499034 2025-01-23 02:57:09 +0000 New account on Wayland session with Display Port sets monitor brightness to 100% rather than reading hardware brightness level 2025-01-27 21:19:54 +0000 1 1 4 Plasma plasmashell Power management & brightness 6.2.5 Other Linux RESOLVED DUPLICATE 494408 https://bugs.kde.org/show_bug.cgi?id=499035 NOR normal 1.0 0 amdfan12 plasma-bugs-null jgqehj55 jpetso nate xaver.hugl 0 oldest_to_newest 2391811 0 amdfan12 2025-01-23 02:57:09 +0000 SUMMARY - Creating a new account on KDE and using the Wayland session will result in your monitor's brightness being set to 100%, not respecting the monitor's existing brightness setting. The problem doesn't seem to exist on the X11 session. I first noticed this with OpenSUSE, which uses X11 by default. In the X11 session, my monitors' brightness level remained at their initial values. When I tried switching to the Wayland session, both monitors immediately were set to 100% brightness. A fresh install of Fedora KDE Edition also resulted in the same behavior. Fedora KDE uses Wayland by default, and upon first login, both monitors were immediately set to 100% brightness. Once you set your brightness to the desired level, it remembers it. However creating a new account will result in 100% brightness again. STEPS TO REPRODUCE 1. Create new account on KDE 2. Log into new account using Wayland with a Display Port monitor OBSERVED RESULT Monitor's brightness will automatically get set to 100%, regardless of what the prior brightness setting was. EXPECTED RESULT Monitor's brightness should remain what its original value was SOFTWARE/OS VERSIONS Linux/KDE Plasma: Fedora 41/OpenSUSE Tumbleweed KDE Plasma Version: 6.2.5 KDE Frameworks Version: 6.10.0 Qt Version: 6.8.1 ADDITIONAL INFORMATION Pixio PX275h monitors connected via Display Port Radeon 5700XT 2392026 1 nate 2025-01-23 15:56:40 +0000 Same deal as Bug 499035; it's intentional that brightness is a subjective user preference and not a systemwide thing, so it doesn't make sense to inherit a different user's brightness setting in a new user account. 2392177 2 amdfan12 2025-01-24 00:48:10 +0000 (In reply to Nate Graham from comment #1) > Same deal as Bug 499035; it's intentional that brightness is a subjective > user preference and not a systemwide thing, so it doesn't make sense to > inherit a different user's brightness setting in a new user account. Hi Nate, I will agree with you if you were talking about a mobile situation, like a tablet or a laptop where brightness is expected to change. But this is a desktop situation, and I will STRONGLY disagree that it's ever appropriate to override the ***hardware's settings*** in a desktop environment. Desktop users typically have much less variable ambient lighting, and will spend time adjusting or calibrating their monitors to a preferred level and leave them be. It is a big problem that KDE is *making changes to my hardware settings* without asking my permission/consent to do so. I spent a lot of time calibrating and adjusting my monitors to how I liked them, and KDE Wayland blew my calibration away by adjusting the brightness without asking. If it weren't for the fact I had the brightness value written down, I would have been out of luck. This is very much a bug, since no other modern operating system overrides brightness levels like that: - Windows does not override my monitor's set hardware brightness level on new install, or account creation - The latest edition of Ubuntu (running Wayland) does not override my monitor's set hardware brightness level on new install, or account creation. - The latest edition of Linux Mint does not override my monitor's brightness level on new install or account creation To add some additional perspective: It costs money to have monitors professional calibrated. It can be anywhere from $500/monitor or more in a professional setting to have someone come out and professionally calibrate and certify your monitor. If a production studio (photography, video, whatever) gets, 10 workstations, calibrates them, and then hires 10 people to use them - KDE would cost them $5,000 in blown calibrations the moment they create user accounts for those employees. This is *wrong* behavior. The OS should never change my *hardware settings* on a desktop machine without asking. Ever. No other OS or desktop environment does this. 2392705 3 2wxsy58236r3 2025-01-26 15:04:21 +0000 Maybe try disabling DDC/CI in your monitor's setting (I suppose professional monitors are more likely to have this setting) as a workaround? 2392737 4 nate 2025-01-26 18:13:29 +0000 I agree we shouldn't override the hardware's *default* brightness setting. But is that actually what we're doing? In other words, if you have a monitor that's set to 25% brightness by default the first time you plug it in, and you change it to 50% in your current user account, and then you create a new user account, is it getting set to 100% in the new user account? Or 50%? 2392739 5 amdfan12 2025-01-26 18:30:11 +0000 (In reply to Nate Graham from comment #4) > I agree we shouldn't override the hardware's *default* brightness setting. > But is that actually what we're doing? > > In other words, if you have a monitor that's set to 25% brightness by > default the first time you plug it in, and you change it to 50% in your > current user account, and then you create a new user account, is it getting > set to 100% in the new user account? Or 50%? Here's an example: - Through my monitor's built in controls and on-screen-display, I manually set the monitor's brightness to 30% - If I boot into Windows, Ubuntu or KDE X11, the monitor's brightness remains at 30%. KDE X11 will even acknowledge the monitor's brightness being 30% in the brightness tray icon - Creating and then logging into a new account on Windows, Ubuntu, or KDE X11 will respect the 30% brightness level the monitor already has set. - A fresh install of an OS with KDE Wayland will *not* respect the monitor's already existing hardware brightness level. First log-in on Fedora KDE or Tumbleweed with a KDE Wayland will force the monitor to 100% brightness. If I manually go into my monitor, and reset the brightness to 30%, or set the brightness to 30% using the tray slider, it will remember it. - If I create a new account and log in to that new account, or re-install the OS, it will override my brightness settings back to 100%, even though I already turned them back to 30% prior. 2393032 6 nate 2025-01-27 21:02:34 +0000 Ok yeah, those do seem like bugs, or undesirable features (if considered intentional). I wonder if it might be hardware-specific, though. On my system, if I set the brightness to 50% (a value of 128 in `/sys/class/backlight/*/brightness`) and log into a newly created user account, the brightness is at 50%/128; the value was not changed to 100% as you're seeing. 2393036 7 jpetso 2025-01-27 21:14:45 +0000 We fixed this for 6.3.0, Plasma on Wayland (i.e. KWin+PowerDevil) will now read and adopt the brightness level of a display that hasn't been seen before. It will still ignore any subsequent changes through the monitor's OSD menu, but that's a different issue we'll have to resolve later. *** This bug has been marked as a duplicate of bug 494408 *** 2393039 8 nate 2025-01-27 21:19:54 +0000 Aha, no wonder I couldn't reproduce it on master!