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johnny2600

Member

Registered: 2024-06-29

Posts: 3

KDE 6 on Samsung uj590 monitor loses resolution after screen lock

Hi all!

I'm having persistent issues since I upgraded to KDE 6 where my system loses the highest monitor resolution after my screen locks or hibernates.  This happens every single time I log in after a screen lock.

A reboot fixes everything.  However, anytime my screen locks, either by manually locking or auto locking, the resolution will be lost on the next login.  Hibernate drops my resolution as well, although I have this feature disabled currently.

After a screen lock, my monitor resolution will vary, but will always be lower than the desired resolution of 3840x2160.  When I try to change this lower resolution in system settings, the 3840x2160 resolution is no longer present in the list of options.  Because I have to do this so often, I've started using the kscreen-doctor cli command to set the resolution.  I've found that if I turn my monitor off and on numerous times (usually between 1 and 6 times) and run the kscreen-doctor cli command each time to try to set the resolution to 3840x2160, it eventually works.  Here's an example of the process and output:

$ kscreen-doctor output.DP-2.mode.3840x2160@30
Output mode 3840x2160@30 not found.
$ kscreen-doctor output.DP-2.mode.3840x2160@30
Output mode 3840x2160@30 not found.
$ kscreen-doctor output.DP-2.mode.3840x2160@30
Output mode 3840x2160@30 not found.
$ kscreen-doctor output.DP-2.mode.3840x2160@30
Output mode 3840x2160@30 not found.
$ kscreen-doctor output.DP-2.mode.3840x2160@30
Output mode 3840x2160@30 not found.
$ kscreen-doctor output.DP-2.mode.3840x2160@30
kscreen.doctor: Taddaaa! Found mode "0" "3840x2160@30"
kscreen.doctor: Output 1 set mode "3840x2160@30"
kscreen.doctor: setop exec returned KScreen::Config( 
KScreen::Output(1, "DP-2", connected enabled priority 1, pos: QPoint(0,0), res: QSize(1024, 768), modeId: "0", scale: 1.25, clone: no, rotation: KScreen::Output::None, followPreferredMode: false) )

I'm using a Samsung uj590 monitor connected via display port to an old Dell Optiplex 9010 desktop.  This is a brand new arch install and I keep it pretty up to date:

Linux host 6.9.3-arch1-1 #1 SMP PREEMPT_DYNAMIC Fri, 31 May 2024 15:14:45 +0000 x86_64 GNU/Linux

Some additional context:

$ pacman -Q | grep kde                       
kde-cli-tools 6.0.5-1
kde-gtk-config 6.0.5-1
kdeclarative 6.2.0-1
kdecoration 6.0.5-1
kded 6.2.0-1
kdeplasma-addons 6.0.5-1
kdesu 6.2.0-1
libblockdev 3.1.1-2
libblockdev-crypto 3.1.1-2
libblockdev-fs 3.1.1-2
libblockdev-loop 3.1.1-2
libblockdev-mdraid 3.1.1-2
libblockdev-nvme 3.1.1-2
libblockdev-part 3.1.1-2
libblockdev-swap 3.1.1-2
polkit-kde-agent 6.0.5-1
qt5-base 5.15.14+kde+r140-1
qt5-declarative 5.15.14+kde+r28-1
qt5-svg 5.15.14+kde+r5-1
qt5-wayland 5.15.14+kde+r57-1
xdg-desktop-portal-kde 6.0.5-1

I haven't been able to identify any clues in the logs, but I do see a lot of entries like this:

Jun 29 11:25:22 plasmashell[1067]: file:///usr/share/plasma/plasmoids/org.kde.plasma.clipboard/contents/ui/TextItemDelegate.qml:20: T
ypeError: Cannot read property 'slice' of undefined
Jun 29 11:25:22 plasmashell[1067]: The cached device pixel ratio value was stale on window update.  Please file a QTBUG which explain
s how to reproduce.
Jun 29 11:25:29 kactivitymanagerd[1071]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
Jun 29 11:25:29 kwalletd6[874]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
Jun 29 11:25:29 systemsettings[912644]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
Jun 29 11:25:29 kded6[1041]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
Jun 29 11:25:29 org_kde_powerdevil[1104]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
Jun 29 11:25:29 konsole[1302]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
Jun 29 11:25:29 xdg-desktop-portal-kde[1105]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
Jun 29 11:25:29 polkit-kde-authentication-agent-1[1103]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
Jun 29 11:25:29 firefox[276769]: Couldn't map window 0x73d85658e640 as subsurface because its parent is not mapped.
Jun 29 11:25:29 plasmashell[276769]: [Parent 276769, Main Thread] WARNING: Couldn't map window 0x73d85658e640 as subsurface because i
ts parent is not mapped.: 'glib warning', file /usr/src/debug/firefox/firefox-126.0.1/toolkit/xre/nsSigHandlers.cpp:187

I'm more than happy to provide any additional information to help solve this problem as it is driving me crazy.

Thanks in advance.

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 24,096

Re: KDE 6 on Samsung uj590 monitor loses resolution after screen lock

Your system multiple weeks out of date, this should be fixed in 6.1 .1

Update your system, reboot and check whether you can reproduce

Last edited by V1del (2024-06-29 19:58:56)

johnny2600

Member

Registered: 2024-06-29

Posts: 3

Re: KDE 6 on Samsung uj590 monitor loses resolution after screen lock

Great suggestion!  Unfortunately, after updating and rebooting, I'm still experiencing the same issue.

kde-cli-tools 6.1.1-1
kde-gtk-config 6.1.1-1
kdeclarative 6.3.0-1
kdecoration 6.1.1-1
kded 6.3.0-1
kdeplasma-addons 6.1.1-1
kdesu 6.3.0-1
libblockdev 3.1.1-2
libblockdev-crypto 3.1.1-2
libblockdev-fs 3.1.1-2
libblockdev-loop 3.1.1-2
libblockdev-mdraid 3.1.1-2
libblockdev-nvme 3.1.1-2
libblockdev-part 3.1.1-2
libblockdev-swap 3.1.1-2
polkit-kde-agent 6.1.1-1
qt5-base 5.15.14+kde+r141-1
qt5-declarative 5.15.14+kde+r28-1
qt5-svg 5.15.14+kde+r5-1
qt5-wayland 5.15.14+kde+r58-1
xdg-desktop-portal-kde 6.1.1-1

johnny2600

Member

Registered: 2024-06-29

Posts: 3

Re: KDE 6 on Samsung uj590 monitor loses resolution after screen lock

This problem persists even after consistent updates to my system.  Just in case there's someone else out there having the same problem, I'm still looking for clues and will post back if I ever find a solution.