guide for serial console & early printk enabling?

fino

hi Team,

on UP Xtreme board,
do have a guide for serial console & early printk enabling? on either Ubuntu or Debian,
just like wiki for UP2:
https://wiki.up-community.org/Serial_console

and 'early printk' is useful when a linux kernel image fail to boot.
I know we can google it but still handy if have a wiki/guide on UP Xtreme's support website.

BR fino

fino

well, I found on UP Xtreme (cpu is WHL8565U),
debug serial port (in M10 header ) is /dev/ttyS2

fino

tested out on Debian 10, the only necessary update in /etc/default/grub is GRUB_CMDLINE_LINUX, others are not need in most common case;

GRUB_CMDLINE_LINUX="console=tty1 console=ttyS2,115200n8"
#GRUB_TERMINAL="serial"
#GRUB_TERMINAL_INPUT="console serial"
#GRUB_TERMINAL_OUTPUT="gfxterm serial"
#GRUB_SERIAL_COMMAND="serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"

others:
if remove console=tty1 , boot time printk msg will not show on monitor, that's the only difference I found.
if u can see output in putty/minicom on host machine, but cannot input by keyboard, check your serial cable's RX/TX connection.