| Summary: | Brightness control sometimes missing for secondary screen | ||
|---|---|---|---|
| Product: | [Plasma] plasmashell | Reporter: | Steffen W. <steffen-winkler> |
| Component: | Power management & brightness | Assignee: | Plasma Bugs List <plasma-bugs-null> |
| Status: | REPORTED --- | ||
| Severity: | normal | CC: | jpetso, natalie_clarius, nate, pj.world |
| Priority: | NOR | Keywords: | multiscreen |
| Version First Reported In: | 6.4.2 | ||
| Target Milestone: | 1.0 | ||
| Platform: | Arch Linux | ||
| OS: | Linux | ||
| See Also: | https://bugs.kde.org/show_bug.cgi?id=482713 | ||
| Latest Commit: | Version Fixed In: | ||
| Sentry Crash Report: | |||
| Attachments: |
kscreen-doctor -o output that shows the secondary screen not being capable of brightness control
kscreen-doctor -o output that shows the secondary screen being capable of brightness control Screen has the slider back after deactiving brightness control |
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Created attachment 183028 [details]
kscreen-doctor -o output that shows the secondary screen being capable of brightness control
Almost forgot: This has been going on ever since the brightness control tray icon got introduced in Plasma 6.2. I just was never able to figure out why it sometimes works and sometimes doesn't - until now. While in a KDE session where the brightness control was recognized for the secondary screen, switching off the secondary screen and then switching it back on results in the brightness control not reappearing. Logging out of the session, then switching the screen on and then logging back in makes the brightness control appear again. What version of DDC do you have? If it's not 2.2.1 or later, it may have already been fixed upstream; see Bug 482713. If you do have 2.2.1 or later, it's not that. I currently have [steffen ~] ddcutil --version ddcutil 2.2.1 and after switching on the secondary screen mid-session the brightness control did not add a slider for the second screen, also kscreen-doctor -o still reports "Brightness control: unsupported" in this situation. Found something else out. For one, the only difference between the output of kscreen-doctor -o when the brightness control is there and when it isn't is the Brightness control line. Specifically the DDC/CI line stays on "allowed" in both cases. When I enter the KDE settings application and go into display settings everything looks the same, too. Changing the display active status, the resolution or refresh rate does not lead to the brightness control for the screen (re-)appearing. However, in both cases the "Brightness" checkbox is checked. Even when no brightness control is available in the applet for the screen. In this situation, when I uncheck the Brightness checkbox the brightness control becomes available, kscreen-doctor -o reports DDC/CI "unallowed" but "Brightness control: supported, set to 100% and dimming to 100%", changing the slider does change the brightness of the screen. I'm adding a screenshot that shows this, though the UI is in German. Sidenote: It'd be a nifty feature if, during a screenshot, the UI can temporarily be changed to a different language as long as it is installed on the system. Created attachment 183884 [details]
Screen has the slider back after deactiving brightness control
Would just like to confirm that this is still an issue Operating System: Arch Linux KDE Plasma Version: 6.4.4 KDE Frameworks Version: 6.17.0 Qt Version: 6.9.2 Kernel Version: 6.16.4-arch1-1 (64-bit) Graphics Platform: Wayland Still happening as of KDE Plasma Version: 6.4.5 KDE Frameworks Version: 6.18.0 Qt Version: 6.9.2 Kernel Version: 6.16.8-arch3-1 (64-bit) Graphics Platform: Wayland |
Created attachment 183027 [details] kscreen-doctor -o output that shows the secondary screen not being capable of brightness control SUMMARY I have two screens connected to my PC via display port, the primary screen always has a brightness control slider in the brightness menu, the secondary screen only has one some of the time. A normal start where the secondary screen doesn't have a brightness slider starts with booting the PC with only the primary screen switched on, logging in to Wayland powered KDE and then switching on the secondary screen, eventually switching off the secondary screen and continuing to use the PC and eventually shutting down the PC. Sometimes I deviate from this slightly, I either switch the secondary screen on during boot or while at the SDDM login screen, like today, and then I do sometimes get a brightness control for that screen. I have attached the output of kscreen-doctor -o from yesterday, where the screen didn't have a brightness control and no amount or combination of switching it off, disconnecting the cable and switching it back on and reconnecting the cable could convince KDE to give the screen a brightness control. In fact, kscreen-doctor is even convinced that the secondary screen is not capable of having its brightness changed. The other output is from today where the same screen now has a brightness control. Both screens are connected via a DisplayPort cable with my AMD GPU. STEPS TO REPRODUCE 1. Connect two screens via DisplayPort to a PC 2. Start the PC with one screen being switched on, the other is switched off 3. Arrive at the SDDM login screen, make sure to select KDE Wayland as the target session and login 4. Switch the secondary screen on OBSERVED RESULT The primary screen has a brightness control slider, the secondary doesn't have one. EXPECTED RESULT There should be a brightness control slider for both screens. SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 6.4.2 KDE Frameworks Version: 6.15.0 Qt Version: 6.9.1 Kernel Version: 6.15.4-arch2-1 (64-bit) Graphics Platform: Wayland Processors: 12 × AMD Ryzen 5 7600X 6-Core Processor Memory: 32 GiB of RAM (30.7 GiB usable) Graphics Processor: AMD Radeon RX 6800 XT