Monitor Periodically Black After Plasma 6.7 Upgrade

Help
1

I was told posting here is preferred since I can’t predictably reproduce this bug, and I’ll try to provide all relevant information, but please let me know if I should direct this elsewhere or if more background is needed.

Issue

After updating to Plasma 6.7.1, I started to notice my monitor periodically go black while using it. The panel turns off for anywhere from maybe 2 to 5 seconds seemingly at random before returning. The computer works uninterrupted and registers actions and keystrokes as if nothing happened. The only major thing that changed the day the problem started was the Plasma upgrade, and it has been happening at unpredictable times since then.

The issue persists through many reboots of system and monitor, a subsequent upgrade from Ultramarine Linux 43 to 44 (around a week after the Plasma upgrade), and now an upgrade to ask.

Hardware Info

This info comes from fastfetch, I will note that this PC only has integrated Intel 530 graphics.

OS: Ultramarine Linux 44 (Plasma Edition) x86_64
Host: HP EliteDesk 800 G3 DM 35W
Kernel: Linux 7.0.14-201.fc44.x86_64
Shell: zsh 5.9
Display (27E6QC): 2560x1440 in 27", 144 Hz [External]
DE: KDE Plasma 6.7.2
WM: KWin (Wayland)
Terminal: konsole 26.4.3
CPU: Intel(R) Core(TM) i5-6600T (4) @ 3.50 GHz
GPU: Intel HD Graphics 530 @ 1.10 GHz [Integrated]

Monitor: 27E6QC KOORUI 1440p monitor running at 144hz, connected via DisplayPort. This is additional info about the monitor copied from fastfetch -c all.

Brightness (27E6QC): 80% [Built-in]
Monitor (27E6QC): 2560x1440 px @ 144 Hz - 597x336 mm (26.97 inches, 108.90 ppi)

Previous Attempts

  • My first troubleshooting ideas were system reboots, fully unplugging and powering off the monitor, and making sure cables were connected properly; I believe I did all of this well enough and still see it.

  • I initially thought the issue could be VRR since I’ve heard that can cause issues, and the monitor has a FreeSync setting (which was off, but the problem persists when it’s on), but after a bit of searching it looks like my integrated Intel graphics cannot support that. No form of VRR appears to be on using VRRTest, so that monitor setting apparently does nothing anyway.

    • I did hear something about KWin toggling VRR when a program is in fullscreen mode, and the blackouts look like the panel is briefly shutting off to apply a setting change, so maybe there’s still something like that?

  • I plugged in an older office monitor through DisplayPort and used it for a while to check for the issue, didn’t notice anything but can’t be sure given how sporadic it is. I also used this same PC and monitor on a live image of an OS with an older version of Plasma, and again didn’t notice anything. I can’t say these conclusively narrow down the problem source between Plasma 6.7, my install, the monitor, or interactions between those.

  • I was given instructions on how to search/grep dmesg and /var/log/messages (I’m not particularly experienced but I had someone looking with me) and it didn’t look like there were any errors or logs when it happens.

I would appreciate any input on preliminary things to try or thoughts on what could be happening, and I’ll try my best to provide any information requested. Thanks!

2

@FyraLoyalist:

First, welcome to the KDE Discuss Forum.

Now that you mention it, on this system I noticed a similar effect a few Tumbleweed snapshots ago (over the last few weeks) but since last Friday, the issue seems to have disappeared.

 > kinfo
Operating System: openSUSE Tumbleweed 20260703
KDE Plasma Version: 6.7.2
KDE Frameworks Version: 6.27.0
Qt Version: 6.11.1
Kernel Version: 7.1.2-1-default (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 8600G w/ Radeon 760M Graphics
Memory: 34 GB of RAM (32.8 GB usable)
Graphics Processor: AMD Radeon 760M Graphics
 >

Please note that, last week – Calender Week 27 – there were 4 Tumbleweed snapshots published.
And, somewhere in the updates, there was something which seems to have resolved this issue.

3

I seem to still have this issue and am still unclear what causes it, and I don’t think any updates fixed it. I left this computer for about a week and I’m back in town today; I’ve just updated to Plasma 6.7.3, but I’ve observed the issue again already.

I did notice that this only happens in maximized windows as far as I know. If I keep a window floating in the middle of the screen, I have never observed it happening, but it comes back when I maximize a browser or other program to check it. I of course can’t confirm it could never happen without a maximized window since it’s so sporadic, but I saw enough to be quite confident several days of the week before I left.

4

What is your Adaptive Sync set to? Does it go away if you set it to Never or Always?

5

I saw that there should be an Adaptive Sync setting in the Display Configuration page in Plasma settings, but that is not present; maybe it’s only there when VRR is supported?

The “FreeSync Premium” setting on the monitor itself does not change this behavior, but after troubleshooting for a while it appeared that no variable refresh rate was supported by my setup (although maybe the testing mentioned in my initial post missed something).

That being said, I still suspect it’s something like this. Mostly because the blackouts look exactly like the monitor refreshing to switch adaptive sync or something similar on and off, or at least trying to even though it may not actually work on my machine.

6

@Yonder5228:

Aahh!! Thank you!
I’ve been plagued for some time now by a small amount of screen flickering when viewing photographs in full screen mode – which didn’t happen if, I used the window’s “Maximize” button …

  • I’ve now set the “Adaptive Sync” to “Never” – issue solved …
7

This still makes me think it’s Adaptive Sync, as I initially thought this was something related to variable refresh rate and @Yonder5228 seems to have the solution, but I still cannot find an Adaptive Sync setting in Plasma Settings. I thought the setting was here under Display Configuration for devices and monitors that support VRR (which my computer shouldn’t in this case). But is it possible this is still the issue, and if so is there a way to change the setting elsewhere?

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image1041×669 57 KB

8

Still having this issue, still think it’s Adaptive Sync being on despite no VRR support, and still don’t have the Adaptive Sync setting available in Display Configuration. Is there a way to disable it when the setting isn’t shown?

I’m getting more and more confident that the issue is the system toggling VRR. Despite the hardware not supporting it, I can manually turn on FreeSync in my monitor which is what I think it’s doing, causes the same blackout (even though yes the setting doesn’t change anything).

9

Talked through this with someone, found a couple issues.

These messages appear and directly coincide with SOME of the blackouts, but several of them happened without logs (two just happened while drafting this and no further logs appeared).

Errors selected from sudo dmesg:

[  190.154255] i915 0000:00:02.0: [drm] *ERROR* Atomic update failure on pipe A (start=26124 end=26125) time 261 us, min 1418, max 1439, scanline start 1387, end 1442
[  496.126211] i915 0000:00:02.0: [drm] *ERROR* CPU pipe A FIFO underrun
[10354.803331] i915 0000:00:02.0: [drm] *ERROR* CPU pipe A FIFO underrun

Second, I was told to look for other display settings which cause the panel to turn off to apply them, and I found “RGB range:” and “Limit color resolution to:”. Both were on “Automatic”. Changed both of those to non-automatic values, initially thought that solved the problem but the blackouts are still happening, including the one that was last in the dmesg logs above.

Feel like this is not actually just an issue with the system trying to toggle VRR, and maybe the Adaptive Sync setting not being visible is not the main obstacle since it appears to not be wrongly enabled.

To tie up my investigation into it being VRR, here is what I found so far. An excerpt from /home/(my username)/.config/kwinoutputconfig.json showing this monitor’s vrrPolicy as “Never”:

            {
                "abmLevel": 0,
                "allowDdcCi": true,
                "allowSdrSoftwareBrightness": false,
                "autoBrightnessCurve": [
                    0,
                    0,
                    0,
                    0,
                    0,
                    0,
                    0,
                    0,
                    0,
                    0,
                    0
                ],
                "autoRotation": "InTabletMode",
                "automaticBrightness": false,
                "brightness": 0.8,
                "colorPowerTradeoff": "PreferEfficiency",
                "colorProfileSource": "sRGB",
                "connectorName": "DP-2",
                "customModes": [
                ],
                "detectedDdcCi": true,
                "edidHash": "7dd8025ccb9eb8ddd9b7532b93764e96",
                "edidIdentifier": "HKC 10038 0 51 2022 0",
                "edrPolicy": "always",
                "hdrColorProfileSource": "EDID",
                "hdrIccProfilePath": "",
                "highDynamicRange": false,
                "iccProfilePath": "",
                "maxBitsPerColor": 10,
                "mode": {
                    "flags": 0,
                    "height": 1440,
                    "refreshRate": 144000,
                    "width": 2560
                },
                "overscan": 0,
                "rgbRange": "Full",
                "scale": 1,
                "sdrBrightness": 200,
                "sdrGamutWideness": 0,
                "sharpness": 0,
                "transform": "Normal",
                "uuid": "6277efe8-b61e-4335-b4d0-17cf1d8a536f",
                "vrrPolicy": "Never",
                "wideColorGamut": false
            },

And the output of kscreen-doctor --outputs showing VRR as “incapable”:

mmg@ultramarine ~
❯ kscreen-doctor --outputs
Output: 1 DP-2 6277efe8-b61e-4335-b4d0-17cf1d8a536f
enabled
connected
priority 1
DisplayPort
replication source:0
Modes: 1:2560x1440@60.00! 2:3840x2160@60.00 3:3840x2160@59.94 4:2560x1440@144.00* 5:2560x1440@120.00 6:1920x1080@120.00 7:1920x1080@119.88 8:1920x1080@74.98 9:1920x1080@60.00 10:1920x1080@59.94 11:1920x1080@60.00 12:1920x1080@50.00 13:1680x1050@119.95 14:1680x1050@59.95 15:1280x1024@119.96 1
6:1280x1024@75.03 17:1280x1024@60.02 18:1440x900@119.98 19:1440x900@59.89 20:1280x720@60.00 21:1280x720@59.94 22:1024x768@75.03 23:1024x768@60.00 24:800x600@75.00 25:800x600@60.32 26:720x576@50.00 27:720x480@60.00 28:720x480@59.94 29:640x480@75.00 30:640x480@60.00 31:640x480@59.94 32:640x480@59.94
33:720x400@70.08
Custom modes: None
Geometry: 0,0 2560x1440
Scale: 1
Rotation: 1
Overscan: 0
Vrr: incapable
RgbRange: Full
HDR: incapable
Wide Color Gamut: incapable
ICC profile: none
Color profile source: sRGB
Color power preference: prefer efficiency and performance
Brightness control: supported, set to 80% and dimming to 100%
DDC/CI: allowed
Color resolution: 10 bits per color, range: [6; 12] bits per color
Allow EDR: unsupported
Sharpness control: unsupported
Automatic brightness: unsupported
Auto Rotate Policy: incapable
Adaptive backlight modulation: unsupported

I was initially under the assumption that this was the only reasonable possibility for what caused the blackouts, but I am not very good at this. Any help with next steps would be appreciated. Thanks!