Created attachment 121215 [details]
screenshot of google chrome

This is related to: https://bugs.kde.org/show_bug.cgi?id=406302

When using 30bit colour and a supported device, there are three issues:

1. The OpenGL Compositor does not work, it crashes immediately if OpenGL 3.1 or OpenGL 2.0 are selected. XRender works fine, but obviously OpenGL would be better.

2. GTK applications colours are completely messed up. Google Chrome is a good example, all the colours are garbled as the previous bug I linked to but for the entire application. 

3. A separate issue, but there currently seems no way to set 10bit colour on Wayland, I was going to test as the problems may not exist there.


Xorg conf:

Section "Screen"
        Identifier "Screen0"
       Device     "Card0"
         Monitor    "Monitor0"


        DefaultDepth 30 
        SubSection "Display"
                Viewport   0 0
                Depth     30
        EndSubSection
EndSection


Hardware: Intel i7 8560u with a DisplayPort monitor and the i915 driver.



output of qdbus org.kde.KWin /KWin org.kde.KWin.supportInformation:


KWin Support Information:
The following information should be used when requesting support on e.g. https://forum.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: 5.16.1
Qt Version: 5.12.4
Qt compile version: 5.12.4
XCB compile version: 1.13.1

Operation Mode: X11 only

Build Options
=============
KWIN_BUILD_DECORATIONS: yes
KWIN_BUILD_TABBOX: yes
KWIN_BUILD_ACTIVITIES: yes
HAVE_DRM: yes
HAVE_GBM: yes
HAVE_EGL_STREAMS: yes
HAVE_X11_XCB: yes
HAVE_EPOXY_GLX: yes
HAVE_WAYLAND_EGL: yes

X11
===
Vendor: The X.Org Foundation
Vendor Release: 12005000
Protocol Version/Revision: 11/0
SHAPE: yes; Version: 0x11
RANDR: yes; Version: 0x14
DAMAGE: yes; Version: 0x11
Composite: yes; Version: 0x4
RENDER: yes; Version: 0xb
XFIXES: yes; Version: 0x50
SYNC: yes; Version: 0x31
GLX: yes; Version: 0x0

Decoration
==========
Plugin: org.kde.breeze
Theme: 
Blur: 0
onAllDesktopsAvailable: false
alphaChannelSupported: true
closeOnDoubleClickOnMenu: false
decorationButtonsLeft: 0, 2
decorationButtonsRight: 6, 3, 4, 5
borderSize: 3
gridUnit: 30
font: Noto Sans,10,-1,5,50,0,0,0,0,0,Regular
smallSpacing: 7
largeSpacing: 30

Platform
==========
Name: KWin::X11StandalonePlatform

Options
=======
focusPolicy: 0
nextFocusPrefersMouse: false
clickRaise: true
autoRaise: false
autoRaiseInterval: 0
delayFocusInterval: 0
shadeHover: false
shadeHoverInterval: 250
separateScreenFocus: false
placement: 4
focusPolicyIsReasonable: true
borderSnapZone: 10
windowSnapZone: 10
centerSnapZone: 0
snapOnlyWhenOverlapping: false
rollOverDesktops: true
focusStealingPreventionLevel: 1
legacyFullscreenSupport: false
operationTitlebarDblClick: 5000
operationMaxButtonLeftClick: 5000
operationMaxButtonMiddleClick: 5015
operationMaxButtonRightClick: 5014
commandActiveTitlebar1: 0
commandActiveTitlebar2: 30
commandActiveTitlebar3: 2
commandInactiveTitlebar1: 4
commandInactiveTitlebar2: 30
commandInactiveTitlebar3: 2
commandWindow1: 7
commandWindow2: 8
commandWindow3: 8
commandWindowWheel: 31
commandAll1: 10
commandAll2: 3
commandAll3: 14
keyCmdAllModKey: 16777251
showGeometryTip: false
condensedTitle: false
electricBorderMaximize: true
electricBorderTiling: true
electricBorderCornerRatio: 0.25
borderlessMaximizedWindows: false
killPingTimeout: 5000
hideUtilityWindowsForInactive: true
inactiveTabsSkipTaskbar: false
autogroupSimilarWindows: false
autogroupInForeground: true
compositingMode: 2
useCompositing: true
compositingInitialized: true
hiddenPreviews: 1
glSmoothScale: 2
xrenderSmoothScale: false
maxFpsInterval: 16666666
refreshRate: 0
vBlankTime: 6000000
glStrictBinding: true
glStrictBindingFollowsDriver: true
glCoreProfile: false
glPreferBufferSwap: 97
glPlatformInterface: 1
windowsBlockCompositing: true

Screen Edges
============
desktopSwitching: false
desktopSwitchingMovingClients: false
cursorPushBackDistance: 1x1
timeThreshold: 150
reActivateThreshold: 350
actionTopLeft: 0
actionTop: 0
actionTopRight: 0
actionRight: 0
actionBottomRight: 0
actionBottom: 0
actionBottomLeft: 0
actionLeft: 0

Screens
=======
Multi-Head: no
Active screen follows mouse:  no
Number of Screens: 2

Screen 0:
---------
Name: DP1
Geometry: 0,0,3840x2160
Scale: 1
Refresh Rate: 30

Screen 1:
---------
Name: HDMI1
Geometry: 84,120,1280x720
Scale: 1
Refresh Rate: 60


Compositing
===========
Compositing is active
Compositing Type: XRender

Loaded Effects:
---------------
kwin4_effect_maximize
zoom
kwin4_effect_login
kwin4_effect_frozenapp
kwin4_effect_morphingpopups
kwin4_effect_squash
kwin4_effect_windowaperture
kwin4_effect_fadingpopups
kwin4_effect_fade
kwin4_effect_translucency
kwin4_effect_dialogparent
kwin4_effect_logout
slidingpopups
slide
screenshot
desktopgrid
presentwindows
highlightwindow
screenedge
kscreen

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

Effect Settings:
----------------
kwin4_effect_maximize:
isActiveFullScreenEffect: false

zoom:
zoomFactor: 1.2
mousePointer: 0
mouseTracking: 0
enableFocusTracking: false
followFocus: true
focusDelay: 350
moveFactor: 20
targetZoom: 1

kwin4_effect_login:
isActiveFullScreenEffect: false

kwin4_effect_frozenapp:
isActiveFullScreenEffect: false

kwin4_effect_morphingpopups:
isActiveFullScreenEffect: false

kwin4_effect_squash:
isActiveFullScreenEffect: false

kwin4_effect_windowaperture:
isActiveFullScreenEffect: false

kwin4_effect_fadingpopups:
isActiveFullScreenEffect: false

kwin4_effect_fade:
isActiveFullScreenEffect: false

kwin4_effect_translucency:
isActiveFullScreenEffect: false

kwin4_effect_dialogparent:
isActiveFullScreenEffect: false

kwin4_effect_logout:
isActiveFullScreenEffect: false

slidingpopups:
slideInDuration: 150
slideOutDuration: 250

slide:
duration: 500
horizontalGap: 45
verticalGap: 20
slideDocks: false
slideBackground: true

screenshot:

desktopgrid:
zoomDuration: 300
border: 10
desktopNameAlignment: 0
layoutMode: 0
customLayoutRows: 2
usePresentWindows: true

presentwindows:
layoutMode: 0
showCaptions: true
showIcons: true
doNotCloseWindows: false
ignoreMinimized: false
accuracy: 20
fillGaps: true
fadeDuration: 150
showPanel: false
leftButtonWindow: 1
rightButtonWindow: 2
middleButtonWindow: 0
leftButtonDesktop: 2
middleButtonDesktop: 0
rightButtonDesktop: 0

highlightwindow:

screenedge:

kscreen: