Dear Maintainer,
plasma-systemmonitor is poorly usable due to graphical artefacts with
nouveau kernel module
* What led up to the situation?
The issue appeared after a successful dist-upgrade from Debian
Bullseye (11.7) to Debian Bookworm (12.0) on a computer running KDE on
Xorg with an nvidia graphic card (GeForce 9600M GT) driven by the
nouveau kernel module:
$ inxi -G
Graphics:
Device-1: NVIDIA G96CM [GeForce 9600M GT] driver: nouveau v: kernel
Display: x11 server: X.Org v: 1.21.1.7 with: Xwayland v: 22.1.9
driver: X:
loaded: modesetting unloaded: fbdev,vesa dri: nouveau gpu: nouveau
resolution: 1280x800~60Hz
API: OpenGL v: 3.3 Mesa 22.3.6 renderer: NV96
The KDE "about" information is:
Operating System: Debian GNU/Linux 12
KDE Plasma Version: 5.27.5
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8
Kernel Version: 6.1.0-9-amd64 (64-bit)
Graphics Platform: X11
Processors: 2 × Intel® Core™2 Duo CPU P8400 @ 2.26GHz
Memory: 2.9 GiB of RAM
Graphics Processor: NV96
Manufacturer: Acer
Product Name: Aspire 5930
System Version: 0100
* What exactly did you do (or not do) that was effective (or
ineffective)?
I did a complete dist-upgrade according to Debian Bookworm release notes.
* What was the outcome of this action?
KDE's plasma-systemmonitor (KDE's system monitor) shows graphical
artefacts and this makes the application poorly usable. The artefacts
are more more visible when the mouse hovers on a list of items (for
example, the list of running processes or a list of items in the
program's menu (two screen shots attached).
The nouveau kernel module continuously reports the following same error
messages (in kernel's log) as long as plasma-systemmonitor is running:
lug 03 09:20:39 debian kernel: nouveau 0000:01:00.0: gr: TRAP_MP -
TP0:00000010 [LOCAL_LIMIT_WRITE]
lug 03 09:20:39 debian kernel: nouveau 0000:01:00.0: gr: TRAP_MP -
TP1:00000010 [LOCAL_LIMIT_WRITE]
lug 03 09:20:39 debian kernel: nouveau 0000:01:00.0: gr: TRAP_PROP - TP
0 - Unknown CUDA fault at address 00201a3800
lug 03 09:20:39 debian kernel: nouveau 0000:01:00.0: gr: TRAP_PROP - TP
0 - e0c: 00000000, e18: 00000f02, e1c: 00000000, e20: 00000000, e24:
09030000
lug 03 09:20:39 debian kernel: nouveau 0000:01:00.0: gr: TRAP_PROP - TP
1 - Unknown CUDA fault at address 00201a9100
lug 03 09:20:39 debian kernel: nouveau 0000:01:00.0: gr: TRAP_PROP - TP
1 - e0c: 00000000, e18: 00000ff2, e1c: 00000000, e20: 00000000, e24:
09030000
lug 03 09:20:39 debian kernel: nouveau 0000:01:00.0: gr: 00200000 [] ch
16 [001e4c6000 Xorg[787]] subc 3 class 8297 mthd 15e0 data 00000000
lug 03 09:20:39 debian kernel: nouveau 0000:01:00.0: fb: trapped write
at 00201a3800 on channel 16 [1e4c6000 Xorg[787]] engine 00 [PGRAPH]
client 0b [PROP] subclient 09 [LOCAL] reason 00000002 [PAGE_NOT_PRESENT]
The overall graphical performance of the system during the issue is
affected when plasma-systemmonitor is running, too.
When plasma-systemmonitor is stopped, the graphical performance returns
normal and the nouveau kernel module stops generating error messages in
kernel's log.
It seems that plasma-systemmonitor is triggering a malfunction in the
graphical stack (detected by nouveau kernel module) and the graphic
artefacts are a consequence of it.
The plasma-systemmonitor distributed with Debian Bookworm uses Qt5 QML
[1]. QML should make use of GPU acceleration, unlike in the system
monitor distributed with previous versions of KDE. Some reports have
previously shown similar issues [2].
The issue disappears if run plasma-systemmonitor runs from command line
disabling the hardware acceleration by Mesa 3D [3] with the following
command that forces software rendering:
$ LIBGL_ALWAYS_SOFTWARE=1 plasma-systemmonitor
* What outcome did you expect instead?
I would expect plasma-systemmonitor to be running out of the box
(with graphical acceleration from nouveau kernel module) without
graphical artefacts.
---
[1] [https://stackoverflow.com/questions/39081028/qml-garbled-text-with-
colorful-pixels-around-it-on-intel-gpu
[2] https://github.com/albertlauncher/albert/issues/516
[3] https://docs.mesa3d.org/envvars.html