For reboot and power off to work in Debian 12 (Bookworm), I created a file /etc/modprobe.d/no_hsuart_dma.conf and ran
sudo update-initramfs -u
. The file should contain the following:
Code:
blacklist dw_dmac_core
install dw_dmac /bin/true
install dw_dmac_core /bin/true
Before I did this, initiating a reboot or power off from the OS would result in the system staying powered on, frozen with a blank screen. After the above change, it works as expected.
In my testing under Debian, CPU frequency and network throughput are the same whether or not a display is attached. However, there was an unconfirmed report in the OpenWrt forum that under OpenWrt 22.03.4, the CPU and network will be throttled if the unit is powered on without something connected to the DisplayPort. I haven't done any testing in OpenWrt to confirm or deny.