SUMMARY On my OLED screen I use as much black as possible (wallpaper, dark mode). With kwin-6.3.3 I noticed that in SDR mode my "solid color: black" wallpaper appears to have a faint gray. Switching to HDR mode has proper true black again. This is with no ICC profile configured and "Prefer efficiency" set. Though toying with either didn't appear to change anything. Reminds me of a https://bugs.kde.org/show_bug.cgi?id=494854 - except likely no vk_hdr_layer involved. STEPS TO REPRODUCE 1. Own an OLED 2. Display black in SDR mode 3. Turn down external light sources in your room OBSERVED RESULT See the whole screen faintly glowing EXPECTED RESULT Only the mouse cursor should emit light SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 6.3.3 KDE Frameworks Version: 6.12.0 Qt Version: 6.8.2 Kernel Version: 6.13.6-arch1-1 (64-bit) Graphics Platform: Wayland Processors: 16 × AMD Ryzen 7 PRO 4750U with Radeon Graphics Memory: 46.3 GiB of RAM Graphics Processor: AMD Radeon Graphics
Can't replicate that on my LCD's backlight dimming, though the brightness levels they turn on might be different from OLED. Please attach the output of kscreen-doctor -o
(In reply to Zamundaaa from comment #1) > Can't replicate that on my LCD's backlight dimming, though the brightness > levels they turn on might be different from OLED. > > Please attach the output of kscreen-doctor -o SDR: Output: 4 HDMI-A-1 enabled connected priority 1 HDMI Modes: 91:3840x2160@60*! 92:4096x2160@120 93:4096x2160@120 94:4096x2160@100 95:4096x2160@60 96:4096x2160@60 97:4096x2160@50 98:4096x2160@30 99:4096x2160@30 100:4096x2160@25 101:4096x2160@24 102:4096x2160@24 103:3840x2160@120 104:3840x2160@120 105:3840x2160@100 106:3840x2160@60 107:3840x2160@60 108:3840x2160@50 109:3840x2160@30 110:3840x2160@30 111:3840x2160@25 112:3840x2160@24 113:3840x2160@24 114:2560x1440@120 115:1920x1200@60 116:1920x1080@120 117:1920x1080@120 118:1920x1080@100 119:1920x1080@60 120:1920x1080@60 121:1920x1080@60 122:1920x1080@50 123:1920x1080@30 124:1920x1080@30 125:1920x1080@25 126:1920x1080@24 127:1920x1080@24 128:1600x1200@60 129:1680x1050@60 130:1280x1024@60 131:1440x900@60 132:1280x800@60 133:1152x864@60 134:1280x720@60 135:1280x720@60 136:1280x720@50 137:1024x768@60 138:800x600@60 139:720x576@50 140:720x480@60 141:720x480@60 142:720x480@60 143:720x480@60 144:640x480@60 145:640x480@60 146:720x400@70 147:1600x1200@60 148:1280x1024@60 149:1024x768@60 150:2560x1600@60 151:1920x1200@60 152:1280x800@60 153:3840x2160@60 154:3200x1800@60 155:2880x1620@60 156:2560x1440@60 157:1920x1080@60 158:1600x900@60 159:1368x768@60 160:1280x720@60 Geometry: 0,0 3840x2160 Scale: 1 Rotation: 1 Overscan: 0 Vrr: Always RgbRange: unknown HDR: disabled Wide Color Gamut: disabled ICC profile: none Color profile source: sRGB Color power preference: prefer efficiency and performance Brightness control: supported, set to 100% and dimming to 100% HDR: Output: 4 HDMI-A-1 enabled connected priority 1 HDMI Modes: 91:3840x2160@60*! 92:4096x2160@120 93:4096x2160@120 94:4096x2160@100 95:4096x2160@60 96:4096x2160@60 97:4096x2160@50 98:4096x2160@30 99:4096x2160@30 100:4096x2160@25 101:4096x2160@24 102:4096x2160@24 103:3840x2160@120 104:3840x2160@120 105:3840x2160@100 106:3840x2160@60 107:3840x2160@60 108:3840x2160@50 109:3840x2160@30 110:3840x2160@30 111:3840x2160@25 112:3840x2160@24 113:3840x2160@24 114:2560x1440@120 115:1920x1200@60 116:1920x1080@120 117:1920x1080@120 118:1920x1080@100 119:1920x1080@60 120:1920x1080@60 121:1920x1080@60 122:1920x1080@50 123:1920x1080@30 124:1920x1080@30 125:1920x1080@25 126:1920x1080@24 127:1920x1080@24 128:1600x1200@60 129:1680x1050@60 130:1280x1024@60 131:1440x900@60 132:1280x800@60 133:1152x864@60 134:1280x720@60 135:1280x720@60 136:1280x720@50 137:1024x768@60 138:800x600@60 139:720x576@50 140:720x480@60 141:720x480@60 142:720x480@60 143:720x480@60 144:640x480@60 145:640x480@60 146:720x400@70 147:1600x1200@60 148:1280x1024@60 149:1024x768@60 150:2560x1600@60 151:1920x1200@60 152:1280x800@60 153:3840x2160@60 154:3200x1800@60 155:2880x1620@60 156:2560x1440@60 157:1920x1080@60 158:1600x900@60 159:1368x768@60 160:1280x720@60 Geometry: 0,0 3840x2160 Scale: 1 Rotation: 1 Overscan: 0 Vrr: Always RgbRange: unknown HDR: enabled SDR brightness: 150 nits SDR gamut wideness: 0% Peak brightness: unknown Max average brightness: unknown Min brightness: 0 nits Wide Color Gamut: enabled ICC profile: none Color profile source: sRGB Color power preference: prefer efficiency and performance Brightness control: supported, set to 100% and dimming to 100% It's really faint, almost unnoticeable - much lower luminance iirc than with 494854.