How to recover from "Display output is not active"
Hi Everyone, 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). Jeff
On Fri, Jun 20, 2025 at 7:35 PM Jeffrey Walton <noloader@gmail.com> 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).
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.
Does anyone have any suggestions for a work around?
Thanks in advance. (And my apologies if this is the wrong list).
Jeff
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@gmail.com> 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?
Does anyone have any suggestions for a work around?
Thanks in advance. (And my apologies if this is the wrong list).
Jeff
On Tue, Jun 24, 2025 at 9:10 AM Martin Kletzander <mkletzan@redhat.com> wrote:
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@gmail.com> 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.
Yeah, that does not work for me.
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?
My bad, I am using virt-manager. I'd like to try to tweak the BIOS on the VM, but I don't see it listed in virt-manager for the VM. How do I get to the BIOS settings? (On real hardware, I usually disable S3/S45/S5 sleep states in the BIOS or UEFI, and let Systemd handle power management). Jeff
On Sun, Jul 06, 2025 at 02:18:47PM -0400, Jeffrey Walton wrote:
On Tue, Jun 24, 2025 at 9:10 AM Martin Kletzander <mkletzan@redhat.com> wrote:
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@gmail.com> 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.
Yeah, that does not work for me.
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?
My bad, I am using virt-manager.
I'd like to try to tweak the BIOS on the VM, but I don't see it listed in virt-manager for the VM. How do I get to the BIOS settings?
(On real hardware, I usually disable S3/S45/S5 sleep states in the BIOS or UEFI, and let Systemd handle power management).
If you are connected to the display early enough you can press some key (based on whether it is using UEFI or BIOS) to get to the settings. Depends what you want to tweak there, some things can be tweaked in the XML as well (boot order etc.) and you can also set `<bios useserial='yes'/>` to get the bios on serial console (with `virsh console` or `virsh start --console` for example). If you only want to disable sleep then it is done by default on virt-manager created VMs I believe, or you can do it with: https://libvirt.org/formatdomain.html#power-management but IIRC it only works with BIOS, not UEFI.
Jeff
On Fri, Jun 20, 2025 at 7:35 PM Jeffrey Walton <noloader@gmail.com> wrote:
Hi Everyone,
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
Ugh, an important data point... The two machines experiencing "Display output is not active" are KDE Plasma machines. I just learned that a Debian/LXDE virtual machine does not have the problem. On the LXDE machine, the display goes inactive, but it comes back to life (wakes? activates?) when the mouse is moved. So it looks like a KDE specific issue. Jeff
participants (2)
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Jeffrey Walton -
Martin Kletzander