| Summary: | Brightness slider disappears after a few minutes of uptime | ||
|---|---|---|---|
| Product: | [Plasma] plasmashell | Reporter: | YanEx <yanexbug> |
| Component: | Power management & brightness | Assignee: | Plasma Bugs List <plasma-bugs-null> |
| Status: | RESOLVED UPSTREAM | ||
| Severity: | normal | CC: | akselmo, yanexbug |
| Priority: | NOR | ||
| Version First Reported In: | 6.5.5 | ||
| Target Milestone: | 1.0 | ||
| Platform: | CachyOS | ||
| OS: | Linux | ||
| Latest Commit: | Version Fixed/Implemented In: | ||
| Sentry Crash Report: | |||
| Attachments: | Demonstration of the problem | ||
I think this might be a bug in ddcutil, see similar type issue here https://github.com/rockowitz/ddcutil/issues/583 I'm closing this as upstream bug, since we rely on ddcutil to show that slider. |
Created attachment 189634 [details] Demonstration of the problem SUMMARY The brightness control slider for an external monitor (Philips 27M2N5500) connected via DisplayPort (USB-C) is available immediately after boot but consistently disappears from the system settings/tray after 2–5 minutes of uptime. STEPS TO REPRODUCE 1. Boot into CachyOS. 2. Confirm the brightness slider for the Philips 27M2N5500 is visible in the UI. 3. Use the system normally for a few minutes. 4. Check the brightness control again. OBSERVED RESULT The slider for the external monitor disappears. The monitor is no longer recognized as a dimmable device in the desktop environment. EXPECTED RESULT The brightness slider should remain available and functional throughout the entire session. SOFTWARE/OS VERSIONS Operating System: CachyOS Linux KDE Plasma Version: 6.5.5 KDE Frameworks Version: 6.23.0 Qt Version: 6.10.2 Kernel Version: 6.19.0-2-cachyos (64-bit) Graphics Platform: Wayland Processors: 12 × 11th Gen Intel® Core™ i5-11400H @ 2.70GHz Memory: 16 ГиБ of RAM (15.3 ГиБ usable) Graphics Processor 1: NVIDIA GeForce RTX 3060 Laptop GPU Graphics Processor 2: Intel® UHD Graphics Manufacturer: HP Product Name: Victus by HP Laptop ADDITIONAL INFORMATION This behavior is unique to CachyOS. On Fedora, the slider remains stable and functional. Output of ddcutil detect after the slider disappears: ddcutil detect Invalid display I2C bus: /dev/i2c-10 DRM_connector: card2-eDP-1 EDID synopsis: Mfg id: BOE - BOE Model: Product code: 2733 (0x0aad) Serial number: [REDACTED] Binary serial number: [REDACTED] Manufacture year: [REDACTED] This is a laptop display. Laptop displays do not support DDC/CI. Display 1 I2C bus: /dev/i2c-13 DRM_connector: card1-DP-2 EDID synopsis: Mfg id: PHL - Philips Consumer Electronics Company Model: 27M2N5500 Product code: 49976 (0xc338) Serial number: [REDACTED] Binary serial number: [REDACTED] Manufacture year: [REDACTED] VCP version: 2.2