Hello!
My monitor automatically wakes up shortly after being shutdown (either by inactivity or manually running kscreen-doctor --dpms off). Disconnecting mouse/keyboard before turning off the screen makes no change, so it is unlikely an issue with the input devices.
I tried disabling the DDC support in powerdevil (as described here). This makes observable changes in journalctl, with the DDCA_EVENT_DISPLAY_DISCONNECTED/DDCA_EVENT_DISPLAY_CONNECTED messages disappeared, but the issue is still present.
The issue was not present until recently. I use Arch Linux and just updated to Plasma 6.6, and it is likely some new problem with the userspace.
System information:
OS: Arch Linux x86_64
Host: MS-7D76 (2.0)
Kernel: Linux 6.18.9-arch1-2
Uptime: 7 hours, 27 mins
Packages: 1067 (pacman)
Shell: fish 4.5.0
Display (Redmi 27 NQ): 2560x1440 @ 1.25x in 27", 60 Hz [External]
DE: KDE Plasma 6.6.0
WM: KWin (Wayland)
WM Theme: Breeze 微风
Theme: Breeze (AbsoluteDark) [Qt], Breeze-Dark [GTK2], Breeze [GTK3/4]
Icons: Win11 [Qt], Win11 [GTK2/3/4]
Font: 微软雅黑 (10pt) [Qt], 微软雅黑 (10pt) [GTK2/3/4]
Cursor: breeze (24px)
Terminal: alacritty 0.16.1
Terminal Font: Hack (11.0pt, Regular)
CPU: AMD Ryzen 9 7900X (24) @ 5.74 GHz
GPU 1: AMD Radeon RX 6750 XT [Discrete]
GPU 2: AMD Raphael [Integrated]
Memory: 5.68 GiB / 30.50 GiB (19%)
Swap: Disabled
Disk (/): 330.32 GiB / 952.87 GiB (35%) - btrfs
Disk (/mnt/data): 259.33 GiB / 3.64 TiB (7%) - btrfs
Local IP (wlp15s0): 192.168.71.9/24
Locale: zh_CN.UTF-8
Helps appreciated!