https://bugs.kde.org/show_bug.cgi?id=500997
[email protected] changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |[email protected] --- Comment #6 from [email protected] --- This is not a caching or restore issue, and not a monitor firmware limitation. On a desktop PC (no laptop panel), external HDMI monitor: - Plasma brightness slider at 100% immediately sets the monitor actual and OSD brightness to ~30. - This happens deterministically when applied. - It is scaled so 1 to 100 in the slider is 0 to 30 in real monitor brightness The DDC path and monitor are correct: - `ddcutil setvcp 10 80` → OSD shows 80 - `ddcutil setvcp 10 100` → OSD shows 100 Therefore Plasma is not writing the slider value verbatim to VCP 0x10. It is applying an incorrect normalization/scaling step before issuing the DDC write. Expected behavior: For DDC/CI monitors, slider value (0–100) should be written directly to VCP 0x10. Environment: - Plasma 6.5.5 - KWin (Wayland) - Desktop system - External HDMI monitor Relevant monitor DDC info: --------------------------------------------- > dcutil capabilities --display 1 Model: Not specified MCCS version: 2.2 Commands: Op Code: 01 (VCP Request) Op Code: 02 (VCP Response) Op Code: 03 (VCP Set) Op Code: 07 (Timing Request) Op Code: 0C (Save Settings) Op Code: E3 (Capabilities Reply) Op Code: F3 (Capabilities Request) VCP Features: Feature: 04 (Restore factory defaults) Feature: 10 (Brightness) Feature: 12 (Contrast) Feature: 14 (Select color preset) Values: 05: 6500 K 06: 7500 K 08: 9300 K 0b: User 1 -- You are receiving this mail because: You are watching all bug changes.
