Debian Wheezy doesn't show boot messages after deleting quiet param

Question

I am running Debian in an embedded system and seeing the booting through a serial console, but I don't know how to show boot messages.

I see the BIOS, the grub menu, and then:

Loading Linux 3.2.0-4-686-pae ...

Loading initial ramdisk ...

and nothing else until login pormpt

I already erased the 'quiet' parameter from /etc/default/grub and executed update-grub command after that. And after booting I see that the cmdline is right, without that param:

cat /proc/cmdline :

BOOT_IMAGE=/vmlinuz-3.2.0-4-686-pae root=UUID=0d645791-109e-4ce4-87be-1cc7074da5f8 ro

But it doesn't work... what else am I missing? do I need to recompile the kernel with a specific flag or what?

uname -a :

Linux hostname 3.2.0-4-686-pae #1 SMP Debian 3.2.68-1+deb7u2 i686 GNU/Linux

/boot/grub/grub.cfg

#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
  load_env
fi
set default="0"
if [ "${prev_saved_entry}" ]; then
  set saved_entry="${prev_saved_entry}"
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
fi

function savedefault {
  if [ -z "${boot_once}" ]; then
    saved_entry="${chosen}"
    save_env saved_entry
  fi
}

function load_video {
  insmod vbe
  insmod vga
  insmod video_bochs
  insmod video_cirrus
}

serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1
terminal_input serial
terminal_output serial
set timeout=2
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###
set menu_color_normal=cyan/blue
set menu_color_highlight=white/blue
### END /etc/grub.d/05_debian_theme ###

### BEGIN /etc/grub.d/10_linux ###
menuentry 'Debian GNU/Linux, with Linux 3.2.0-4-686-pae' --class debian --class gnu-linux --class gnu --class os {
    load_video
    insmod gzio
    insmod part_msdos
    insmod ext2
    set root='(hd1,msdos1)'
    search --no-floppy --fs-uuid --set=root c1265ba3-c4bd-493f-9fec-7c015099c0bc
    echo    'Loading Linux 3.2.0-4-686-pae ...'
    linux   /vmlinuz-3.2.0-4-686-pae root=UUID=0d645791-109e-4ce4-87be-1cc7074da5f8 ro  
    echo    'Loading initial ramdisk ...'
    initrd  /initrd.img-3.2.0-4-686-pae
}
menuentry 'Debian GNU/Linux, with Linux 3.2.0-4-686-pae (recovery mode)' --class debian --class gnu-linux --class gnu --class os {
    load_video
    insmod gzio
    insmod part_msdos
    insmod ext2
    set root='(hd1,msdos1)'
    search --no-floppy --fs-uuid --set=root c1265ba3-c4bd-493f-9fec-7c015099c0bc
    echo    'Loading Linux 3.2.0-4-686-pae ...'
    linux   /vmlinuz-3.2.0-4-686-pae root=UUID=0d645791-109e-4ce4-87be-1cc7074da5f8 ro single 
    echo    'Loading initial ramdisk ...'
    initrd  /initrd.img-3.2.0-4-686-pae
}
### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/41_custom ###
if [ -f  $prefix/custom.cfg ]; then
  source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###

I am stuck! any help will be appreciated!

thanks

EDIT:

Sorry guys, I did a stupid mistake. I defined

GRUB_SERIAL_COMMAND="serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1"

in /etc/default/grub

and I thought that was enough for grub to pass the serial specifications to the kernel, but of course it is not, GRUB only pass the GRUB_CMDLINE_LINUX variable to the kernel as parameter.

Adding the console parameter in the GRUB_CMDLINE_LINUX makes the kernel to receive the console settings and use the serial for messages output:

GRUB_CMDLINE_LINUX="video=off elevator=deadline console=ttyS0,115200"

Now it is working. Sorry for the stupid misunderstood and thanks for your time! :)

Answer 1

You can try adding to the kernel line where you removed quiet the options

console=tty0 console=ttyS0,115200n8

where 115200 is the speed you want. See eg ubuntu how-to.