SUMMARY I get a black screen when enabling HDR for my Samsung Q80T TV. It works fine if TV Game Mode is On (but I keep it Off for watching movies since I have better HDR brightness outside of Game Mode). With TV Game Mode Off, I had no issue with plasma 6.3, and have no issue with Windows 11 and Gnome 48. TV is connected on HDMI 2.1 port, NVIDIA card (RTX 4080). STEPS TO REPRODUCE 1. TV Game Mode is Off (Samsung Q80T TV) 2. Turn HDR on in Plasma 6.4 ticking HDR box in Display Settings 3. Apply OBSERVED RESULT Black screen EXPECTED RESULT HDR turned On SOFTWARE/OS VERSIONS Operating System: CachyOS Linux (Arch based) KDE Plasma Version: 6.4.0 KDE Frameworks Version: 6.15.0 Qt Version: 6.9.1 Kernel Version: 6.15.3-2-cachyos (64-bit) Graphics Platform: Wayland Processors: 8 × Intel® Core™ i7-9700K CPU @ 3.60GHz Memory: 32 Gio of RAM (31.3 Gio usable) Graphics Processor: NVIDIA GeForce RTX 4080
Please attach the output of > drm_info > kscreen-doctor -o and > cat /sys/class/drm/card1-HDMI-A-1/edid > edid.bin (connector name may need adjusting), once for when game mode is on, and once for when it's off. If you don't have a second screen and need to run it through ssh, you can prepend WAYLAND_DISPLAY=wayland-0 before kscreen-doctor to make it work.
(In reply to Zamundaaa from comment #1) > Please attach the output of > > drm_info > > kscreen-doctor -o > and > > cat /sys/class/drm/card1-HDMI-A-1/edid > edid.bin > (connector name may need adjusting), once for when game mode is on, and once > for when it's off. > > If you don't have a second screen and need to run it through ssh, you can > prepend WAYLAND_DISPLAY=wayland-0 before kscreen-doctor to make it work. For game mode off, I assume that's without enabling HDR in plasma (since I can't), but what about game mode on ? Do you want these outputs with or without HDR enabled ?
No, I need it with HDR on in both cases.
Created attachment 182729 [details] drm_info tv game mode off
Created attachment 182730 [details] kscreen-doctor -o tv game mode off
Created attachment 182731 [details] edid.bin tv game mode off
Created attachment 182732 [details] drm_info tv game mode on
Created attachment 182733 [details] kscreen doctor -o tv game mode on
Created attachment 182734 [details] edid.bin tv game mode on
(In reply to Zamundaaa from comment #3) > No, I need it with HDR on in both cases. Done. Thanks for looking at it.
A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin/-/merge_requests/7838
Don't know how you managed to set the peak brightness override to zero, but that looks to be the problem, and the MR will guard against it. Until that's in, deleting the "maxPeakBrightnessOverride": 0 line from ~/.config/kwinoutputconfig.json should fix it. Note that KWin saves its cached config when quitting, so you'll need to either edit the file while not logged in, or kill kwin with "killall -9 kwin_wayland" after making the change
Git commit a98fa02d91b40aeb7c7a5253625d93fb1ee705b2 by Xaver Hugl. Committed on 27/06/2025 at 16:02. Pushed by zamundaaa into branch 'master'. output management: add some safe guards for invalid brightness overrides Apparently it's somehow possible to set a max peak brightness override of zero, which makes it impossible to display anything. M +8 -0 src/outputconfigurationstore.cpp M +8 -0 src/wayland/outputmanagement_v2.cpp https://invent.kde.org/plasma/kwin/-/commit/a98fa02d91b40aeb7c7a5253625d93fb1ee705b2
(In reply to Zamundaaa from comment #12) > Don't know how you managed to set the peak brightness override to zero, but > that looks to be the problem, and the MR will guard against it. > > Until that's in, deleting the > "maxPeakBrightnessOverride": 0 > line from ~/.config/kwinoutputconfig.json should fix it. > > Note that KWin saves its cached config when quitting, so you'll need to > either edit the file while not logged in, or kill kwin with "killall -9 > kwin_wayland" after making the change That did the trick, thank you. No idea on how it happens though. It was fine before I update to plasma 6.4 (from 6.3.5), and I had the issue immediately after.
Git commit a5515e1396fb0b459cab7416dbe70e91757f6f0b by Xaver Hugl, on behalf of Xaver Hugl. Committed on 27/06/2025 at 20:50. Pushed by zamundaaa into branch 'Plasma/6.4'. output management: add some safe guards for invalid brightness overrides Apparently it's somehow possible to set a max peak brightness override of zero, which makes it impossible to display anything. (cherry picked from commit a98fa02d91b40aeb7c7a5253625d93fb1ee705b2) Co-authored-by: Xaver Hugl <xaver.hugl@kde.org> M +8 -0 src/outputconfigurationstore.cpp M +8 -0 src/wayland/outputmanagement_v2.cpp https://invent.kde.org/plasma/kwin/-/commit/a5515e1396fb0b459cab7416dbe70e91757f6f0b
Git commit 7fc87b91dbc69bd9935211589ba3c84717269d58 by Xaver Hugl, on behalf of Xaver Hugl. Committed on 27/06/2025 at 20:50. Pushed by zamundaaa into branch 'Plasma/6.3'. output management: add some safe guards for invalid brightness overrides Apparently it's somehow possible to set a max peak brightness override of zero, which makes it impossible to display anything. (cherry picked from commit a98fa02d91b40aeb7c7a5253625d93fb1ee705b2) Co-authored-by: Xaver Hugl <xaver.hugl@kde.org> M +8 -0 src/outputconfigurationstore.cpp M +8 -0 src/wayland/outputmanagement_v2.cpp https://invent.kde.org/plasma/kwin/-/commit/7fc87b91dbc69bd9935211589ba3c84717269d58