Bug 505857

Summary: HDR desaturation issues with after updating to 6.4 from 6.3.5
Product: [Plasma] kwin Reporter: pvpdmail
Component: colour-managementAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED FIXED    
Severity: major CC: avery-j, kde, kdedev, nate, xaver.hugl
Priority: NOR Keywords: regression
Version First Reported In: 6.4.0   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: 6.3.5 kscreen-doctor -o at 0% sRGB intensity
6.3.5 kscreen-doctor -o at 100% sRGB intensity
6.4.2 kscreen-doctor -o at 0% sRGB intensity
6.4.2 kscreen-doctor -o at 100% sRGB intensity
6.3.5 image at 100% sRGB intensity
6.3.5 image at 0% sRGB intensity
6.4.2 image at 100% sRGB intensity
6.4.2 image at 0% sRGB intensity
6.3.5 drm_info at 0% sRGB intensity
6.3.5 drm_info at 100% sRGB intensity
6.4.2 drm_info at 0% sRGB intensity
6.4.2 drm_info at 100% sRGB intensity

Description pvpdmail 2025-06-20 16:08:50 UTC
SUMMARY
When I did a full system (Arch) update to Plasma 6.4 and after rebooting SDR content when using HDR for my monitor (AOC AG276QZD2) started looking washed out. I did the HDR calibration but to no avail. the sRGB color intensity slider had no effect (100% was exactly the same as 0%) while on 6.3.5 it had a pretty big one. Also, from what I could see, HDR content also looked quite worse, but I didn't confirm that. I reverted back to yesterday's (6.3.5) state (timeshift is magic when it works) and it's a night and day difference for SDR, I still didn't test HDR.

STEPS TO REPRODUCE
1. update to plasma 6.4 from 6.3.5

 RESULT
SDR (and possibly HDR) looks worse than 6.3.5 even after spending lots of time trying to calibrate and fix it.

EXPECTED RESULT
HDR looks better with all the new tools in the settings.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.3.5
KDE Frameworks Version: 6.15.0
Qt Version: 6.9.1
Kernel Version: 6.15.2-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 3700X 8-Core Processor
Memory: 15.5 GiB of RAM
Graphics Processor: AMD Radeon RX 6700 XT
 

ADDITIONAL INFORMATION
Monitor is AOC AG276QZD2. I can attach even more info if it is needed, though, I'd prefer if I didn't have to go back and forth on plasma versions. Also, this might not be an issue of kscreen, but it seemed like the most sensible thing to pin it on. Here is the list of all packages that were upgraded when going from 6.3.5 to 6.4: 

abseil-cpp-20250512.1-1  aurorae-6.4.0-1  bluedevil-1:6.4.0-1  breeze-6.4.0-1  breeze-gtk-6.4.0-1 discover-6.4.0-1
docker-buildx-0.25.0-1  drkonqi-6.4.0-1  freerdp-2:3.15.0-1  fwupd-2.0.12-1  gocryptfs-2.5.4-1  kactivitymanagerd-6.4.0-1 kde-cli-tools-6.4.0-1  kde-gtk-config-6.4.0-1  kdecoration-6.4.0-1  kdeplasma-addons-6.4.0-1  kgamma-6.4.0-1 kglobalacceld-6.4.0-1  kinfocenter-6.4.0-1  kmenuedit-6.4.0-1  kpipewire-6.4.0-1  krdp-6.4.0-1  kscreen-6.4.0-1 kscreenlocker-6.4.0-1  ksshaskpass-6.4.0-1  kwallet-pam-6.4.0-1  kwayland-6.4.0-1  kwin-6.4.0-1  kwrited-6.4.0-1 layer-shell-qt-6.4.0-1  lib32-mesa-1:25.1.4-1  libkscreen-6.4.0-1  libksysguard-6.4.0-1  libplasma-6.4.0-1  libxnvctrl-575.64-1 mesa-1:25.1.4-1  milou-6.4.0-1  ocean-sound-theme-6.4.0-1 oxygen-6.4.0-1  oxygen-sounds-6.4.0-1  plasma-activities-6.4.0-1 plasma-activities-stats-6.4.0-1  plasma-browser-integration-6.4.0-1  plasma-desktop-6.4.0-1  plasma-disks-6.4.0-1 plasma-firewall-6.4.0-1  plasma-integration-6.4.0-1  plasma-meta-6.4-4  plasma-nm-6.4.0-1  plasma-pa-6.4.0-1 plasma-systemmonitor-6.4.0-1  plasma-thunderbolt-6.4.0-1  plasma-vault-6.4.0-2  plasma-welcome-6.4.0-1  plasma-workspace-6.4.0-4 plasma-workspace-wallpapers-6.4.0-1  plasma5support-6.4.0-1  polkit-kde-agent-6.4.0-1  powerdevil-6.4.0-1 print-manager-1:6.4.0-1  qqc2-breeze-style-6.4.0-1  qt6-location-6.9.1-1  sddm-kcm-6.4.0-1  sdl2_ttf-2.24.0-1 spectacle-1:6.4.0-1  systemsettings-6.4.0-1  vulkan-intel-1:25.1.4-1  vulkan-radeon-1:25.1.4-1 wacomtablet-6.4.0-1 xdg-desktop-portal-kde-6.4.0-1
Comment 1 Avery J. 2025-06-21 04:59:43 UTC
I am also having this issue with a GSM LG ULTRA monitor on Arch as well.
Comment 2 lakmoesproef 2025-06-21 08:23:05 UTC
Same problem here: washed out colors since plasma 6.4. Persist regardless of connection (DP v1.4 & DP v1.4 over Thunderbolt; same for v1.2) and GPU (AMD Radeon 780M & AMD Radeon 9700 XT)

$ ddcutil detect
Display 1
   I2C bus:  /dev/i2c-13
   DRM_connector:           card0-DP-5
   EDID synopsis:
      Mfg id:               GSM - Goldstar Company Ltd (LG)
      Model:                LG ULTRAWIDE
      Product code:         40577  (0x9e81)
      Serial number:        201NTSU1H406
      Binary serial number: 51406 (0x0000c8ce)
      Manufacture year:     2022,  Week: 1
   VCP version:         2.1
Comment 3 TraceyC 2025-06-24 22:00:15 UTC
I don't see this on git-master with an NVIDIA GPU. 
Hopefully someone with an AMD GPU can test this on git-master
Comment 4 TraceyC 2025-06-25 01:34:34 UTC
Can one of you who is seeing this bug please share a screenshot of washed out SDR content with some HDR content to highlight the difference for folks who may not know what to look for? Thanks
Comment 5 Avery J. 2025-06-26 06:03:04 UTC
(In reply to TraceyC from comment #4)
> Can one of you who is seeing this bug please share a screenshot of washed
> out SDR content with some HDR content to highlight the difference for folks
> who may not know what to look for? Thanks
I tried taking screenshots with HDR enabled and disabled but they hardly look any different. It doesn't match what I see in person. I forgot to mention I'm using a NVIDIA RTX 4070 SUPER. It would seem both AMD and NVIDIA users are having the same issue.
Comment 6 TraceyC 2025-06-26 17:04:55 UTC
(In reply to Avery J. from comment #5)
> I tried taking screenshots with HDR enabled and disabled but they hardly
> look any different. It doesn't match what I see in person. I forgot to
> mention I'm using a NVIDIA RTX 4070 SUPER. It would seem both AMD and NVIDIA
> users are having the same issue.

Thanks for the additional information.

Can anyone who is affected take a picture of their monitor with a phone or another camera that shows the problem? Thanks.
Comment 7 Zamundaaa 2025-06-27 14:17:23 UTC
Just to be sure, if you disable DDC/CI, then disable HDR and enable it again, does that make a difference?

Also, please attach the output of kscreen-doctor -o and drm_info (as files). Ideally for both 6.3.5 and 6.4
Comment 8 pvpdmail 2025-07-03 23:25:51 UTC
Created attachment 182915 [details]
6.3.5 kscreen-doctor -o at 0% sRGB intensity
Comment 9 pvpdmail 2025-07-03 23:26:47 UTC
Created attachment 182916 [details]
6.3.5 kscreen-doctor -o at 100% sRGB intensity
Comment 10 pvpdmail 2025-07-03 23:27:17 UTC
Created attachment 182917 [details]
6.4.2 kscreen-doctor -o at 0% sRGB intensity
Comment 11 pvpdmail 2025-07-03 23:27:37 UTC
Created attachment 182918 [details]
6.4.2 kscreen-doctor -o at 100% sRGB intensity
Comment 12 pvpdmail 2025-07-03 23:29:15 UTC
Created attachment 182919 [details]
6.3.5 image at 100% sRGB intensity
Comment 13 pvpdmail 2025-07-03 23:32:46 UTC
Created attachment 182920 [details]
6.3.5 image at 0% sRGB intensity
Comment 14 pvpdmail 2025-07-03 23:33:44 UTC
Created attachment 182921 [details]
6.4.2 image at 100% sRGB intensity
Comment 15 pvpdmail 2025-07-03 23:34:06 UTC
Created attachment 182922 [details]
6.4.2 image at 0% sRGB intensity
Comment 16 pvpdmail 2025-07-03 23:41:20 UTC
Here is both kscreen-doctor -o from 6.3.5 and 6.4.2 at both 0% and 100% sRGB intensity and some sample images of the difference. Personally, I lost track of which 6.4.2 image was at which intensity as they are exactly the same. For 6.3.5 you should probably look at the blue bar of "Display & Monitor" where the effect shows up best on camera. It goes without saying that the effect is a lot more noticeable in person than in camera (I had to put the white remote there just to try and have a constant white balance). I couldn't provide the drm_info as I didn't have it installed.

On another note, I had a slight suspicion that having the sRGB intensity slider at 0% when updating and then increasing it might fix the issue, but no. Also, disabling HDR, DDC/CI and turning the monitor off and on again didn't help with the issue. 

It feels bad to have to revert back to 6.3.5 due to the HDR bug when 6.4.2 is so good :(
Comment 17 Zamundaaa 2025-07-04 14:12:12 UTC
The color intensity slider not working most likely has the same cause as bug 505971, and should be fixed in 6.4.3. The output of drm_info would allow me to make sure of that.
If your display clips colors to the HDR metadata we provide, then the same fix might also help with this problem.

If you want to test it before the release of 6.4.3, you could compile the Plasma/6.4 branch of KWin yourself, or by adding only https://invent.kde.org/plasma/kwin/-/commit/cd4f1ebd3d316de965bdb303121639b3a90a4fdb to the PKGBUILD of the current kwin package and rebuilding that.
Comment 18 pvpdmail 2025-07-04 14:31:01 UTC
Created attachment 182951 [details]
6.3.5 drm_info at 0% sRGB intensity
Comment 19 pvpdmail 2025-07-04 14:31:16 UTC
Created attachment 182952 [details]
6.3.5 drm_info at 100% sRGB intensity
Comment 20 pvpdmail 2025-07-04 14:54:38 UTC
Created attachment 182953 [details]
6.4.2 drm_info at 0% sRGB intensity
Comment 21 pvpdmail 2025-07-04 14:55:00 UTC
Created attachment 182954 [details]
6.4.2 drm_info at 100% sRGB intensity
Comment 22 pvpdmail 2025-07-04 14:55:28 UTC
Hope these are fine.
Comment 23 Zamundaaa 2025-07-04 15:21:44 UTC
Good, that's exactly the same as in bug 505971:
> │   │       │   ├───Display primaries:
> │   │       │   │   ├───Red: (0.6400, 0.3300)
> │   │       │   │   ├───Green: (0.3000, 0.6000)
> │   │       │   │   └───Blue: (0.1500, 0.0600)
> │   │       │   ├───White point: (0.3127, 0.3290)

Let's wait for 6.4.3 then before doing any more digging. It's almost certainly gonna be fixed there :)
Comment 24 pvpdmail 2025-07-16 12:29:21 UTC
Update 6.4.3 seems to have fixed this issue for me. Colors now look just as good (maybe even better due to the calibration) as in previous versions.