https://bugs.kde.org/show_bug.cgi?id=399646
[email protected] changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |[email protected] --- Comment #28 from [email protected] --- OS: CachyOS x86_64 Host: ROG Zephyrus G16 GU605MZ Kernel: Linux 7.0.10-1-cachyos DE: KDE Plasma 6.6.5 (Wayland) CPU: Intel Core Ultra 9 185H GPU1: NVIDIA RTX 4080 (creates nvidia_0) GPU2: Intel Arc Graphics (drives OLED via intel_backlight) When KDE was installed OLED brightness didn't work. Added i915.enable_dpcd_backlight=1 to kernel parameters — fixed. When connecting an external monitor to extend displays, OLED brightness became locked to a very dim range. At 100% it was barely visible: $ cat /sys/class/backlight/intel_backlight/brightness → 100 $ cat /sys/class/backlight/intel_backlight/max_brightness → 2047 $ cat /sys/class/backlight/nvidia_0/max_brightness → 100 PowerDevil was writing to nvidia_0 (range 0–100) instead of intel_backlight (range 0–2047). Workaround — udev rule to prefer intel_backlight: SUBSYSTEM=="backlight", KERNEL=="intel_backlight", ENV{BACKLIGHT_CLASS}="raw" SUBSYSTEM=="backlight", KERNEL=="nvidia_0", ENV{BACKLIGHT_CLASS}="vendor" Plus masking systemd-backlight@nvidia_0. This works at boot, but after connecting/disconnecting an external monitor and resuming from sleep, PowerDevil reverted to nvidia_0. Running $ systemctl --user restart plasma-powerdevil fixed it immediately The bug: PowerDevil doesn't re-evaluate backlight device selection when backlight devices are added or removed at runtime with sleep thrown in into the mix I can only reproduce this intermittently (happened once so far), so I can't provide a reliable step-by-step reproducer. -- You are receiving this mail because: You are watching all bug changes.
