[Pkg-libvirt-maintainers] Bug#1144573: remote-viewer: cursor gets trapped (certain SPICE clients)

[Samuel Plavec]

Package: virt-viewer
Version: 11.0-3+b1
Severity: normal

Dear Maintainer,

When a QEMU guest without spice-vdagent runs on a VM with virtio-vga,
the guest doesn't receive mouse input. (Tested on Debian Sid as the
guest.) This behavior confuses remote-viewer connected to it through
SPICE; when the cursor enters a focused remote-viewer window (i.e.
the window is the top window), the cursor disappears, and it doesn't
reappear even after mouse movement.

To make the cursor usable again, pressing Shift+F12 does *not* suffice.
(However, in some cases, it may be necessary to press Shift+F12 before
carrying out the following step.) To ungrab the cursor, one needs to
unfocus the remote-viewer window. (This can usually be done by pressing
the Windows key.)

However, this issue does not manifest when the guest runs spice-vdagent;
in that case, the cursor can be moved and can exit the window.

Nor does this issue happen when remote-viewer is connected to a VM with
QXL graphics; the host cursor disappears when it enters the remote-viewer
window, but it can exit the window. Interestingly, VMs with QXL can
receive mouse input even without running spice-vdagent, unlike VMs
with virtio-vga.

Host system information generated by reportbug is attached. I experience
this bug on KDE Plasma on Wayland.

Best Regards,
Samuel Plavec
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-- System Information:
Debian Release: 13.6
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 6.12.101+deb13-amd64 (SMP w/2 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages virt-viewer depends on:
ii  libc6                       2.41-12+deb13u3
ii  libgdk-pixbuf-2.0-0         2.42.12+dfsg-4+deb13u1
ii  libglib2.0-0t64             2.84.4-3~deb13u3
ii  libgtk-3-0t64               3.24.49-3
ii  libgtk-vnc-2.0-0            1.5.0-1
ii  libgvnc-1.0-0               1.5.0-1
ii  libpango-1.0-0              1.56.3-1
ii  libspice-client-glib-2.0-8  0.42-3
ii  libspice-client-gtk-3.0-5   0.42-3
ii  libvirt-glib-1.0-0          5.0.0-2+b4
ii  libvirt0                    11.3.0-3+deb13u2
ii  libvte-2.91-0               0.80.1-1
ii  libxml2                     2.12.7+dfsg+really2.9.14-2.1+deb13u3

virt-viewer recommends no packages.

Versions of packages virt-viewer suggests:
ii  netcat-openbsd [netcat]      1.229-1
ii  netcat-traditional [netcat]  1.10-50

-- no debconf information