The Xiaomi monitor(A27Q) is not work

The Xiaomi monitor(A27Q) was connected to our Thor custom development board via HDMI, but it remained black-screened after startup.

The attachment contains a working log for one of the HKC devices, as well as a log showing that the Xiaomi monitor does not work. Please refer to them. In addition, there is also a Hisense monitor that is not functioning properly.

logs.zip (109.9 KB)

dmesg_hkc_ok.log
1995:[   18.531298] nvidia-modeset: Loading NVIDIA UNIX Open Kernel Mode Setting Driver for aarch64  TempVersion  Release Build  (bugfix_main)  (TEST@TEST-TESTPC)  2026年 01月 19日 星期一 22:49:34 CST
2047:[   19.754998] nvidia-modeset: WARNING: HW supports 8 heads. Limiting to 4 heads
2048:[   19.755947] nvidia-modeset: WARNING: GPU:0: The head configuration (0xff) is inconsistent with the number of heads (4)
2598:[   26.940056] nvidia-modeset: GPU:0: Found active displayID: 0x200 initialized by UEFI on head 0

dmesg_xiaomi_fail.log
2897:[   38.239979] nvidia-modeset: Loading NVIDIA UNIX Open Kernel Mode Setting Driver for aarch64  TempVersion  Release Build  (bugfix_main)  (TEST@TEST-TESTPC)  2026年 01月 19日 星期一 22:49:34 CST
3141:[   39.509397] nvidia-modeset: WARNING: HW supports 8 heads. Limiting to 4 heads
3143:[   39.510351] nvidia-modeset: WARNING: GPU:0: The head configuration (0xff) is inconsistent with the number of heads (4)

Basic info:

custom board running Jetpack 7.1

# cat /etc/nv_tegra_release 
# R38 (release), REVISION: 4.0, GCID: 43443517, BOARD: generic, EABI: aarch64, DATE: Wed Dec 31 00:15:19 UTC 2025
# KERNEL_VARIANT: oot
TARGET_USERSPACE_LIB_DIR=nvidia
TARGET_USERSPACE_LIB_DIR_PATH=usr/lib/aarch64-linux-gnu/nvidia
INSTALL_TYPE=openrm

Is the custom board using the same lane routing as devkit? If order is changed, then need to update DCB.

The DCB has been updated. Some monitors support the display function, while others do not work.

Please try to do hotplug after boot up and see if it would work or not.
I mean boot up without monitor connected during boot. Only connect it when system is ready.