Intense drawing artifacts on GNOME Wayland in vncviewer

[eomanis]

Describe the bug
The FLTK VNC viewer is unusable because drawing is glitching intensely.

Basically, on every surface update the picture gets brighter and brighter, until almost everything is white.
See attached video.

The following behaviors can be observed:

• Entering the GNOME Shell's overview mode partly resets the drawing
• The Java VNC viewer is not affected, and neither is Remmina
• Another FLTK application, in this case the dillo web browser in version 3.0.5, is not affected
• Screenshots with the GNOME Shell built-in screenshot functionality yield pictures where the drawing surface of the VNC viewer window is transparency
• In screen recordings with the GNOME Shell built-in screenshot functionality the VNC viewer window looks as it should, i.e. does not show the glitchy drawing; same goes for the preview in OBS when capturing the respective screen with Pipewire

To Reproduce
Steps to reproduce the behavior:

1. Open the native (FLTK) VNC viewer in a GNOME Wayland session
2. Connect to a VNC server
3. Note the drawing artifacts described above

Expected behavior
The view of the VNC server's desktop should be painted without glitches.

Screenshots
Smartphone video recording showing the drawing glitches; the VNC server is showing a website in fullscreen mode in Firefox:
https://github.com/TigerVNC/tigervnc/assets/5933155/e6bc077a-d172-4a5c-ba26-9e66ef511cc4

Client (please complete the following information):

• OS: Arch Linux
• VNC client: TigerVNC, /usr/bin/vncviewer
• VNC client version: 1.13.1-2
• Client downloaded from: Arch Linux packages mirror, with the distribution's package manager pacman

Server (please complete the following information):

• OS: Arch Linux
• VNC server: TigerVNC, /usr/bin/x0vncserver
• VNC server version: 1.13.1-2
• Server downloaded from: Arch Linux packages mirror, with the distribution's package manager pacman
• Server was started using: /usr/bin/x0vncserver -PasswordFile /home/theuser/.vnc/passwd -display :0

Additional context

• The other tested FLTK application dillo that does not show the glitch was built 2022-11-01, whereas the affected TigerVNC package was built 2023-08-10. Maybe this is a FLTK regression that happened between these builds.
• GNOME Shell version 44.4 (gnome-shell-1:44.4-1)
• Mesa 23.1.6 (mesa-1:23.1.6-4)
• Graphics: AMD Radeon RX 480
• Linux 6.4.12 (linux-6.4.12.arch1-1)

[vowstar]

I also encountered the same problem，

Screenshots

Client (please complete the following information):

OS: Gentoo Linux x86_64
VNC client: TigerVNC, /usr/bin/vncviewer
VNC client version: 1.13.1
Client downloaded from: https://github.com/TigerVNC/tigervnc/archive/v1.13.1.tar.gz (and built by gentoo's ebuild from source)

Server (please complete the following information):

OS: Gentoo Linux x86_64
VNC server: TigerVNC, /usr/bin/x0vncserver, via systemd
VNC server version: 1.13.1
Server downloaded from: https://github.com/TigerVNC/tigervnc/archive/v1.13.1.tar.gz (and built by gentoo's ebuild from source)
Server was started using: systemctl start vncserver@:1.service

Additional context

GNOME Shell version 44.3
Mesa 23.2.0
Graphics: NVIDIA GeForce RTX 2080 Ti Rev. A
Linux 6.4.13-gentoo-x86_64

[samhed]

Works well for me. I cannot reproduce on Fedora 38:

Screenshots

Client:

OS: Fedora 38
VNC client: TigerVNC, /usr/bin/vncviewer
VNC client version: 1.13.1
Client downloaded from: Fedora System repository

Server:

OS: RHEL 9
VNC server: TigerVNC, /usr/bin/x0vncserver
VNC server version: 1.13.1
Server downloaded from: https://sourceforge.net/projects/tigervnc/files/stable/1.13.1/
Server was started using: /usr/bin/x0vncserver -SecurityTypes None

Additional context

GNOME Shell version 44.3
Mesa 23.1.6
Graphics: Intel Corporation CoffeeLake-S GT2 [UHD Graphics 630]
Linux 6.4.11-200.fc38.x86_64

[samhed]

I also cannot reproduce with a vncviewer downloaded from our sourceforge or with a TigerVNC vncviewer I built myself on Fedora.

[eomanis]

@vowstar Your glitches look kind of different than the ones I get, also you could capture yours in a screenshot whereas I had to use external recording.

This, along with greater differences in the graphics subsystems, makes me suspect that there are two separate graphical problems, and this one may an Arch-specific issue since it is not reproducible on @samhed 's Fedora+Wayland(?)+Mesa+Intel. Or it could be specific to AMD graphics.

Anyone have Arch+Wayland+Mesa+AMD?
Or [OtherDistro]+Wayland+Mesa+AMD?

Anyway, I'll file an issue at the Arch bug tracker.

[paquiteau]

Hello there,
I am having the same issue.

I am running a Arch + Wayland(GNOME) + Mesa (1:23.1.6-4, updated on 2023-08-31)
Hardware: Thinkpad T14 (Gen1), with AMD Ryzen 5 PRO 4650U with integrated Radeon Graphics.

When switching to use Vinagre (GNOME VNC Viewer) there is no such graphics artifacts.

On a another laptop running Ubuntu 22.04 Wayland (GNOME) with AMD Radeon Graphics, everything works fine with TigerVNC

[samhed]

So far, evidence seem to point towards Arch being the common denominator for the issue. From a comment on the arch issue tracker:

graphical glitches like this are often mesa/driver/kernel related

With this in mind, I will go ahead and close this issue for now. We will reopen if needed.

[eomanis]

Works for me again with Arch package xorg-xwayland-23.2.1-1.
May have been this issue.

[vowstar]

Works for me again with Arch package xorg-xwayland-23.2.1-1. May have been this issue.

Works for me with gentoo::x11-base/xwayland-23.2.1, may same issue. The patch works.