Public bug reported:
**Description of the Issue:**
On Ubuntu 25.10 installed on a 2009 iMac (Model A1225, EMC 2134), I'm
experiencing progressive graphics rendering glitches in the GNOME Wayland
session. The issues start after a period of normal use (e.g., 30-60 minutes)
and include:
- Fonts in window titles rendering incorrectly (malformed or garbled
characters).
- Icons disappearing or displaying oddly (e.g., distorted or blank).
- Escalation: Half of the desktop wallpaper disappearing (e.g., only top or
bottom visible).
- Further escalation: Firefox browser tab titles going missing (tabs themselves
functional, but text vanishes).
The glitches accumulate over time but are fully resolved by logging out
and back in (no reboot needed). No full crashes or freezes occur—just
visual corruption. Non-GNOME apps like Firefox are affected via
XWayland.
**Hardware Details:**
- iMac Model: A1225 (EMC 2134), approximately 2009 era (though some sources
list as Early 2008).
- Graphics: NVIDIA MCP79/MCP7A (reported as NVAC in glxinfo).
- Upgrades: 6GB RAM, 2TB SSD.
- Driver: Nouveau (open-source, via Mesa). Proprietary NVIDIA drivers are not
supported on this ancient hardware.
**Software Details:**
- OS: Ubuntu 25.10 (fresh install).
- Session: Wayland (confirmed via `echo $XDG_SESSION_TYPE` outputting
"wayland").
- DE: Default GNOME (version 49 in 25.10).
- Kernel: Default 6.11 (or whichever is current—haven't tested older kernels
yet).
**Reproduction Steps:**
1. Boot into default Ubuntu (GNOME on Wayland) session.
2. Use the system normally (e.g., open Settings, Files, Firefox; browse, type,
etc.).
3. After 30-60 minutes (variable), observe initial glitches in window titles
and icons.
4. Continue use: Wallpaper partially vanishes, then Firefox tab titles
disappear.
5. Log out and back in: All issues resolved temporarily.
**Diagnostic Outputs:**
- `dmesg | grep nouveau` (shows normal driver loading with benign channel init
failures from GStreamer probes):
[ 17.315564] nouveau 0000:03:00.0: enabling device (0002 -> 0003)
[ 17.315870] nouveau 0000:03:00.0: NVIDIA MCP79/MCP7A (0ac380b1)
[ 17.372763] nouveau 0000:03:00.0: bios: version 62.79.50.00.08
[ 17.459057] nouveau 0000:03:00.0: vgaarb: deactivate vga console
[ 17.505541] nouveau 0000:03:00.0: fb: 256 MiB stolen system memory
[ 17.896644] nouveau 0000:03:00.0: drm: VRAM: 256 MiB
[ 17.896652] nouveau 0000:03:00.0: drm: GART: 1048576 MiB
[ 17.896656] nouveau 0000:03:00.0: drm: TMDS table version 2.0
[ 17.900694] nouveau 0000:03:00.0: drm: MM: using M2MF for buffer copies
[ 18.018052] nouveau 0000:03:00.0: [drm] Registered 2 planes with drm panic
[ 18.018056] [drm] Initialized nouveau 1.4.0 for 0000:03:00.0 on minor 1
[ 18.052165] fbcon: nouveaudrmfb (fb0) is primary device
[ 18.052176] nouveau 0000:03:00.0: [drm] fb0: nouveaudrmfb frame buffer device
[ 40.615643] nouveau 0000:03:00.0: gst-plugin-scan[2216]: channel failed to
initialise, -17
[ 40.617480] nouveau 0000:03:00.0: gst-plugin-scan[2340]: channel failed to
initialise, -17
[ 56.094922] nouveau 0000:03:00.0: gst-plugin-scan[3160]: channel failed to
initialise, -17
[ 56.192639] nouveau 0000:03:00.0: gst-plugin-scan[2818]: channel failed to
initialise, -17
[ 111.809872] nouveau 0000:03:00.0: ptyxis[4588]: channel failed to initialise,
-17
(Note: Error -17 is EEXIST, benign for legacy hardware—apps fall back to
software rendering.)
- `glxinfo | grep OpenGL` (confirms hardware acceleration via Mesa/Nouveau):
OpenGL vendor string: Mesa
OpenGL renderer string: NVAC
OpenGL core profile version string: 3.3 (Core Profile) Mesa 25.2.3-1ubuntu1
OpenGL core profile shading language version string: 3.30
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 3.3 (Compatibility Profile) Mesa 25.2.3-1ubuntu1
OpenGL shading language version string: 3.30
OpenGL context flags: (none)
OpenGL profile mask: compatibility profile
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.0 Mesa 25.2.3-1ubuntu1
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.00
OpenGL ES profile extensions:
**Workarounds Tested:**
- Switching to Xfce desktop environment (via `sudo apt install xfce4
xfce4-goodies`): Runs on Xorg and eliminates the glitches. This is my current
stable setup.
- GNOME on Xorg: Not available in Ubuntu 25.10 (removed in GNOME 49).
**Related Bugs/Context:**
This seems similar to other 25.10 reports of UI corruption (gray blocks over
text, flashing artifacts, missing elements) in GNOME/Wayland, often tied to
GTK4 or Mutter regressions. However, no exact match for legacy NVIDIA Nouveau +
escalating wallpaper/Firefox symptoms. Filing this to help iron out before
26.04 LTS.
**Next Steps:**
I'll attach full logs soon via `ubuntu-bug mutter` run from the affected
Wayland session.
** Affects: mutter (Ubuntu)
Importance: Undecided
Status: New
** Tags: gnome nouveau nvidia rendering-corruption ubuntu-25.10 wayland
** Tags added: way
** Tags removed: way
** Tags added: wayland
** Tags added: nouveau
** Tags added: gnome nvidia rendering-corruption ubuntu-25.10
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2138586
Title:
Progressive Wayland rendering corruption (titles, icons, wallpaper,
Firefox tabs) on legacy NVIDIA Nouveau in 25.10
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/2138586/+subscriptions
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
