SUMMARY When pressing the brightness up or down keys, the brightness changes by 10% instead of 5% most of the time. Sometimes, it changes by 5% but there doesn't seem to be a pattern to when it decides to correctly change by 5 instead of incorrectly changing by 10. Changing the shortcut to something without the brightness keys (like Meta+Shift+U or Meta+Shift+D) will not exhibit this behavior. Any shortcut that *does* use the brightness keys (like Ctrl+Monitor Brightness Up or Ctrl+Monitor Brightness Down) *will* exhibit this behavior. STEPS TO REPRODUCE 1. Press the brightness up or brightness down key OBSERVED RESULT The OSD will pop up and indicate a change of 10% instead of 5% most of the time. Sometimes it correctly changes by 5 but that seems to happen randomly. EXPECTED RESULT The brightness should consistently change by 5%. SOFTWARE/OS VERSIONS Linux: Arch Linux x86_64, Kernel 6.12.4-arch1-1 KDE Plasma Version: 6.2.4 KDE Frameworks Version: 6.9.0 Qt Version: 6.8.1 ADDITIONAL INFORMATION Machine (laptop): Dell Inspiron 15 3525 (0B6B) I couldn't get much info about the display itself other than it's a 120Hz 1920x1080 panel made by BOE.
Update: It seems to go after I put the machine to sleep and wake it up? I don't really know what could be causing this.
There have been a lot of improvements and bug fixes to brightness control since this report was opened. I'm not currently able to reproduce this on Plasma 6.3.2 or git-master. If this is still happening on your system, can you please copy and paste the output of `kscreen-doctor -o`? Thanks.
Hi, it's still happening and still goes away after I put the laptop into sleep and wake it up. Here's the output of 'kscreen-doctor -o' (I currently have the brightness set to 5% (I typically do around 5 to 15%) which I obtained by fiddling around with the brightness up/down keys until one of them changed by the correct 5% instead of the incorrect 10%): Output: 1 eDP-1 enabled connected priority 1 Panel Modes: 1:1920x1080@120*! 10:640x480@120 11:1280x1024@60 12:1024x768@60 13:1280x800@60 14:1920x1080@60 15:1600x900@60 16:1368x768@60 17:1280x720@60 2:1920x1080@60 3:1680x1050@120 4:1280x1024@120 5:1440x900@120 6:1280x800@120 7:1280x720@120 8:1024x768@120 9:800x600@120 Geometry: 0,0 1920x1080 Scale: 1 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 5% and dimming to 100%
Can I ask you to check if this is still happening with Plasma 6.3.5 or later? Thanks a lot!
Sorry for the late reply, I just upgraded and am now on version 6.3.5. The issue is still present.
Ok, thanks for the info.
Hi - just to check, are you able to see, using one of the tools at https://wiki.archlinux.org/title/Keyboard_input , if the Brightness Up/Brightness Down key is perhaps being sent twice by your keyboard when the 10% change is happening? Could you also confirm which graphics card you have present - it looks like that Dell model came configured with either AMD only, or AMD+NVIDIA graphics? Thanks!
OK I guess this is what the problem was. I installed evtest and went through all the event* devices in /dev/input. Two devices were sending brightness keys at the same time. - The 'event2' device which is the keyboard always sends the brightness key events. - The 'event8' device which is named "Dell WMI hotkeys" never sends brightness key events for some reason. - The 'event3' device which is named "Video Bus" and seems to be the problem will send brightness key events until I put the laptop to sleep. After I wake the laptop, it will no longer send brightness key events. So the keyboard (event2) and video bus (event3) both send brightness key events until I put the laptop to sleep. Once I wake the laptop, the video bus (event3) device no longer sends brightness key events. On top of that, there appears to be another device (event8) that looks like it *can* send brightness key events but seemingly never does. And to verify, I have the AMD-only model. It has the AMD integrated graphics and that's it; no NVIDIA. ---------------------------------------------------------------------- /dev/input/event2 (responding to brightness keys both before and after sleep): Input driver version is 1.0.1 Input device ID: bus 0x11 vendor 0x1 product 0x1 version 0xab83 Input device name: "AT Translated Set 2 keyboard" Supported events: Event type 0 (EV_SYN) Event type 1 (EV_KEY) ... Event code 224 (KEY_BRIGHTNESSDOWN) Event code 225 (KEY_BRIGHTNESSUP) ... ---------------------------------------------------------------------- /dev/input/event3 (responding to brightness keys before sleep, NOT responding to brightness keys after sleep): Input driver version is 1.0.1 Input device ID: bus 0x19 vendor 0x0 product 0x6 version 0x0 Input device name: "Video Bus" Supported events: Event type 0 (EV_SYN) Event type 1 (EV_KEY) Event code 224 (KEY_BRIGHTNESSDOWN) Event code 225 (KEY_BRIGHTNESSUP) ... ---------------------------------------------------------------------- /dev/input/event8 (NOT responding to brightness keys both before and after sleep): Input driver version is 1.0.1 Input device ID: bus 0x19 vendor 0x0 product 0x0 version 0x0 Input device name: "Dell WMI hotkeys" Supported events: Event type 0 (EV_SYN) Event type 1 (EV_KEY) ... Event code 224 (KEY_BRIGHTNESSDOWN) Event code 225 (KEY_BRIGHTNESSUP) ...
Thanks! Resolving the presence of duplicate devices showing up and both sending keystrokes would be upstream of what KDE controls in the Linux software stack, but some possibly relevant links are below - hopefully there's something that can help narrow down how to work around that quirk in your device's hardware, or resolve a potential kernel issue. https://lkml.org/lkml/2022/7/19/876 https://bugzilla.kernel.org/show_bug.cgi?id=9614 https://bugzilla.kernel.org/show_bug.cgi?id=204077
Alright, thanks