I've been trying to reproduce this issue on an Ubuntu 24.04 host, by booting into a Xubuntu 25.10 live system and changing the resolution via StartMenu->Settings->Display.
$ wget https://cdimage.ubuntu.com/xubuntu/releases/questing/release/xubuntu-25.10-desktop-amd64.iso $ qemu-system-x86_64 -enable-kvm -m 2G -nic user,model=virtio-net-pci -cdrom xubuntu-25.10-desktop-amd64.iso => When launching the ISO via this simple qemu command above, everything works as expected. But when launching via virt-manager's default settings, I see the same behavior as described by Heinrich in comment #6: The screen resolution changes, but the mouse-pointer has a certain offset in x+y directions, so we cannot click any buttons and the screen can make the impression of being frozen. It isn't really frozen, though, as we can still navigate using the keyboard. The qemu command line used by my virt-manager looks like this (similar to comment #8): $ ps faux | grep qemu libvirt+ 320897 37.6 17.6 5499536 4301780 ? Sl 11:06 2:27 /usr/bin/qemu-system-x86_64 -name guest=xubuntu25.10,debug-threads=on -S -object {"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain-4-xubuntu25.10/master-key.aes"} -machine pc-q35-8.2,usb=off,vmport=off,dump-guest-core=off,memory-backend=pc.ram,hpet=off,acpi=on -accel kvm -cpu host,migratable=on -m size=4194304k -object {"qom-type":"memory-backend-ram","id":"pc.ram","size":4294967296} -overcommit mem-lock=off -smp 2,sockets=2,cores=1,threads=1 -uuid 6cb399e0-683c-4319-bc42-bbc3e3d345d2 -no-user-config -nodefaults -chardev socket,id=charmonitor,fd=33,server=on,wait=off -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=delay -no-shutdown -global ICH9-LPC.disable_s3=1 -global ICH9-LPC.disable_s4=1 -boot strict=on -device {"driver":"pcie-root-port","port":16,"chassis":1,"id":"pci.1","bus":"pcie.0","multifunction":true,"addr":"0x2"} -device {"driver":"pcie-root-port","port":17,"chassis":2,"id":"pci.2","bus":"pcie.0","addr":"0x2.0x1"} -device {"driver":"pcie-root-port","port":18,"chassis":3,"id":"pci.3","bus":"pcie.0","addr":"0x2.0x2"} -device {"driver":"pcie-root-port","port":19,"chassis":4,"id":"pci.4","bus":"pcie.0","addr":"0x2.0x3"} -device {"driver":"pcie-root-port","port":20,"chassis":5,"id":"pci.5","bus":"pcie.0","addr":"0x2.0x4"} -device {"driver":"pcie-root-port","port":21,"chassis":6,"id":"pci.6","bus":"pcie.0","addr":"0x2.0x5"} -device {"driver":"pcie-root-port","port":22,"chassis":7,"id":"pci.7","bus":"pcie.0","addr":"0x2.0x6"} -device {"driver":"pcie-root-port","port":23,"chassis":8,"id":"pci.8","bus":"pcie.0","addr":"0x2.0x7"} -device {"driver":"pcie-root-port","port":24,"chassis":9,"id":"pci.9","bus":"pcie.0","multifunction":true,"addr":"0x3"} -device {"driver":"pcie-root-port","port":25,"chassis":10,"id":"pci.10","bus":"pcie.0","addr":"0x3.0x1"} -device {"driver":"pcie-root-port","port":26,"chassis":11,"id":"pci.11","bus":"pcie.0","addr":"0x3.0x2"} -device {"driver":"pcie-root-port","port":27,"chassis":12,"id":"pci.12","bus":"pcie.0","addr":"0x3.0x3"} -device {"driver":"pcie-root-port","port":28,"chassis":13,"id":"pci.13","bus":"pcie.0","addr":"0x3.0x4"} -device {"driver":"pcie-root-port","port":29,"chassis":14,"id":"pci.14","bus":"pcie.0","addr":"0x3.0x5"} -device {"driver":"qemu-xhci","p2":15,"p3":15,"id":"usb","bus":"pci.2","addr":"0x0"} -device {"driver":"virtio-serial-pci","id":"virtio-serial0","bus":"pci.3","addr":"0x0"} -blockdev {"driver":"file","filename":"/var/lib/libvirt/images/xubuntu25.10.qcow2","node-name":"libvirt-2-storage","auto-read-only":true,"discard":"unmap"} -blockdev {"node-name":"libvirt-2-format","read-only":false,"discard":"unmap","driver":"qcow2","file":"libvirt-2-storage","backing":null} -device {"driver":"virtio-blk-pci","bus":"pci.4","addr":"0x0","drive":"libvirt-2-format","id":"virtio-disk0","bootindex":2} -blockdev {"driver":"file","filename":"/media/Daten/xubuntu-25.10-desktop-amd64.iso","node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"} -blockdev {"node-name":"libvirt-1-format","read-only":true,"driver":"raw","file":"libvirt-1-storage"} -device {"driver":"ide-cd","bus":"ide.0","drive":"libvirt-1-format","id":"sata0-0-0","bootindex":1} -netdev {"type":"tap","fd":"34","vhost":true,"vhostfd":"36","id":"hostnet0"} -device {"driver":"virtio-net-pci","netdev":"hostnet0","id":"net0","mac":"52:54:00:32:c1:82","bus":"pci.1","addr":"0x0"} -chardev pty,id=charserial0 -device {"driver":"isa-serial","chardev":"charserial0","id":"serial0","index":0} -chardev socket,id=charchannel0,fd=32,server=on,wait=off -device {"driver":"virtserialport","bus":"virtio-serial0.0","nr":1,"chardev":"charchannel0","id":"channel0","name":"org.qemu.guest_agent.0"} -chardev spicevmc,id=charchannel1,name=vdagent -device {"driver":"virtserialport","bus":"virtio-serial0.0","nr":2,"chardev":"charchannel1","id":"channel1","name":"com.redhat.spice.0"} -device {"driver":"usb-tablet","id":"input0","bus":"usb.0","port":"1"} -audiodev {"id":"audio1","driver":"spice"} -spice port=5900,addr=127.0.0.1,disable-ticketing=on,image-compression=off,seamless-migration=on -device {"driver":"virtio-vga","id":"video0","max_outputs":1,"bus":"pcie.0","addr":"0x1"} -device {"driver":"ich9-intel-hda","id":"sound0","bus":"pcie.0","addr":"0x1b"} -device {"driver":"hda-duplex","id":"sound0-codec0","bus":"sound0.0","cad":0,"audiodev":"audio1"} -global ICH9-LPC.noreboot=off -watchdog-action reset -chardev spicevmc,id=charredir0,name=usbredir -device {"driver":"usb-redir","chardev":"charredir0","id":"redir0","bus":"usb.0","port":"2"} -chardev spicevmc,id=charredir1,name=usbredir -device {"driver":"usb-redir","chardev":"charredir1","id":"redir1","bus":"usb.0","port":"3"} -device {"driver":"virtio-balloon-pci","id":"balloon0","bus":"pci.5","addr":"0x0"} -object {"qom-type":"rng-random","id":"objrng0","filename":"/dev/urandom"} -device {"driver":"virtio-rng-pci","rng":"objrng0","id":"rng0","bus":"pci.6","addr":"0x0"} -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on So now we need to figure out which command line argument breaks the screen-resize functionality in Xubuntu, by adding them one-by-one to the known good "simple" command from above. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2126798 Title: Can not change screen resolution in Xubuntu-25.10-beta running in KVM/QEMU To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/2126798/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
