Created attachment 183584 [details] stuck at 50% SUMMARY After updating to 6.4, setting brightness to 0% is like 8%, increasing to 1% make it dimmer (actually what 0% should have looked like). STEPS TO REPRODUCE 1. set brightness to 0% OBSERVED RESULT 0% is very bright (like 8% brightness) than it is supposed to be. EXPECTED RESULT normal, 0% is very dim and gets bright when increasing the slider. SOFTWARE/OS VERSIONS Operating System: Fedora Linux 41 KDE Plasma Version: 6.4.3 KDE Frameworks Version: 6.16.0 Qt Version: 6.8.3 Kernel Version: 6.15.7-100.fc41.x86_64 (64-bit) Graphics Platform: Wayland ADDITIONAL INFORMATION Not sure if relevant, but I think the issue is with GPU, after updating (I was on 6.3.3), it worked normally, but I think I was using an integrated graphics (AMD), when I was checking "About this system" in settings, it didn't show the discrete GPU (Nvidia). Now it does show both. I also checked "System Monitor" and it is stuck on 50% whatever I do, and in "History" tab "GPU 2 usage" is 0% and GPU 3 usage is 100%" always.
Created attachment 183585 [details] "GPU 2 usage" is 0% and GPU 3 usage is 100%" always
Moving to the right category
I'm not able to reproduce this on git-master or Plasma 6.4.3, with laptops or external monitors Can you run the following command and paste the output into this report? kscreen-doctor -o Thanks!
(In reply to TraceyC from comment #3) > I'm not able to reproduce this on git-master or Plasma 6.4.3, with laptops > or external monitors > > Can you run the following command and paste the output into this report? > > kscreen-doctor -o > > Thanks! Output: 1 eDP-1 527ef525-8b69-4e0c-92c2-2047b9686be7 enabled connected priority 1 Panel replication source:0 Modes: 1:1920x1080@60*! 2:1920x1080@40 3:1680x1050@60 4:1280x1024@60 5:1440x900@60 6:1280x800@60 7:1280x720@60 8:1024x768@60 9:800x600@60 10:640x480@60 11:1600x900@60 12:1368x768@60 Geometry: 0,0 1536x864 Scale: 1.25 Rotation: 1 Overscan: 0 Vrr: Automatic RgbRange: unknown 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 4% and dimming to 100% Color resolution: automatic (10), range: [8; 16] bits per color Allow EDR: always Thanks for looking into it, really annoying to have to deal with it after expecting a better experience after updating :)
Thanks. I'll let the plasmashell folks take a closer look.
i have the same issue basically on my Hybrid dell where i see my IGPU is actually even disabled and Nvidia is always enabled ´´´ phatle@kinoite:/var/home/phatle$ kscreen-doctor -o Output: 1 eDP-1 80b8cc53-968d-458c-90df-ee8a161970ff disabled connected priority 0 Panel replication source:0 Modes: 1:3456x2160@60*! 2:1600x1200@60 3:1600x1200@60 4:1280x1024@60 5:1280x1024@60 6:1024x768@60 7:1024x768@60 8:2560x1600@60 9:2560x1600@60 10:1920x1200@60 11:1920x1200@60 12:1280x800@60 13:1280x800@60 14:3200x1800@60 15:3200x1800@60 16:2880x1620@60 17:2880x1620@60 18:2560x1440@60 19:2560x1440@60 20:1920x1080@60 21:1920x1080@60 22:1600x900@60 23:1600x900@60 24:1368x768@60 25:1368x768@60 26:1280x720@60 27:1280x720@60 Geometry: 0,0 2765x1728 Scale: 1.25 Rotation: 1 Overscan: 0 Vrr: incapable RgbRange: Automatic HDR: enabled SDR brightness: 400 nits SDR gamut wideness: 0% Peak brightness: 617 nits Max average brightness: 400 nits Min brightness: 0.0046 nits Wide Color Gamut: enabled ICC profile: none Color profile source: sRGB Color power preference: prefer accuracy Brightness control: supported, set to 6% and dimming to 100% Color resolution: automatic (16), range: [6; 12] bits per color Allow EDR: always Output: 2 DP-3 f404a99e-ead0-4fbe-9f3a-a5e7e926a041 enabled connected priority 1 DisplayPort replication source:0 Modes: 28:3440x1440@60*! 29:3440x1440@50 30:3440x1440@30 31:2560x1080@60 32:1920x1080@60 33:1920x1080@60 34:1920x1080@60 35:1920x1080@50 36:1680x1050@60 37:1600x900@60 38:1280x1024@60 39:1280x800@60 40:1152x864@60 41:1280x720@60 42:1280x720@60 43:1280x720@60 44:1280x720@50 45:1024x768@60 46:800x600@60 47:720x576@50 48:720x480@60 49:720x480@60 50:640x480@60 51:640x480@60 52:640x480@60 Geometry: 0,0 3440x1440 Scale: 1 Rotation: 1 Overscan: 0 Vrr: incapable RgbRange: Automatic HDR: enabled SDR brightness: 295 nits SDR gamut wideness: 0% Peak brightness: 344 nits Max average brightness: 295 nits Min brightness: 0.391 nits Wide Color Gamut: enabled ICC profile: none Color profile source: sRGB Color power preference: prefer accuracy Brightness control: supported, set to 100% and dimming to 100% DDC/CI: allowed Color resolution: automatic (16), range: [6; 12] bits per color Allow EDR: unsupported ´´´
I have : ``` KDE Plasma Version: 6.3.6 KDE Frameworks Version: 6.16.0 Qt Version: 6.9.1 Kernel Version: 6.15.7-1-MANJARO (64-bit) Graphics Platform: Wayland Processors: 8 × AMD Ryzen 5 3500U with Radeon Vega Mobile Gfx, iGPU-only ``` and I see the same issue. ``` kscreen-doctor -o Output: 1 eDP-1 enabled connected priority 1 Panel Modes: 1:1920x1080@60*! 2:1920x1080@48 3:1680x1050@60 4:1280x1024@60 5:1440x900@60 6:1280x800@60 7:1280x720@60 8:1024x768@60 9:800x600@60 10:640x480@60 11:1280x1024@60 12:1024x768@60 13:1280x800@60 14:1920x1080@60 15:1600x900@60 16:1368x768@60 17:1280x720@60 Geometry: 0,0 1536x864 Scale: 1.25 Rotation: 1 Overscan: 0 Vrr: incapable RgbRange: unknown 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 5% and dimming to 100%
One issue per bug report, please. Let's use this one to track the brightness issue, and then we'll see later if the GPU issue is related. Affected people, please dim the screen to the lowest brightness possible using the brightness slider, and then paste the output of running `cat /sys/class/backlight/*/brightness` in a terminal window. Thanks!
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> Affected people, please dim the screen to the lowest brightness possible 0% is 1, 1% is 615 and it is much dimmer than 0% now :p
Thanks for the responses. Marko, can you also dim the screen to the lowest brightness possible using the brightness slider, and then paste the output of running `cat /sys/class/backlight/*/brightness` in a terminal window? Thanks!
Created attachment 183956 [details] attachment-1897271-0.html here is the output ´ phatle@kinoite:/var/home/phatle$ cat /sys/class/backlight/*/brightness 400´ On 11/08/2025 19:51, TraceyC wrote: > https://bugs.kde.org/show_bug.cgi?id=507579 > TraceyC > [<kdedev@tlcnet.info>](mailto:kdedev@tlcnet.info) > changed: > > What |Removed |Added > ---------------------------------------------------------------------------- > Resolution|WAITINGFORINFO |--- > Status|NEEDSINFO |REPORTED > > --- Comment #11 from TraceyC > [<kdedev@tlcnet.info>](mailto:kdedev@tlcnet.info) > --- > Thanks for the responses. > > Marko, can you also dim the screen to the lowest brightness possible using the > brightness slider, and then paste the output of running `cat > /sys/class/backlight/*/brightness` in a terminal window? > > Thanks! > > -- > You are receiving this mail because: > You are on the CC list for the bug.
(In reply to karolbienkowski from comment #10) > > Affected people, please dim the screen to the lowest brightness possible > 0% is 1, > 1% is 615 and it is much dimmer than 0% now :p It seems that Plasma is doing the right thing here. If 616 is dimmer than 1, that doesn't make any sense and will end up being a GPU driver bug. Please report to the place where driver bugs are tracked for your GPU. Intel and AMD: https://docs.mesa3d.org/bugs.html NVIDIA: post it at https://forums.developer.nvidia.com/c/gpu-graphics/linux; run nvidia-bug-report.sh and attach the resulting file to the report.
I created an issue here https://gitlab.freedesktop.org/mesa/mesa/-/issues/13690, affected people, please engage with this issue too. btw, Nate Graham, have you seen if the other GPU issues related too? (see images attached). I also found my issue was reported here https://www.dedoimedo.com/computers/plasma-6-4-review.html when I was researching for fixes. I think 6.4 is great it is just this bug is very annoying :P
There are unfortunately zillions of GPU-specific issues. Modern GPUs provide tons of power, but they suck for reliability.
Please improve your mesa bug report, though. It doesn't report the actual bug, just links here. That doesn't work, and it'll be ignored by everyone. You have to actually report the bug in there, which is that the lowest backlight brightness level (1) is visibly brighter than higher levels. Screenshots or screen recordings would be helpful too/
The problem is idk what exactly to write, people already shared their findings here. I don't think screenshots will show anything, however videos by external device (like a phone recording the issue will be helpful).
I told you exactly what to write: that the lowest backlight brightness level (1) is visibly brighter than higher levels You need to write a real bug report that describes what you did, what you expected, what happened instead, and so on. A braindump of information or a link to somewhere else is just going to get the bug report ignored.