Cannot fully power off system after kldload nvidia-modeset

Hi, after installing the nvidia driver and kldload nvidia-modeset, I can no longer power off my system using “poweroff” command.

Without loading the driver it works fine. With it loading, poweroff command will sync all the disk, issue a message “Unloading nvidia-modeset” in console, but the system will only halt but not power down. I have to use the power button to shut it down. Because of that, it breaks my wake on LAN as well.

Further adding, issuing ACPI suspend (acpiconf -s 3) seems to work though. My driver was built from ports with ACPI PM enabled.