Bug#1109816: Broken character previews in Shell Overview

[asciiwolf at seznam.cz]

Hi Simon,




Here are some details:

$ lspci|grep VGA
00:01.0 VGA compatible controller: Red Hat, Inc. Virtio 1.0 GPU (rev 01)

$ glxinfo
...
Vendor: Mesa (0x1af4)
Device: virgl (Mesa Intel(R) UHD Graphics 620 (WHL GT2)) (0x1010)
Version: 25.0.7
Accelerated: yes
Video memory: 0MB
Unified memory: no
Preferred profile: core (0x1)
Max core profile version: 4.3
Max compat profile version: 4.3
Max GLES1 profile version: 1.1
Max GLES[23] profile version: 3.2
...

$ dpkg -l|grep mesa
ii  libegl-mesa0:amd64                      25.0.7-2                        
amd64        free implementation of the EGL API -- Mesa vendor library
ii  libegl1-mesa-dev:amd64                  25.0.7-2                        
amd64        free implementation of the EGL API -- development files
ii  libgl1-mesa-dri:amd64                   25.0.7-2                        
amd64        free implementation of the OpenGL API -- DRI modules
ii  libglu1-mesa:amd64                      9.0.2-1.1+b3                    
amd64        Mesa OpenGL utility library (GLU)
ii  libglx-mesa0:amd64                      25.0.7-2                        
amd64        free implementation of the OpenGL API -- GLX vendor library
ii  mesa-libgallium:amd64                   25.0.7-2                        
amd64        shared infrastructure for Mesa drivers
ii  mesa-va-drivers:amd64                   25.0.7-2                        
amd64        Mesa VA-API video acceleration drivers
ii  mesa-vdpau-drivers:amd64                25.0.7-2                        
amd64        Mesa VDPAU video acceleration drivers
ii  mesa-vulkan-drivers:amd64               25.0.7-2                        
amd64        Mesa Vulkan graphics drivers

Fully updated gnome-shell (48.3-1) and mutter (48.4-2).

It basically is just GNOME Boxes with 3D acceleration (via VirGL) enabled 
for the VM, running on a ThinkPad T590 laptop.




Regards,

Daniel



"Control: tags -1 + moreinfo 

On Thu, 24 Jul 2025 at 12:12:28 +0200, asciiwolf at seznam.cz wrote: 
>The character previews in GNOME Shell Overview mode are displayed as 
corrupted 
>and look very similar to broken textures caused by GPU memory corruption. 
See 
>the attached screenshot. 
> 
>It may be a GPU driver issue, as I am running the Debian Trixie instance in
a 
>virtual machine (KVM). 

The same Cyrillic character previews look fine for me on real hardware 
(Intel UHD Graphics 620) and in a virtual machine (virt-manager, spice, 
virtio video). Identifying what is different in your VM will require 
more information about the virtual hardware, and the GPU driver that is 
in use by gnome-shell. 

smcv 
"
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