Ampere Altra ARM64 Grub Cannot Output Message To Serial Console

This issue is a little bit anomalous. Different boards and different combinations have different results.

For current ARM64 systems, most of the time they will use the serial console as the debug console. So, when there is no output from the serial console, it confuses me.

CPU: Ampere Altra Family
Board: AsRock ALTRAD8UD
For example, on my Gentoo system, only need to configure /etc/default/grub to following configuration.

GRUB_TIMEOUT=30
GRUB_TIMEOUT_STYLE=menu
GRUB_CMDLINE_LINUX_DEFAULT="domdadm console=ttyAMA0 pcie_aspm=off"
GRUB_TERMINAL=console

Output to serial console will be no problem, but on the Ubuntu 22.04, it cannot output to serial console.

So, on Ubuntu, if you only can see grub menu on VGA and cannot see it on serial console, try this configuration, it will output to serial console and VGA console at the same time.

GRUB_TIMEOUT_STYLE=menu
GRUB_TIMEOUT=10
GRUB_TERMINAL=serial
GRUB_SERIAL_COMMAND="serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"

Don’t forget to update grub.cfg

update-grub2

ref.
https://help.ubuntu.com/community/SerialConsoleHowto