Ubuntu 16.04 KVM + QXL Guest - Can't change resolution

Question

Using Spice + QXL for a 16.04 guest running on a 16.04 KVM hypervisor. This was working normally until recently.

After the last reboot of the guest, resolution was set to 1024x768. When I try setting it back to 1680x1050 (or any resolution), the session freezes until the timeout reverts back to the previous resolution.

spice-vdagent and the xorg QXL driver are installed on the guest.

(edit: added additional info)

This allowed me to change the resolution, but is not persistent across reboots:

xrandr -s 1680x1050

Answer 1

I had this same issue, but I tried so many things that I am not sure what made the difference. Going in reverse of what I did to get a working solution.

1) In the KVM host, I changed the Video from "QXL" --> "VGA" (worked after this)

2) Updated ~/.config/monitors.xml with:

<monitors version="1">
  <configuration>
    <clone>no</clone>
    <output name="Virtual-0">
      <vendor>unknown</vendor>
      <product>unknown</product>
      <serial>unknown</serial>
      <width>1440</width>
      <height>900</height>
      <rate>59.990913391113281</rate>
      <x>0</x>
      <y>0</y>
      <rotation>normal</rotation>
      <reflect_x>no</reflect_x>
      <reflect_y>no</reflect_y>
      <primary>yes</primary>
      <presentation>no</presentation>
      <underscanning>no</underscanning>
    </output>
  </configuration>
  <configuration>
    <clone>no</clone>
    <output name="Virtual-0">
      <vendor>???</vendor>
      <product>0x0000</product>
      <serial>0x00000000</serial>
      <width>1440</width>
      <height>900</height>
      <rate>60</rate>
      <x>0</x>
      <y>0</y>
      <rotation>normal</rotation>
      <reflect_x>no</reflect_x>
      <reflect_y>no</reflect_y>
      <primary>yes</primary>
      <presentation>no</presentation>
      <underscanning>no</underscanning>
    </output>
  </configuration>
</monitors>

3) Updated /etc/default/grub adding: "GRUB_GFXMODE=1440x900" and then running "sudo update-grub"

4) Using advice from this post ( Reinstall package and its installed dependencies) to reinstall Gnome:

sudo apt-cache depends gnome | grep '[ |]Depends: [^<]' | cut -d: -f2 | tr -d ' ' | xargs sudo apt-get --reinstall install -y

Hope this helps!

Answer 2

The problem is in a new HWE kernel in ubuntu 16.04 (4.13).

As a workaround you can use the kernel from LTS branch (4.4), it doesn't have this problem with resolution switch on QXL and spice, and seems to work good with another QEMU virtual hardware.

sudo apt-get install linux-generic-lts-xenial
sudo apt-get purge linux-image-4.13*

Answer 3

In Proxmox KVM, I am doing everything properly, have spice-vdagent installed in VM Ubuntu 20.04 LTS Desktop (gnome), but still the system won't see in display settings any extra monitor, and clicking display 2 in remote-viewer doesn't do anything.

I've seen that people have had this problem with different Ubuntu versions (ranging probably to even 16.04 LTS already then), and I have encountered that this might be problem with HWE kernel, so perhaps reinstalling to GA kernel can fix the problem:

https://stafwag.github.io/blog/blog...resolution-on-a-kvm-virtual-machine-with-qxl/

https://askubuntu.com/a/1011440/702332

I haven't tried that but I will give it a shot some day in the future.

I also reported the case here and in other places:

https://forum.proxmox.com/threads/spice-dual-monitor-from-windows-7-guest.52296/