Bug 506696 - Incorrectly detected external screen refresh rate after upgrade to 6.4.2
Summary: Incorrectly detected external screen refresh rate after upgrade to 6.4.2
Status: RESOLVED UPSTREAM
Alias: None
Product: kwin
Classification: Plasma
Component: general (other bugs)
Version First Reported In: 6.4.2
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords: regression
Depends on:
Blocks:
 
Reported: 2025-07-06 23:21 UTC by elman
Modified: 2025-08-07 22:03 UTC (History)
3 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments

Note You need to log in before you can comment on or make changes to this bug.
Description elman 2025-07-06 23:21:42 UTC
SUMMARY
I'm using Plasma and after upgrade to 6.4.2, my laptop randomly either restarts or completely freezes after 10 to 20 minutes of using external screen. When laptop reboots, I can't see anything in logs, when laptop freezes, I see this:

july 07 11:06:28 myhost kernel: CPU#0 Utilization every 4s during lockup:
july 07 11:06:28 myhost kernel:  #1: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:28 myhost kernel:  #2: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:28 myhost kernel:  #3: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:28 myhost kernel:  #4: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:28 myhost kernel:  #5: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:28 myhost kernel: watchdog: BUG: soft lockup - CPU#12 stuck for 26s! [Compositor:11098]
july 07 11:06:28 myhost kernel: CPU#12 Utilization every 4s during lockup:
july 07 11:06:28 myhost kernel:  #1: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:28 myhost kernel:  #2: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:28 myhost kernel:  #3: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:28 myhost kernel:  #4: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:28 myhost kernel:  #5: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:32 myhost kernel: watchdog: BUG: soft lockup - CPU#2 stuck for 23s! [Backgro~Pool #1:29869]
july 07 11:06:32 myhost kernel: CPU#2 Utilization every 4s during lockup:
july 07 11:06:32 myhost kernel:  #1: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:32 myhost kernel:  #2: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:32 myhost kernel:  #3: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:32 myhost kernel:  #4: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:32 myhost kernel:  #5: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:36 myhost kernel: watchdog: BUG: soft lockup - CPU#6 stuck for 22s! [DOM Worker:29906]
july 07 11:06:36 myhost kernel: CPU#6 Utilization every 4s during lockup:
july 07 11:06:36 myhost kernel:  #1: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:36 myhost kernel:  #2: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:36 myhost kernel:  #3: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:36 myhost kernel:  #4: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:36 myhost kernel:  #5: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:40 myhost kernel: watchdog: BUG: soft lockup - CPU#5 stuck for 22s! [pool-1:46891]
july 07 11:06:40 myhost kernel: CPU#5 Utilization every 4s during lockup:
july 07 11:06:40 myhost kernel:  #1: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:40 myhost kernel:  #2: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:40 myhost kernel:  #3: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:40 myhost kernel:  #4: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:40 myhost kernel:  #5: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:44 myhost kernel: watchdog: BUG: soft lockup - CPU#9 stuck for 22s! [kded6:6236]
july 07 11:06:44 myhost kernel: CPU#9 Utilization every 4s during lockup:
july 07 11:06:44 myhost kernel:  #1: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:44 myhost kernel:  #2: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:44 myhost kernel:  #3: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:44 myhost kernel:  #4: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:44 myhost kernel:  #5: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:48 myhost kernel: watchdog: BUG: soft lockup - CPU#11 stuck for 23s! [Isolated Web Co:29917]
july 07 11:06:48 myhost kernel: CPU#11 Utilization every 4s during lockup:
july 07 11:06:48 myhost kernel:  #1: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:48 myhost kernel:  #2: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:48 myhost kernel:  #3: 100% system,      0% softirq,     1% hardirq,     0% idle
july 07 11:06:48 myhost kernel:  #4: 100% system,      0% softirq,     0% hardirq,     0% idle
july 07 11:06:48 myhost kernel:  #5: 100% system,      0% softirq,     1% hardirq,     0% idle

STEPS TO REPRODUCE
1. Start plasma
2. Connect second screen via HDMI
3. Wait

OBSERVED RESULT
Laptop restarts or freezes

SOFTWARE/OS VERSIONS
Operating System: EndeavourOS 
KDE Plasma Version: 6.4.2
KDE Frameworks Version: 6.15.0
Qt Version: 6.9.1
Kernel Version: 6.15.5-zen1-1-zen (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 5800H with Radeon Graphics
Memory: 32 GiB of RAM (30.7 GiB usable)
Graphics Processor 1: AMD Radeon Graphics
Graphics Processor 2: llvmpipe

ADDITIONAL INFORMATION
External screen is connected via HDMI, which is connected to dedicated NVIDIA with proprietary drivers.

KWin Support Information:
The following information should be used when requesting support on e.g. https://discuss.kde.org.
It provides information about the currently running instance, which options are used,
what OpenGL driver and which effects are running.
Please post the information provided underneath this introductory text to a paste bin service
like https://paste.kde.org instead of pasting into support threads.

==========================

Version
=======
KWin version: 6.4.2
Qt Version: 6.9.1
Qt compile version: 6.9.1
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: 12401008
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: 
Plugin recommends border size: None
onAllDesktopsAvailable: true
alphaChannelSupported: true
closeOnDoubleClickOnMenu: false
decorationButtonsLeft: 0, 2
decorationButtonsRight: 6, 3, 4, 5
borderSize: 0
gridUnit: 12
font: Fira Sans Condensed ExtraBold,11,-1,5,800,0,0,0,0,0,0,0,0,0,0,1,Regular
smallSpacing: 3
largeSpacing: 12

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

Cursor
======
themeName: phinger-cursors-dark
themeSize: 24

Options
=======
focusPolicy: ClickToFocus
xwaylandCrashPolicy: 1
xwaylandMaxCrashCount: 3
nextFocusPrefersMouse: false
clickRaise: true
autoRaise: false
autoRaiseInterval: 0
delayFocusInterval: 0
shadeHover: false
shadeHoverInterval: 250
separateScreenFocus: true
placement: 5
activationDesktopPolicy: SwitchToOtherDesktop
focusPolicyIsReasonable: true
borderSnapZone: 10
windowSnapZone: 10
centerSnapZone: 0
snapOnlyWhenOverlapping: false
edgeBarrier: 100
cornerBarrier: 1
rollOverDesktops: false
focusStealingPreventionLevel: 1
operationTitlebarDblClick: 5000
operationMaxButtonLeftClick: 5000
operationMaxButtonMiddleClick: 5015
operationMaxButtonRightClick: 5014
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
electricBorderCornerRatio: 0.25
borderlessMaximizedWindows: false
killPingTimeout: 5000
compositingMode: 1
allowTearing: true
interactiveWindowMoveEnabled: true

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: 2

Screen 0:
---------
Name: eDP-1
Enabled: 1
Geometry: 0,0,1920x1200
Physical size: 344x215mm
Scale: 2
Refresh Rate: 60000
Adaptive Sync: incapable
Screen 1:
---------
Name: HDMI-A-1
Enabled: 1
Geometry: 1920,0,1920x1080
Physical size: 527x296mm
Scale: 1
Refresh Rate: 100047
Adaptive Sync: incapable

Compositing
===========
Compositing is active
Compositing Type: OpenGL
OpenGL vendor string: AMD
OpenGL renderer string: AMD Radeon Graphics (radeonsi, renoir, ACO, DRM 3.63, 6.15.5-zen1-1-zen)
OpenGL version string: 4.6 (Core Profile) Mesa 25.1.5-arch1.1
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: 25.1.5
X server version: 1.24.1
Linux kernel version: 6.15.5
Direct rendering: Requires strict binding: no
Virtual Machine:  no
OpenGL 2 Shaders are used

Loaded Effects:
---------------
shakecursor
screenshot
outputlocator
colorpicker
zoom
screenedge
blur
contrast
sessionquit
logout
login
slidingpopups
windowaperture
slide
kwin6_effect_glitch
kwin4_effect_geometry_change
squash
maximize
fullscreen
frozenapp
fadingpopups
dimscreen
dialogparent
wobblywindows
windowview
tileseditor
overview
highlightwindow
blendchanges
startupfeedback
systembell
screentransform
kscreen

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

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

screenshot:

outputlocator:

colorpicker:

zoom:
zoomFactor: 1.2
mousePointer: 0
mouseTracking: 0
focusTrackingEnabled: false
textCaretTrackingEnabled: false
focusDelay: 350
moveFactor: 20
targetZoom: 1

screenedge:

blur:

contrast:

sessionquit:
pluginId: sessionquit
isActiveFullScreenEffect: false

logout:
pluginId: logout
isActiveFullScreenEffect: false

login:
pluginId: login
isActiveFullScreenEffect: false

slidingpopups:
slideInDuration: 200
slideOutDuration: 200

windowaperture:
pluginId: windowaperture
isActiveFullScreenEffect: false

slide:
horizontalGap: 45
verticalGap: 20
slideBackground: true

kwin6_effect_glitch:
pluginId: kwin6_effect_glitch
isActiveFullScreenEffect: false

kwin4_effect_geometry_change:
pluginId: kwin4_effect_geometry_change
isActiveFullScreenEffect: false

squash:
pluginId: squash
isActiveFullScreenEffect: false

maximize:
pluginId: maximize
isActiveFullScreenEffect: false

fullscreen:
pluginId: fullscreen
isActiveFullScreenEffect: false

frozenapp:
pluginId: frozenapp
isActiveFullScreenEffect: false

fadingpopups:
pluginId: fadingpopups
isActiveFullScreenEffect: false

dimscreen:
pluginId: dimscreen
isActiveFullScreenEffect: false

dialogparent:
pluginId: dialogparent
isActiveFullScreenEffect: false

wobblywindows:
stiffness: 0.15
drag: 0.8
moveFactor: 0.1
xTesselation: 20
yTesselation: 20
minVelocity: 0
maxVelocity: 1000
stopVelocity: 0.5
minAcceleration: 0
maxAcceleration: 1000
stopAcceleration: 0.5
moveWobble: true
resizeWobble: true

windowview:
activeView: 
delegate: 
animationDuration: 300
ignoreMinimized: false
mode: 
partialActivationFactor: 0
gestureInProgress: false
searchText: 
selectedIds: 

tileseditor:
activeView: 
delegate: 
animationDuration: 200

overview:
activeView: 
delegate: 
animationDuration: 300
ignoreMinimized: false
filterWindows: true
organizedGrid: true
overviewPartialActivationFactor: 0
overviewGestureInProgress: false
transitionPartialActivationFactor: 0
transitionGestureInProgress: false
gridPartialActivationFactor: 0
gridGestureInProgress: false
desktopOffset: 
searchText: 

highlightwindow:

blendchanges:

startupfeedback:
type: 1

systembell:

screentransform:

kscreen:


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

Available Plugins:
------------------
BounceKeysPlugin
KeyNotificationPlugin
MouseKeysPlugin
StickyKeysPlugin
TouchpadShortcutsPlugin
buttonsrebind
eis
krunnerintegration
nightlight
screencast
Comment 1 elman 2025-07-07 21:23:55 UTC
It seems that issue was with refresh rate of my secondary screen. It is 75 Hz screen and before Plasma 6.4.2 it was correctly detected. However, Plasma 6.4.2 reported it's 100 Hz screen and set that refresh rate which caused reboots and freezes. After I set 75 Hz, everything was OK.

Here's EDID of given screen:

# card0-HDMI-A-1 #######################
Block 0, Base EDID:
  EDID Structure Version & Revision: 1.3
  Vendor & Product Identification:
    Manufacturer: AUS
    Model: 9285
    Serial Number: <removed>
    Made in: week 51 of 2022
  Basic Display Parameters & Features:
    Digital display
    Maximum image size: 53 cm x 30 cm
    Gamma: 2.20
    DPMS levels: Off
    RGB color display
    First detailed timing is the preferred timing
  Color Characteristics:
    Red  : 0.6503, 0.3281
    Green: 0.3115, 0.6191
    Blue : 0.1513, 0.0468
    White: 0.3134, 0.3291
  Established Timings I & II:
    IBM     :   720x400    70.081663 Hz   9:5     31.467 kHz     28.320000 MHz
    DMT 0x04:   640x480    59.940476 Hz   4:3     31.469 kHz     25.175000 MHz
    Apple   :   640x480    66.666667 Hz   4:3     35.000 kHz     30.240000 MHz
    DMT 0x05:   640x480    72.808802 Hz   4:3     37.861 kHz     31.500000 MHz
    DMT 0x06:   640x480    75.000000 Hz   4:3     37.500 kHz     31.500000 MHz
    DMT 0x08:   800x600    56.250000 Hz   4:3     35.156 kHz     36.000000 MHz
    DMT 0x09:   800x600    60.316541 Hz   4:3     37.879 kHz     40.000000 MHz
    DMT 0x0a:   800x600    72.187572 Hz   4:3     48.077 kHz     50.000000 MHz
    DMT 0x0b:   800x600    75.000000 Hz   4:3     46.875 kHz     49.500000 MHz
    Apple   :   832x624    74.551266 Hz   4:3     49.726 kHz     57.284000 MHz
    DMT 0x10:  1024x768    60.003840 Hz   4:3     48.363 kHz     65.000000 MHz
    DMT 0x11:  1024x768    70.069359 Hz   4:3     56.476 kHz     75.000000 MHz
    DMT 0x12:  1024x768    75.028582 Hz   4:3     60.023 kHz     78.750000 MHz
    DMT 0x24:  1280x1024   75.024675 Hz   5:4     79.976 kHz    135.000000 MHz
    Apple   :  1152x870    75.061550 Hz 192:145   68.681 kHz    100.000000 MHz
  Standard Timings:
    DMT 0x55:  1280x720    60.000000 Hz  16:9     45.000 kHz     74.250000 MHz
    DMT 0x20:  1280x960    60.000000 Hz   4:3     60.000 kHz    108.000000 MHz
    DMT 0x23:  1280x1024   60.019740 Hz   5:4     63.981 kHz    108.000000 MHz
    DMT 0x2f:  1440x900    59.887445 Hz  16:10    55.935 kHz    106.500000 MHz
    DMT 0x3a:  1680x1050   59.954250 Hz  16:10    65.290 kHz    146.250000 MHz
    DMT 0x15:  1152x864    75.000000 Hz   4:3     67.500 kHz    108.000000 MHz
    DMT 0x1c:  1280x800    59.810326 Hz  16:10    49.702 kHz     83.500000 MHz
  Detailed Timing Descriptors:
    DTD 1:  1920x1080   60.000000 Hz  16:9     67.500 kHz    148.500000 MHz (527 mm x 296 mm)
                 Hfront   88 Hsync  44 Hback  148 Hpol P
                 Vfront    4 Vsync   5 Vback   36 Vpol P
    Display Range Limits:
      Monitor ranges (GTF): 48-100 Hz V, 30-120 kHz H, max dotclock 340 MHz
    Display Product Name: 'VA24EHF'
    Display Product Serial Number: '<removed>'
  Extension blocks: 1
Checksum: 0xa3

----------------

Block 1, CTA-861 Extension Block:
  Revision: 3
  Underscans IT Video Formats by default
  Supports YCbCr 4:4:4
  Supports YCbCr 4:2:2
  Native detailed modes: 1
  Video Data Block:
    VIC   1:   640x480    59.940476 Hz   4:3     31.469 kHz     25.175000 MHz
    VIC   3:   720x480    59.940060 Hz  16:9     31.469 kHz     27.000000 MHz
    VIC   2:   720x480    59.940060 Hz   4:3     31.469 kHz     27.000000 MHz
    VIC   4:  1280x720    60.000000 Hz  16:9     45.000 kHz     74.250000 MHz
    VIC  18:   720x576    50.000000 Hz  16:9     31.250 kHz     27.000000 MHz
    VIC  17:   720x576    50.000000 Hz   4:3     31.250 kHz     27.000000 MHz
    VIC  19:  1280x720    50.000000 Hz  16:9     37.500 kHz     74.250000 MHz
    VIC  16:  1920x1080   60.000000 Hz  16:9     67.500 kHz    148.500000 MHz (native)
    VIC  31:  1920x1080   50.000000 Hz  16:9     56.250 kHz    148.500000 MHz
  Video Capability Data Block:
    YCbCr quantization: Selectable (via AVI YQ)
    RGB quantization: Selectable (via AVI Q)
    PT scan behavior: Always Underscanned
    IT scan behavior: Always Underscanned
    CE scan behavior: Always Underscanned
  Detailed Timing Descriptors:
    DTD 2:  1366x768    59.789541 Hz 683:384   47.712 kHz     85.500000 MHz (527 mm x 296 mm)
                 Hfront   70 Hsync 143 Hback  213 Hpol P
                 Vfront    3 Vsync   3 Vback   24 Vpol P
    DTD 3:  1280x768    59.870228 Hz   5:3     47.776 kHz     79.500000 MHz (527 mm x 296 mm)
                 Hfront   64 Hsync 128 Hback  192 Hpol N
                 Vfront    3 Vsync   7 Vback   20 Vpol P
    DTD 4:  1920x1080  100.047246 Hz  16:9    109.952 kHz    228.700000 MHz (527 mm x 296 mm)
                 Hfront   48 Hsync  32 Hback   80 Hpol P
                 Vfront    3 Vsync   5 Vback   11 Vpol P
    DTD 5:  1920x1080   74.972503 Hz  16:9     83.894 kHz    174.500000 MHz (527 mm x 296 mm)
                 Hfront   48 Hsync  32 Hback   80 Hpol P
                 Vfront    3 Vsync   5 Vback   31 Vpol N
Checksum: 0xb4

----------------

EDID conformity: PASS
Comment 2 TraceyC 2025-07-11 20:03:13 UTC
Setting to kwin
Comment 3 Zamundaaa 2025-08-07 18:00:16 UTC
(In reply to elman from comment #1)
> It seems that issue was with refresh rate of my secondary screen. It is 75
> Hz screen and before Plasma 6.4.2 it was correctly detected. However, Plasma
> 6.4.2 reported it's 100 Hz screen and set that refresh rate which caused
> reboots and freezes.
KWin doesn't decide on available refresh rates, the kernel driver does. Also, the EDID actually says it's a 100Hz screen.
> 1920x1080  100.047246 Hz

Either way, the freeze and random reboots are definitely something in the kernel driver, so please report it at https://forums.developer.nvidia.com/c/gpu-graphics/linux
Comment 4 elman 2025-08-07 22:03:52 UTC
Interesting. Thank you for investigating.