[SOLVED] KDE Wayland 2nd screen is black+mouse cursor

Gass · 2026-06-23 13:37:13

Hi, I'm having issues configuring a dual screen setup, atm I have the main screen connected to DP-1 on discrete card RX 6700, this is all good shows the desktop fine. I also enabled the IGP of an AMD 5700D and conected a second monitor to that (DP-4) and I get a black screen with mouse cursor on that monitor.
DP-1 works and shows kde desktop fine, but this DP-4 only shows a black screen that does show the mouse cursor.

IDK how I managed to fuck it up but this config was working before, but I switched to having both connected to the discrete GPU for some time and then when I reverted to one monitor to each GPU this issue happens.

The reason to not have both monitors connected to the discrete GPU is because I get constant flickering on the 2nd monitor and sometimes CTD when gaming if I switch to the 2nd desktop which is annoying.

I tried:
- booting on LTS kernel, issue persists
- deleting ~/.config/kwinoutputconfig.json from a different TTY while not logged in (I do use plasma-login-manager though so that does get started), issue persists
- deleting ~/.cache, issue persists
- installed Cosmic desktop and it works fine, shows desktop on both screens

Can anyone point me on what to try next or what to look for?

Last edited by Gass (2026-06-23 20:03:26)

seth · 2026-06-23 15:20:14

Can you drag windows onto that monitor? Or do they disappear (but eg. the mouse cursor still indicates hovering events)?

qdbus6 org.kde.KWin /KWin supportInformation
kscreen-doctor

Gass · 2026-06-23 15:30:08

Yes I can drag windows there, obviously they disappear, the mouse cursor is visible though, some apps even start on that "black" screen, I can then select move->drag them to the monitor that shows the desktop, I think no hovering or at least I can't manage to trigger it. I can see the second monitor on kde display settings and change them, adjust position, etc...

- qdbus6 org.kde.KWin /KWin supportInformation

Version
=======
KWin version: 6.7.0
Qt Version: 6.11.1
Qt compile version: 6.11.1
XCB compile version: 1.17.0

Operation Mode: Wayland

Build Options
=============
KWIN_BUILD_DECORATIONS: yes
KWIN_BUILD_TABBOX: yes
KWIN_BUILD_ACTIVITIES: yes
HAVE_X11_XCB: yes

X11
===
Vendor: The X.Org Foundation
Vendor Release: 12401012
Protocol Version/Revision: 11/0
SHAPE: yes; Version: 0x11
RANDR: yes; Version: 0x14
Composite: yes; Version: 0x4
RENDER: yes; Version: 0xb
XFIXES: yes; Version: 0x50
SYNC: yes; Version: 0x31
RES: yes; Version: 0x12

Decoration
==========
Plugin: org.kde.breeze
Theme: Breeze
Plugin recommends border size: None
onAllDesktopsAvailable: false
alphaChannelSupported: true
closeOnDoubleClickOnMenu: false
alwaysShowExcludeFromCapture: false
decorationButtonsLeft: 0, 2, 12
decorationButtonsRight: 6, 3, 4, 5
borderSize: 0
gridUnit: 10
font: Noto Sans,10,-1,0,400,0,0,0,0,0,0,0,0,0,0,1,,0,0
smallSpacing: 2
largeSpacing: 10

LogicalOutput backend
==============
Name: DRM
Atomic Mode Setting on GPU 0: true
Atomic Mode Setting on GPU 1: true

Cursor
======
themeName: breeze_cursors
themeSize: 24

Options
=======
focusPolicy: ClickToFocus
xwaylandCrashPolicy: 1
xwaylandMaxCrashCount: 3
nextFocusPrefersMouse: false
clickRaise: true
autoRaise: false
autoRaiseInterval: 0
delayFocusInterval: 0
separateScreenFocus: true
placement: 5
activationDesktopPolicy: SwitchToOtherDesktop
focusPolicyIsReasonable: true
borderSnapZone: 10
windowSnapZone: 10
centerSnapZone: 0
snapOnlyWhenOverlapping: false
edgeBarrier: 100
cornerBarrier: 1
rollOverDesktops: false
perOutputVirtualDesktops: false
focusStealingPreventionLevel: 1
operationTitlebarDblClick: 5000
operationMaxButtonLeftClick: 5000
operationMaxButtonMiddleClick: 5013
operationMaxButtonRightClick: 5012
commandActiveTitlebar1: MouseRaise
commandActiveTitlebar2: MouseNothing
commandActiveTitlebar3: MouseOperationsMenu
commandInactiveTitlebar1: MouseActivateAndRaise
commandInactiveTitlebar2: MouseNothing
commandInactiveTitlebar3: MouseOperationsMenu
commandWindow1: MouseActivateRaiseOnReleaseAndPassClick
commandWindow2: MouseActivateAndPassClick
commandWindow3: MouseActivateAndPassClick
commandWindowWheel: MouseNothing
commandAll1: MouseUnrestrictedMove
commandAll2: MouseToggleRaiseAndLower
commandAll3: MouseUnrestrictedResize
keyCmdAllModKey: 16777250
doubleClickBorderToMaximize: true
condensedTitle: false
electricBorderMaximize: true
electricBorderTiling: true
electricBorderAllScreenCorner: true
electricBorderCornerRatio: 0.25
borderlessMaximizedWindows: false
killPingTimeout: 5000
compositingMode: 1
allowTearing: true
interactiveWindowMoveEnabled: true
pictureInPictureHomeCorner: BottomRightCorner
pictureInPictureMargin: 20
overlayVirtualKeyboardOnWindows: false

Screen Edges
============
desktopSwitching: false
desktopSwitchingMovingClients: false
cursorPushBackDistance: 1x1
actionTopLeft: 0
actionTop: 0
actionTopRight: 0
actionRight: 0
actionBottomRight: 0
actionBottom: 0
actionBottomLeft: 0
actionLeft: 0

Screens
=======
Number of Screens: 3

Screen 0:
---------
Name: DP-1
Enabled: 1
Geometry: 1920,0,2560x1440
Physical size: 698x393mm
Scale: 1
Refresh Rate: 164847
Adaptive Sync: automatic
Screen 1:
---------
Name: HDMI-A-1
Enabled: 0
Screen 2:
---------
Name: DP-4
Enabled: 1
Geometry: 0,0,1920x1080
Physical size: 598x336mm
Scale: 1
Refresh Rate: 144001
Adaptive Sync: automatic

Compositing
===========
Compositing is active
Compositing Type: OpenGL
OpenGL vendor string: AMD
OpenGL renderer string: AMD Radeon RX 6700 (radeonsi, navi22, ACO, DRM 3.64, 7.0.12-1-cachyos)
OpenGL version string: 4.6 (Core Profile) Mesa 26.1.2-arch3.1
OpenGL platform interface: EGL
OpenGL shading language version string: 4.60
Driver: Unknown
GPU class: Unknown
OpenGL version: 4.6
GLSL version: 4.60
Mesa version: 26.1.2
X server version: 1.24.1
Linux kernel version: 7.0.12
Direct rendering: Requires strict binding: no
Virtual Machine:  no
OpenGL 2 Shaders are used

Loaded Effects:
---------------
shakecursor
outputlocator
colorpicker
zoom
screenedge
blur
logout
login
sessionquit
slidingpopups
slidingnotifications
windowaperture
slide
maximize
fadingpopups
fullscreen
frozenapp
scale
dimscreen
squash
dialogparent
windowview
tileseditor
overview
highlightwindow
blendchanges
startupfeedback
systembell
screentransform
kscreen

Currently Active Effects:
-------------------------
blur

Effect Settings:
----------------
shakecursor:

outputlocator:

colorpicker:

zoom:
zoomFactor: 1.2
mouseTracking: 0
focusDelay: 350
moveFactor: 20
targetZoom: 1

screenedge:

blur:

logout:
pluginId: logout
isActiveFullScreenEffect: false

login:
pluginId: login
isActiveFullScreenEffect: false

sessionquit:
pluginId: sessionquit
isActiveFullScreenEffect: false

slidingpopups:
slideInDuration: 50
slideOutDuration: 50

slidingnotifications:

windowaperture:
pluginId: windowaperture
isActiveFullScreenEffect: false

slide:
horizontalGap: 45
verticalGap: 20
slideBackground: true

maximize:
pluginId: maximize
isActiveFullScreenEffect: false

fadingpopups:
pluginId: fadingpopups
isActiveFullScreenEffect: false

fullscreen:
pluginId: fullscreen
isActiveFullScreenEffect: false

frozenapp:
pluginId: frozenapp
isActiveFullScreenEffect: false

scale:
pluginId: scale
isActiveFullScreenEffect: false

dimscreen:
pluginId: dimscreen
isActiveFullScreenEffect: false

squash:
pluginId: squash
isActiveFullScreenEffect: false

dialogparent:
pluginId: dialogparent
isActiveFullScreenEffect: false

windowview:
activeView:  
delegate:  
animationDuration: 75
ignoreMinimized: false
mode: ModeAllDesktops
partialActivationFactor: 0
gestureInProgress: false
searchText:  
selectedIds:  

tileseditor:
activeView:  
delegate:  
animationDuration: 200

overview:
activeView:  
delegate:  
animationDuration: 75
ignoreMinimized: false
filterWindows: true
organizedGrid: true
overviewPartialActivationFactor: 0
overviewGestureInProgress: false
transitionPartialActivationFactor: 0
transitionGestureInProgress: false
gridPartialActivationFactor: 0
gridGestureInProgress: false
searchText:  

highlightwindow:

blendchanges:

startupfeedback:
type: 1

systembell:

screentransform:

kscreen:


Loaded Plugins:
---------------
BounceKeysPlugin
KeyNotificationPlugin
MouseKeysPlugin
SlowKeysPlugin
StickyKeysPlugin
TouchpadShortcutsPlugin
buttonsrebind
eis
gamecontroller
krunnerintegration
nightlight
screencast
screenshot

Available Plugins:
------------------
BounceKeysPlugin
KeyNotificationPlugin
MouseKeysPlugin
SlowKeysPlugin
StickyKeysPlugin
TouchpadShortcutsPlugin
buttonsrebind
eis
gamecontroller
krunnerintegration
nightlight
screencast
screenshot

kscreen-doctor -i

Environment: 
  * KSCREEN_BACKEND           : [not set]
  * KSCREEN_BACKEND_INPROCESS : [not set]
  * KSCREEN_LOGGING           : [not set]
Logging to                : [logging disabled]
Preferred KScreen backend : KSC_KWayland.so
Available KScreen backends:
  * KSC_Fake.so: /usr/lib/qt6/plugins/kf6/kscreen/KSC_Fake.so
  * KSC_KWayland.so: /usr/lib/qt6/plugins/kf6/kscreen/KSC_KWayland.so
  * KSC_XRandR.so: /usr/lib/qt6/plugins/kf6/kscreen/KSC_XRandR.so

xrandr --listmonitors

WARNING: running xrandr against an Xwayland server. See the xrandr man page for details.
Monitors: 2
 0: +*DP-1 2560/698x1440/393+1920+0  DP-1
 1: +DP-4 1920/598x1080/336+0+0  DP-4

Last edited by Gass (2026-06-23 16:13:53)

seth · 2026-06-23 18:57:46

"kscreen-doctor -o"

Wild guess, https://bbs.archlinux.org/viewtopic.php … 9#p2302379 ?
(notably atomic modesetting)
And

kscreen-doctor output.1.vrrpolicy.never
kscreen-doctor output.2.vrrpolicy.never
kscreen-doctor output.3.vrrpolicy.never

Also check the system journal for errors from kwin - the problem seems to be to copy the textures to the APU

Edit: also https://wiki.archlinux.org/title/KDE#Me … -specific) - what if you run the session on the APU (regular prime)?

Last edited by seth (2026-06-23 18:59:00)

Gass · 2026-06-23 20:03:05

I tried both suggestions, prioritizing the dGPU didn't do it, but after changing one of the variables proposed in the other thread it works:

~/.config/environment.d/90-wayland.conf

KWIN_DRM_USE_MODIFIERS=0

and it doesn't seem to be any weird CPU usage, and both GPUs show some usage when I fiddle on the monitor attached to each.

I'm off to find out what those variables actually do and try to learn something.

Thank you very much for you help.

Last edited by Gass (2026-06-23 20:19:59)

seth · 2026-06-23 20:14:29

Primarily figure which of them is critical (or you actually need the combo)

Gass · 2026-06-23 20:19:25

You are right, seems that just

KWIN_DRM_USE_MODIFIERS=0

is the one I need for it to work as expected. Thanks once again.

seth · 2026-06-23 20:35:43

There're probably error messages about that in the journal you'll have to provide at https://bugs.kde.org/
(The problem seems uncommon for two AMD chips)

Gass · 2026-06-23 21:11:00

I think it's already been worked on https://bugs.kde.org/show_bug.cgi?id=521716
I had no idea where to begin but a search on KDE bugs showed something that seems very similar, I'll be following that and try to pitch in if I can.

Arch Linux

#1 2026-06-23 13:37:13

[SOLVED] KDE Wayland 2nd screen is black+mouse cursor

#2 2026-06-23 15:20:14

Re: [SOLVED] KDE Wayland 2nd screen is black+mouse cursor

#3 2026-06-23 15:30:08

Re: [SOLVED] KDE Wayland 2nd screen is black+mouse cursor

#4 2026-06-23 18:57:46

Re: [SOLVED] KDE Wayland 2nd screen is black+mouse cursor

#5 2026-06-23 20:03:05

Re: [SOLVED] KDE Wayland 2nd screen is black+mouse cursor

#6 2026-06-23 20:14:29

Re: [SOLVED] KDE Wayland 2nd screen is black+mouse cursor

#7 2026-06-23 20:19:25

Re: [SOLVED] KDE Wayland 2nd screen is black+mouse cursor

#8 2026-06-23 20:35:43

Re: [SOLVED] KDE Wayland 2nd screen is black+mouse cursor

#9 2026-06-23 21:11:00

Re: [SOLVED] KDE Wayland 2nd screen is black+mouse cursor

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