type="pci" domain="0x0000" bus="0x00" slot="0x05" function="0x1"/>    </controller>    <controller type="usb" index="0" model="ich9-uhci3">      <master startport="4"/>      <address type="pci" domain="0x0000" bus="0x00" slot="0x05" function="0x2"/>    </controller>    <controller type="pci" index="0" model="pci-root"/>    <controller type="ide" index="0">      <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x1"/>    </controller>    <controller type="virtio-serial" index="0">      <address type="pci" domain="0x0000" bus="0x00" slot="0x06" function="0x0"/>    </controller>    <interface type="network">      <mac address="52:54:00:30:01:2b"/>      <source network="default"/>      <model type="rtl8139"/>      <address type="pci" domain="0x0000" bus="0x00" slot="0x03" function="0x0"/>    </interface>    <serial type="pty">      <target type="isa-serial" port="0">        <model name="isa-serial"/>      </target>    </serial>    <console type="pty">      <target type="serial" port="0"/>    </console>    <channel type="unix">      <target type="virtio" name="org.qemu.guest_agent.0"/>      <address type="virtio-serial" controller="0" bus="0" port="1"/>    </channel>    <channel type="spicevmc">      <target type="virtio" name="com.redhat.spice.0"/>      <address type="virtio-serial" controller="0" bus="0" port="2"/>    </channel>    <input type="tablet" bus="usb">      <address type="usb" bus="0" port="1"/>    </input>    <input type="mouse" bus="ps2"/>    <input type="keyboard" bus="ps2"/>    <graphics type="spice" autoport="yes">      <listen type="address"/>      <image compression="off"/>    </graphics>    <sound model="ich6">      <address type="pci" domain="0x0000" bus="0x00" slot="0x04" function="0x0"/>    </sound>    <video>      <model type="qxl" ram="65536" vram="65536" vgamem="65536" heads="2" primary="yes"/>      <address type="pci" domain="0x0000" bus="0x00" slot="0x09" function="0x0"/>    </video>    <redirdev bus="usb" type="spicevmc">      <address type="usb" bus="0" port="2"/>    </redirdev>    <redirdev bus="usb" type="spicevmc">      <address type="usb" bus="0" port="3"/>    </redirdev>    <memballoon model="virtio">      <address type="pci" domain="0x0000" bus="0x00" slot="0x08" function="0x0"/>    </memballoon>  </devices></domain>

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