guide for serial console & early printk enabling?

finofino New Member Posts: 4
edited May 20 in UP Xtreme Linux

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

Best Answers

  • finofino Posts: 4
    Accepted Answer

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

  • finofino Posts: 4
    Accepted Answer

    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.

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