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

occam25 · 07-10-2015, 07:37 AM

Hi,
I am running a Debian Wheezy distribution and I don't know how to show boot messages. I already erase the 'quiet' parameter from /etc/default/grub 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

I thought it was that easy 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 user 3.2.0-4-686-pae #1 SMP Debian 3.2.68-1+deb7u2 i686 GNU/Linux

thanks

EDIT: I forgot to say that I am running Debian in an embedded system and seeing the booting through a serial console. I see the grub menu, and then
Loading Linux 3.2.0-4-686-pae ...
Loading initial ramdisk ...
and nothing else until login pormpt

ondoho · 07-10-2015, 08:05 AM

did you run

Code:

grub-mkconfig -o /boot/grub/grub.cfg

after making changes to /etc/default/grub?

what is the content of your current /boot/grub/grub.cfg?
please post it (if the previous command didn't help).

occam25 · 07-10-2015, 08:19 AM

I ran

Code:

update-grub

that I think is the same

the thing is that the cmdline was changed properly because 'quiet' param disappeared as expected although the booting messages didn't show up

Code:

# cat /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 ###

ondoho · 07-10-2015, 02:03 PM

it sure looks like it should be displaying boot messages.
maybe it has something to do with watching the boot process from a remote console (if i understood that bit correctly).

occam25 · 07-10-2015, 02:17 PM

I just connect the board's serial port to my laptop and open /dev/ttyUSB0 with minicom.
Maybe I have to tell the kernel to redirect somehow the booting messages to the serial port?

Head_on_a_Stick · 07-10-2015, 02:18 PM

The boot messages in wheezy can be viewed with bootlogd
https://wiki.debian.org/bootlogd

occam25 · 07-11-2015, 06:59 AM

Thanks Head_on_a_Stick, but that's not what I want.
I want to see the messages through the serial console while it is booting, like in every embedded system I have worked on before. This is the first time it doesn't work and I don't understand why.
With a previos kernel version (3.14) I do see the booting messages so it has to be something related to the 3.2 kernel..

regards

jpollard · 07-11-2015, 07:03 AM

I think you need to tell the kernel to use a serial console...

occam25 · 07-11-2015, 07:45 AM

Sorry guys, I did a stupid mistake. I defined

Code:

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:

Code:

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

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

jpollard · 07-11-2015, 09:36 AM

Not a stupid mistake - I think it is due to the lack of grub2 documentation on what the "GRUB_SERIAL_COMMAND" does or does not do.