Bug 516479 - Time/time zone is incorrect in lock screen for external screen until time changes (e.g. 1 minute has elapsed)
Summary: Time/time zone is incorrect in lock screen for external screen until time cha...
Status: RESOLVED FIXED
Alias: None
Product: plasmashell
Classification: Plasma
Component: Screen locking (other bugs)
Version First Reported In: 6.6.0
Platform: KDE Linux Linux
: HI normal
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL:
Keywords: multiscreen, regression
: 513115 516672 516708 517010 517680 518258 519850 (view as bug list)
Depends on:
Blocks:
 
Reported: 2026-02-21 21:43 UTC by Elyas
Modified: 2026-05-06 18:32 UTC (History)
22 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In: 6.6.5
Sentry Crash Report:


Attachments
workaround patch (1.98 KB, patch)
2026-03-31 18:26 UTC, Mark Harmstone
Details

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Description Elyas 2026-02-21 21:43:49 UTC
SUMMARY
after waking up from sleep, (i use a laptop) the built in monitor shows the correct time, the external one (i have set as primary) shows incorrect time, like the built in one shows 3:30PM and the external one shows 12:30PM, after logging in again, everything is back to being perfect
also when in lockscreen, if the time changes like from 9:29 to 9:30, both become synced

STEPS TO REPRODUCE
1. wait for screen to lock normally
2. keep it locked for a while, even if display turns off
3. look at the lock screen

OBSERVED RESULT
Time is not synced between monitors until the digits change, like after a minute passes, both sync.

EXPECTED RESULT
time should be synced between monitors

SOFTWARE/OS VERSIONS
Operating System: KDE Linux 2026-02-20
KDE Plasma Version: 6.6.80
KDE Frameworks Version: 6.24.0
Qt Version: 6.10.2
Kernel Version: 6.18.9-zen1-2-zen (64-bit)
Graphics Platform: Wayland
Processors: 24 × 13th Gen Intel® Core™ i7-13700HX
Memory: 32 GiB of RAM (31.1 GiB usable)
Graphics Processor: NVIDIA GeForce RTX 4060 Laptop GPU

ADDITIONAL INFORMATION
Comment 1 Nate Graham 2026-02-25 03:15:37 UTC
*** Bug 516672 has been marked as a duplicate of this bug. ***
Comment 2 Nate Graham 2026-02-25 14:43:00 UTC
*** Bug 516708 has been marked as a duplicate of this bug. ***
Comment 3 TraceyC 2026-02-25 18:18:11 UTC
I'm not able to reproduce this on Plasma built from git-master, with or without putting the system to sleep.
I'm also not able to reproduce with Plasma 6.6.1, but I see one of the duplicates (for the time zone, not the time) is on 6.6.1
Comment 4 immerohnegott 2026-02-27 16:03:04 UTC
This was still happening for me on Arch / Plasma 6.6.1 (my specs are in the duplicate bug https://bugs.kde.org/show_bug.cgi?id=516672). Note this was happening with the system being awake but the monitors powering down after inactivity/screenlock.

Interestingly, it seems to have stopped happening after disabling MST on my displays' onboard  menus (both older Dell UltraSharp LCD panels, both connected to the GPU via DisplayPort directly, no daisy-chaining so the MST enablement wasn't doing anything for me).

I noted some oddities in dmesg when the displays were powered back on related to drm and amdgpu, as well as some powerdevil DDC messages in journalctl --user. 

Dmesg:
 2221.315037] [drm] DM_MST: stopping TM on aconnector: 000000000b539075 [id: 104]
[ 2222.129177] [drm] DM_MST: starting TM on aconnector: 000000000b539075 [id: 104]
[ 2222.134729] [drm] DM_MST: DP12, 4-lane link detected
[ 6800.207152] [drm] DM_MST: stopping TM on aconnector: 000000000b539075 [id: 104]
[ 6801.029817] [drm] DM_MST: starting TM on aconnector: 000000000b539075 [id: 104]
[ 6801.035371] [drm] DM_MST: DP12, 4-lane link detected
[ 7007.899875] [drm] DM_MST: stopping TM on aconnector: 000000000b539075 [id: 104]
[ 7008.110274] amdgpu 0000:03:00.0: [drm] REG_WAIT timeout 1us * 100 tries - dcn32_program_compbuf_size line:147

=================
PowerDevil:
Feb 27 09:46:53 cezanne org_kde_powerdevil[19681]: [ 19734] Removing connected display on bus 11
Feb 27 09:46:53 cezanne org_kde_powerdevil[19681]: [ 19734] Emitting DDCA_Display_Status_Event[205.012:  DDCA_EVENT_DISPLAY_DISCONNECTED, card1-DP-5, dref: DDCA_Display_Ref[2], io_path:/dev/i2c-11, ddc working: false]
Feb 27 09:46:53 cezanne org_kde_powerdevil[19681]: [ 19734] Starting 1 callback threads
Feb 27 09:46:53 cezanne org_kde_powerdevil[19681]: [ 19734] libddcutil callback thread 0x7f5774003e40 started
Feb 27 09:46:53 cezanne org_kde_powerdevil[19681]: [ 19734] Started 1 event callback thread(s)
Feb 27 09:46:53 cezanne org_kde_powerdevil[19681]: [ 20616] Invoking callback function 0x7f57a5d4b7f0 for event DDCA_Display_Status_Event[205.012:  DDCA_EVENT_DISPLAY_DISCONNECTED, card1-DP-5, dref: DDCA_Display_Ref[2], io_path:/dev/i2c-11, ddc working: false] in this thread [ 20616]
Feb 27 09:46:53 cezanne org_kde_powerdevil[19681]: [ 19734] Udev event detected
Feb 27 09:46:53 cezanne org_kde_powerdevil[19681]: [ 20616] Callback function 0x7f57a5d4b7f0 for event DDCA_Display_Status_Event[205.012:  DDCA_EVENT_DISPLAY_DISCONNECTED, card1-DP-5, dref: DDCA_Display_Ref[2], io_path:/dev/i2c-11, ddc working: false] complete
Feb 27 09:46:53 cezanne org_kde_powerdevil[19681]: [ 19734] Udev event detected
Feb 27 09:46:53 cezanne org_kde_powerdevil[19681]: [ 19734] Udev event detected
Feb 27 09:46:53 cezanne org_kde_powerdevil[19681]: [ 19734] Udev event detected
=================

Obviously whatever causes *that* isn't likely a Plasma issue, but from my naive understanding it appears to have the effect of hotplugging the display on wake (by hard-resetting the DP link). After disabling MST, the above messages haven't recurred and the times are synced across displays when they come up. So it looks like that DP reset on wake was tripping something up behind the scenes, at least on my machine?

Hopefully the added context helps!
Comment 5 dantmnf 2026-02-27 16:16:47 UTC
(In reply to immerohnegott from comment #4)

DisplayPort monitors may look disconnected from host under DPMS power saving mode, and look like hot-plug on wakeup, which matches the description on my duplicate.

The extra thing is that it can also be triggered by turning one display off and on before idle timeout.
Comment 6 dantmnf 2026-02-27 16:25:04 UTC
Also reproduced on another laptop by connecting an HDMI display.

And yes, it fixes itself automagically on time change like 9:29 to 9:30.
Comment 7 Nate Graham 2026-03-03 12:38:28 UTC
*** Bug 517010 has been marked as a duplicate of this bug. ***
Comment 8 Nick H 2026-03-27 05:26:24 UTC
I am getting this also.
Laptop ✅
External Monitor (usb-C Display Port) ✅ -> after screen wakes from sleep
Auto corrects after minute change ✅

I use an HDMI TV connected to the laptop also and from memory that also shifts the time incorrectly.

SOFTWARE/OS VERSIONS
Operating System: CachyOS Linux 
KDE Plasma Version: 6.6.3
KDE Frameworks Version: 6.24.0
Qt Version: 6.11.0
Kernel Version: 6.19.9-2-cachyos (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 5800H with Radeon Graphics
Memory: 16 GiB of RAM (15.0 GiB usable)
Graphics Processor 1: AMD Radeon Graphics
Graphics Processor 2: NVIDIA GeForce RTX 3060 Laptop GPU
Manufacturer: ASUSTeK COMPUTER INC.
Product Name: ASUS TUF Gaming A15 FA506QM_TUF506QM
Comment 9 Brandon Flores 2026-03-28 19:38:32 UTC
I'm not sure if this should be spun off into a separate issue, but I've had some unexpected changes to the lockscreen on a single monitor setup. I use LC_TIME=C in my locale settings, and until recently the lockscreen and SDDM would show the time in seconds. Now the lockscreen does not show seconds at all, and SDDM (which uses a slightly modified Breeze theme for a monospaced clock font) only updates the time at the top of each minute (the seconds always read :00).

Currently running recently updated Arch Linux with Plasma on Wayland (qt6-base 6.11.0-1, kscreenlocker 6.6.3-1).
Comment 10 artyomisflash 2026-03-29 18:11:59 UTC
Can confirm happening on Plasma 6.6.3 under Arch, same about the LC_TIME=C missing seconds as well. This bug is relevant to me because one of my main monitors (Redmi G24, connected via DP) often freezes in power saving mode, and I have to restart it to make it come back on again, which makes it get disconnected and reconnected.
Comment 11 strudelkuchen 2026-03-31 17:54:53 UTC
I can confirm this too.

Not a laptop.

Desktop with two monitors.

Operating System: CachyOS Linux
KDE Plasma Version: 6.6.3
KDE Frameworks Version: 6.24.0
Qt Version: 6.11.0
Graphics Platform: Wayland

One monitor shows 17:52, the other shows 19:52.

When the time hits 19:53, both show the correct time.
Comment 12 strudelkuchen 2026-03-31 17:55:39 UTC
(In reply to strudelkuchen from comment #11)
> I can confirm this too.
> 
> Not a laptop.
> 
> Desktop with two monitors.
> 
> Operating System: CachyOS Linux
> KDE Plasma Version: 6.6.3
> KDE Frameworks Version: 6.24.0
> Qt Version: 6.11.0
> Graphics Platform: Wayland
> 
> One monitor shows 17:52, the other shows 19:52.
> 
> When the time hits 19:53, both show the correct time.

In case `locale` is relevant:

LANG=en_US.UTF-8
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC=en_DK.UTF-8
LC_TIME=en_DK.UTF-8
LC_COLLATE="en_US.UTF-8"
LC_MONETARY=en_DK.UTF-8
LC_MESSAGES="en_US.UTF-8"
LC_PAPER=en_DK.UTF-8
LC_NAME=en_DK.UTF-8
LC_ADDRESS=en_DK.UTF-8
LC_TELEPHONE=en_DK.UTF-8
LC_MEASUREMENT=en_DK.UTF-8
LC_IDENTIFICATION=en_DK.UTF-8
LC_ALL=
Comment 13 Mark Harmstone 2026-03-31 18:25:04 UTC
I can reproduce this reliably: lock the session (time is in BST), turn off the screen, turn it on again and time is in GMT, wait for the next minute and it returns to BST. This has just started triggering for me, presumably because the clocks changed two days ago.

The commit which introduced this seems to be 4c47c98 ("lookandfeel: Port Clock to libclock") in plasma-workspace. Reverting that fixes the bug.
Comment 14 Mark Harmstone 2026-03-31 18:26:22 UTC
Created attachment 191168 [details]
workaround patch

Patch against plasma-workspace 6.6.3 which removes the bug
Comment 15 Brandon Flores 2026-03-31 19:09:44 UTC
(In reply to Mark Harmstone from comment #14)
> Created attachment 191168 [details]
> workaround patch
> 
> Patch against plasma-workspace 6.6.3 which removes the bug

I was modifying my SDDM theme some time before the attached patch made it to my system, and I think I already encountered this bug. When I was testing the theme modifications I was making with sddm-greeter-qt6 --test-mode, I noticed that for the first second, the clock would display UTC time, and then it would correct itself to my time zone (Central Time, so much more obvious to me) on the next clock update.

In patch 4c47c98, there was a change to the way time was updated - in an attempt to reduce the amount of updates/wakes, the ability to track seconds (which would be enabled if the time format displays seconds) was removed. So when this change was made, aside from breaking the seconds display for anyone using a time format with seconds, the pre-existing time zone bug became much more obvious to everyone.

The cause probably lies elsewhere, but I will advocate for returning clock updates on the second if possible!
Comment 16 TraceyC 2026-03-31 21:25:59 UTC
(In reply to Mark Harmstone from comment #14)
> Created attachment 191168 [details]
> workaround patch
> 
> Patch against plasma-workspace 6.6.3 which removes the bug

Thanks for the patch! The next step is to create a merge request. In the MR, please add BUG: [the number of this Bugzilla ticket] so it gets linked to this report.

https://community.kde.org/Infrastructure/GitLab#Submitting_a_merge_request

If you want to discuss the development work, please reach out in our Matrix channel for new contributors
https://community.kde.org/Get_Involved#New_Contributor?_Say_Hello_In_Matrix
Thanks again!
Comment 17 Mark Harmstone 2026-03-31 21:30:45 UTC
(In reply to TraceyC from comment #16)
> (In reply to Mark Harmstone from comment #14)
> > Created attachment 191168 [details]
> > workaround patch
> > 
> > Patch against plasma-workspace 6.6.3 which removes the bug
> 
> Thanks for the patch! The next step is to create a merge request. In the MR,
> please add BUG: [the number of this Bugzilla ticket] so it gets linked to
> this report.
> 
> https://community.kde.org/Infrastructure/GitLab#Submitting_a_merge_request
> 
> If you want to discuss the development work, please reach out in our Matrix
> channel for new contributors
> https://community.kde.org/Get_Involved#New_Contributor?_Say_Hello_In_Matrix
> Thanks again!

The reason I didn't is clearly the actual solution is to fix libclock, this is just a workaround.
Comment 18 Robert 2026-04-04 01:47:12 UTC
Also experiencing this issue  on Kubuntu 26.04 w/ Plasma 6.6.3 on Wayland.
Comment 19 Marco 2026-04-04 17:28:52 UTC
*** Bug 518258 has been marked as a duplicate of this bug. ***
Comment 20 DeepChirp 2026-04-09 03:28:48 UTC
*** Bug 517680 has been marked as a duplicate of this bug. ***
Comment 21 DeepChirp 2026-04-09 03:38:07 UTC
I have created a Merge Request (https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/6482) that might resolve this issue.
Comment 22 Nate Graham 2026-04-09 14:59:59 UTC
Fixed by DeepChirp for Plasma 6.6.5 with https://invent.kde.org/plasma/plasma-workspace/-/commit/d88ebe550d8f80d6ed5a2962ef0d944371aed1ab!
Comment 23 Nate Graham 2026-05-06 18:31:02 UTC
*** Bug 519850 has been marked as a duplicate of this bug. ***
Comment 24 Nate Graham 2026-05-06 18:32:11 UTC
*** Bug 513115 has been marked as a duplicate of this bug. ***