Created attachment 12124 [details]
Blacked-out panels, but mouse finds information in right locations

Hi ,thanks reporting this.

This is a renderer error which could come from either KWin_x11 or drivers.
Could you give us the output of the command

$ inxi -FAG

And attach here the results? If inxi is not installed, please do # urpmi inxi


Also, in systemsettings5 (KDE Plasma System Config), in Displays, Compositor, select the renderer to XRender in meantime to see difference.

CC: (none) => ouaurelien

# inxi -FAG
System:
  Host: genesis Kernel: 5.10.1-desktop-2.mga8 i686 bits: 32 
  Desktop: KDE Plasma 5.20.4 Distro: Mageia 8 mga8 
Machine:
  Type: Desktop System: Dell product: Precision WorkStation 390 v: N/A 
  serial: C8BFXB1 
  Mobo: Dell model: 0GH911 serial: ..CN7082167OH0R0. BIOS: Dell v: 2.6.0 
  date: 05/19/2008 
CPU:
  Info: Dual Core model: Intel Core2 6700 bits: 64 type: MCP 
  L2 cache: 4 MiB 
  Speed: 1596 MHz min/max: 1600/2667 MHz Core speeds (MHz): 1: 1596 
  2: 1596 
Graphics:
  Device-1: NVIDIA NV42GL [Quadro FX 3450/4000 SDI] driver: N/A 
  Display: x11 server: Mageia X.org 1.20.10 driver: v4l,vesa 
  resolution: 1024x768 
  OpenGL: renderer: llvmpipe (LLVM 11.0.1 128 bits) v: 4.5 Mesa 20.3.1 
Audio:
  Device-1: Intel NM10/ICH7 Family High Definition Audio 
  driver: snd_hda_intel 
  Sound Server: ALSA v: k5.10.1-desktop-2.mga8 
Network:
  Device-1: Broadcom NetXtreme BCM5754 Gigabit Ethernet PCI Express 
  driver: tg3 
  IF: enp4s0 state: up speed: 100 Mbps duplex: full 
  mac: 00:13:72:2d:04:cc 
Drives:
  Local Storage: total: 111.79 GiB used: 10.79 GiB (9.6%) 
  ID-1: /dev/sda vendor: SanDisk model: SDSSDA120G size: 111.79 GiB 
Partition:
  ID-1: / size: 14.89 GiB used: 8.45 GiB (56.7%) fs: ext4 dev: /dev/sda1 
  ID-2: /home size: 79 GiB used: 2.31 GiB (2.9%) fs: reiserfs 
  dev: /dev/sda7 
  ID-3: /opt size: 9.76 GiB used: 32.1 MiB (0.3%) fs: reiserfs 
  dev: /dev/sda6 
Swap:
  ID-1: swap-1 type: partition size: 7.83 GiB used: 0 KiB (0.0%) 
  dev: /dev/sda5 
Sensors:
  System Temperatures: cpu: 47.0 C mobo: N/A 
  Fan Speeds (RPM): cpu: 1035 mobo: 1388 
Info:
  Processes: 190 Uptime: 1h 11m Memory: 3.82 GiB used: 1.55 GiB (40.6%) 
  Shell: Bash inxi: 3.2.00 
------------

It was a bit of work figuring-out where to find Compositor, but fortunately the right screen showed information after clicking the various icons in the black-area. I'll need to logout, or reboot to see what happens with Xrender now (instead of OpenGL2). rebooting now.....

Xrender shows no difference for LXDE, XFCE or Plasma, except I am guessing Xrender starts an X window (in plasma), then opens "System Settings" or Kmail inside this black area with a red bar.
There isn't much screen space to play with - For XFCE and LXDE they both respect opening the monitor as 1280x1024, but plasma seems to only like 1024x800 even if I tried using the custom setting 1280x1024 in MCC - no effect.

The black panels persist.

Running Kmail from a terminal in Plasma shows no clues:
$ kmail
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Cannot initialize model with data QJsonObject() . missing: QJsonValue(string, "urls")
Connection to speech-dispatcher failed

Running Kmail from a terminal in XFCE has references to gtk3 (did not test LXDE)
$ kmail

(kmail:2291): Gtk-WARNING **: 00:31:20.554: Theme parsing error: gtk.css:2:33: Failed to import: Error opening file /home/dad/.config/gtk-3.0/window_decorations.css: No such file or directory

(akonadi_control:2307): Gtk-WARNING **: 00:31:21.004: Theme parsing error: gtk.css:2:33: Failed to import: Error opening file /home/dad/.config/gtk-3.0/window_decorations.css: No such file or directory
org.kde.pim.akonadicontrol: Service org.freedesktop.Akonadi.Control.lock already registered, terminating now.
kf.kwidgetsaddons: Invalid pixmap specified.
kf.kwidgetsaddons: Invalid pixmap specified.
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Connection to speech-dispatcher failed
Cannot initialize model with data QJsonObject() . missing: QJsonValue(string, "urls")
kf.kwidgetsaddons: Invalid pixmap specified.
kf.kwidgetsaddons: Invalid pixmap specified.
kf.kwidgetsaddons: No frame loaded
^C


Running systemsettings5 in Plasma shows:
$ systemsettings5 
Cyclic dependency detected between "file:///usr/lib/qt5/qml/org/kde/kirigami.2/styles/org.kde.desktop.plasma/Units.qml" and "file:///usr/lib/qt5/qml/org/kde/kirigami.2/styles/org.kde.desktop.plasma/Units.qml"
file:///usr/share/kpackage/genericqml/org.kde.systemsettings.sidebar/contents/ui/SubCategoryPage.qml:142:9: QML Connections: Implicitly defined onFoo properties in Connections are deprecated. Use this syntax instead: function onFoo(<arguments>) { ... }
file:///usr/share/kpackage/genericqml/org.kde.systemsettings.sidebar/contents/ui/SubCategoryPage.qml:132:9: QML Connections: Implicitly defined onFoo properties in Connections are deprecated. Use this syntax instead: function onFoo(<arguments>) { ... }
file:///usr/lib/qt5/qml/org/kde/kirigami.2/private/RefreshableScrollView.qml:137:13: QML Connections: Implicitly defined onFoo properties in Connections are deprecated. Use this syntax instead: function onFoo(<arguments>) { ... }
file:///usr/lib/qt5/qml/org/kde/kirigami.2/private/RefreshableScrollView.qml:137:13: QML Connections: Implicitly defined onFoo properties in Connections are deprecated. Use this syntax instead: function onFoo(<arguments>) { ... }
Cyclic dependency detected between "file:///usr/lib/qt5/qml/org/kde/kirigami.2/styles/org.kde.desktop.plasma/Units.qml" and "file:///usr/lib/qt5/qml/org/kde/kirigami.2/styles/org.kde.desktop.plasma/Units.qml"
QQmlEngine::setContextForObject(): Object already has a QQmlContext
file:///usr/share/kpackage/genericqml/org.kde.systemsettings.sidebar/contents/ui/introPage.qml:109:27: QML IntroIcon (parent or ancestor of QQuickLayoutAttached): Binding loop detected for property "minimumHeight"
file:///usr/share/kpackage/genericqml/org.kde.systemsettings.sidebar/contents/ui/introPage.qml:109:27: QML IntroIcon (parent or ancestor of QQuickLayoutAttached): Binding loop detected for property "minimumHeight"


and running systemsettings5 in LXDE shows (did not try XFCE):
(systemsettings5:2543): Gtk-WARNING **: 00:28:23.764: Theme parsing error: gtk.css:2:33: Failed to import: Error opening file /home/dad/.config/gtk-3.0/window_decorations.css: No such file or directory
file:///usr/share/kpackage/genericqml/org.kde.systemsettings.sidebar/contents/ui/SubCategoryPage.qml:142:9: QML Connections: Implicitly defined onFoo properties in Connections are deprecated. Use this syntax instead: function onFoo(<arguments>) { ... }
file:///usr/share/kpackage/genericqml/org.kde.systemsettings.sidebar/contents/ui/SubCategoryPage.qml:132:9: QML Connections: Implicitly defined onFoo properties in Connections are deprecated. Use this syntax instead: function onFoo(<arguments>) { ... }
file:///usr/lib/qt5/qml/org/kde/kirigami.2/private/RefreshableScrollView.qml:137:13: QML Connections: Implicitly defined onFoo properties in Connections are deprecated. Use this syntax instead: function onFoo(<arguments>) { ... }
file:///usr/lib/qt5/qml/org/kde/kirigami.2/private/RefreshableScrollView.qml:137:13: QML Connections: Implicitly defined onFoo properties in Connections are deprecated. Use this syntax instead: function onFoo(<arguments>) { ... }
file:///usr/share/kpackage/genericqml/org.kde.systemsettings.sidebar/contents/ui/introPage.qml:109:27: QML IntroIcon (parent or ancestor of QQuickLayoutAttached): Binding loop detected for property "minimumHeight"
file:///usr/share/kpackage/genericqml/org.kde.systemsettings.sidebar/contents/ui/introPage.qml:109:27: QML IntroIcon (parent or ancestor of QQuickLayoutAttached): Binding loop detected for property "minimumHeight"


Also another thing....the icons in the left panel seem scrunched much closer together vertically even though I can't see them, no help-pop-ups seem to show after about mid-panel downwards - the last pop-up seems to be activities

Created attachment 12125 [details]
System-Settings with Xrender turned-on - left panel icons stop about midway

Found similar bug in kde for kmail - did not search for systemsettings5 but suspect it is similar problem too.
https://bugs.kde.org/show_bug.cgi?id=397825

(In reply to Joe Da Silva from comment #6)
> Found similar bug in kde for kmail - did not search for systemsettings5 but
> suspect it is similar problem too.
> https://bugs.kde.org/show_bug.cgi?id=397825

This is unrelated, as it refers to a wayland session.

According to your inxi output:
Device-1: NVIDIA NV42GL [Quadro FX 3450/4000 SDI] driver: N/A 
  Display: x11 server: Mageia X.org 1.20.10 driver: v4l,vesa 
  resolution: 1024x768 
  OpenGL: renderer: llvmpipe (LLVM 11.0.1 128 bits) v: 4.5 Mesa 20.3.1 

You are using totally wrong driver for this card and the X server use bad rendering on this card.
NVIDIA NV42GL / Quadro FX 3450/4000 should use the 304.137 nonfree drivers on this card.

Use XFDrake, it should tell you the correct nonfree driver.

Thanks Aurélien for this detail.
@Joe : can you please reply to the previous comment?

Hi Aurelien, Hi Lewis,
Just updated to the latest patches and updates (as per now/today), plus I modified/let Mageia8beta1 to choose the default (not the same description as per Mageia6 - display driver).

now "inxi -FAG"
Graphics:
  Device-1: NVIDIA NV42GL [Quadro FX 3450/4000 SDI] driver: nouveau 
  v: kernel 
  Display: x11 server: Mageia X.org 1.20.10 driver: nouveau,v4l resolution: 
  1: 1280x1024~60Hz 2: 1280x1024~60Hz 
  OpenGL: renderer: NV42 v: 2.1 Mesa 20.3.1 

I was expecting nouveau to be a disappointment, but it bahaves better than expected. Plasma/Wayland still continues to render triangles and freezes.

...however, LXDE and XFCE appear to work fine for the brief time tested.
All three instances are like Aurelien indicates - (avoid the Xorg-VESA, and I also tried Generic VESA too).

We can probably close this bug - I'll attach images (reduced file sizes).

Created attachment 12153 [details]
Plasma Wayland choppy triangles (but KMAIL window renders okay).

Created attachment 12154 [details]
XFCE Kmail renders okay with XFCE (and LXDE) - image is reduced file size

black preview window renders okay with nouveau driver

Caould this be related to Bug 27945 ?

CC: (none) => lewyssmith

Hi Lewis, It appears co-incidental. 0,0,0 would be black, and then there is also the transparency/opaque layer which could be a flag setting.

In any case, I attempted to revert back to Xorg-vesa to see if I could replicate the problem to see if I could test that too. However, seems recent updates have fixed the problem I had. Looks fixed now using the default graphics driver as well as the Xorg-vesa driver I was referred to earlier (back with Mageia7).

Since It appears fixed - I think this particular bug can be closed.
One or more of the many Mageia8 patches fixed my problem - it may have been going from QT5.15.1 towards QT5.15.2 and reviewing another user here https://bugs.kde.org/show_bug.cgi?id=397825 it may have been somewhere from 1->2
...but I'm only guessing.
Aurelien was also right in changing from Xorg-vesa to default Nvidia nouveu driver was a solution too.

I will attach the LXDE systemsettings5 screenshot now (which showed-up as all black earlier) - it looks much better now, but contains a quirk in the left panel.

Let me know if you want this bug as a new bug - as it appears to be only LXDE related.

Created attachment 12160 [details]
LXDE left-panel view of systemsettings (graphics blocks)

Thank you for all your toil on this.
> Since It appears fixed - I think this particular bug can be closed.
I think it would help to close this bug, and open another for the last point about the KDE/Plasma System Settings panel deformation with LXDE - if it actually matters (who would use it outside Plasma?). It needs other non-Plasma desktops with similar nVidia H/W to persue it.

Use the same attachment, and for related graphical info (it all became a bit confused):
 $ inxi -G++ -S

Resolution: (none) => FIXED
Status: NEW => RESOLVED