I'm working on Ubuntu 22.04.5, amd64, fully patched. It provides QEMU 1:6.2+dfsg-2ubuntu6.26 and libvirt 8.0.0-1ubuntu7.11. The problem I am experiencing is, when the host machine blanks the monitor, I lose the display on the guest when I sit back down at the computer and wake the monitor. The error message (?) in the guest window is, "Display output is not active." The condition happens with both VIRTIO and VGA models. Also see <https://imgur.com/a/tEp73k2>;. I have not found a workaround to stop it from happening or recover after it happens. I have to Force Off the VM and then restart the VM to the display back. My host power configuration is: disable sleep, suspend, hibernate and hybrid-sleep via systemd's systemctl. However, I allow the monitor to be turned off after 15 minutes of inactivity. My guest power configuration is whatever the distro provides. Based on my searching, others have experienced the problem. And one fellow says switching to the VGA model fixed it for him. (But no joy for me).

Does anyone have any suggestions for a work around? Thanks in advance. (And my apologies if this is the wrong list).

On Mon, Jun 23, 2025 at 05:31:46AM -0400, Jeffrey Walton wrote: >On Fri, Jun 20, 2025 at 7:35 PM Jeffrey Walton <noloader(a)gmail.com&gt; wrote: >> >> I'm working on Ubuntu 22.04.5, amd64, fully patched. It provides QEMU >> 1:6.2+dfsg-2ubuntu6.26 and libvirt 8.0.0-1ubuntu7.11. >> >> The problem I am experiencing is, when the host machine blanks the >> monitor, I lose the display on the guest when I sit back down at the >> computer and wake the monitor. The error message (?) in the guest >> window is, "Display output is not active." The condition happens with >> both VIRTIO and VGA models. Also see <https://imgur.com/a/tEp73k2>;. >> >> I have not found a workaround to stop it from happening or recover >> after it happens. I have to Force Off the VM and then restart the VM >> to the display back. >> >> My host power configuration is: disable sleep, suspend, hibernate and >> hybrid-sleep via systemd's systemctl. However, I allow the monitor to >> be turned off after 15 minutes of inactivity. My guest power >> configuration is whatever the distro provides. >> >> Based on my searching, others have experienced the problem. And one >> fellow says switching to the VGA model fixed it for him. (But no joy >> for me). When this happens to me, I literally just move the mouse, press a key, basically just send some HW input to the guest. The only time that did not work was when the resolution was automatically changed to something not working. But that was with virt-viewer/virt-manager.

>Here is the post where the person says VGA fixed it for him: ><https://www.tarball.ca/posts/cockpit-kvm-display-output-is-not-active/>. >But again, no joy for me. > What sticks out in the link above is that it is in cockpit. Could it be cockpit's fault? Can you try reproducing it without cockpit, with just virt-viewer for example?