HDMI hotplug: 20-second black screen with only cursor visible — X driver async RandR delay

Graphics / Linux Linux
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1 
GPU: NVIDIA GeForce GTX 1660 SUPER
Driver: 570.195.03 (Open Kernel Module)
OS: Kylin V11 (kernel 5.4.18-142-generic)
Display Server: Xorg 1.20.8
Compositor: ukui-kwin_x11 1.0.3.1
  1. Boot system WITHOUT HDMI cable connected
  2. After desktop loads, plug in HDMI cable
  3. Observe: ~20 second black screen (only cursor visible, no desktop)

nvidia-bug-report.log.gz (342.8 KB)

it is normal with amd card，so i think if nvidia ddx driver has bug，x log shows “Wait for channel idle timeout”，it may cause kwin draw delay？