Como mostrar as mensagens de boot do kernel modificando os arquivos de configuração do grub

Question

/etc/default/grub no OpenSUSE Leap 42.2 é como abaixo. Como posso alterar este arquivo para poder ver as mensagens do kernel em tempo de inicialização:

# If you change this file, run 'grub2-mkconfig -o /boot/grub2/grub.cfg' afterwards to update
# /boot/grub2/grub.cfg.

# Uncomment to set your own custom distributor. If you leave it unset or empty, the default
# policy is to determine the value from /etc/os-release
GRUB_DISTRIBUTOR=
GRUB_DEFAULT=saved
GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=8
GRUB_CMDLINE_LINUX_DEFAULT="resume=/dev/sda4 splash=silent quiet showopts"
GRUB_CMDLINE_LINUX=""

# Uncomment to automatically save last booted menu entry in GRUB2 environment

# variable 'saved_entry'
# GRUB_SAVEDEFAULT="true"
#Uncomment to enable BadRAM filtering, modify to suit your needs

# This works with Linux (no patch required) and with any kernel that obtains
# the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
# GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"
#Uncomment to disable graphical terminal (grub-pc only)

GRUB_TERMINAL="gfxterm"
# The resolution used on graphical terminal
#note that you can use only modes which your graphic card supports via VBE

# you can see them in real GRUB with the command 'vbeinfo'
GRUB_GFXMODE="auto"
# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
# GRUB_DISABLE_LINUX_UUID=true
#Uncomment to disable generation of recovery mode menu entries

# GRUB_DISABLE_LINUX_RECOVERY="true"
#Uncomment to get a beep at grub start

# GRUB_INIT_TUNE="480 440 1"
GRUB_BACKGROUND=/boot/grub2/themes/openSUSE/background.png
GRUB_THEME=/boot/grub2/themes/openSUSE/theme.txt
SUSE_BTRFS_SNAPSHOT_BOOTING="true"
GRUB_USE_LINUXEFI="true"
GRUB_DISABLE_OS_PROBER="false"
GRUB_ENABLE_CRYPTODISK="n"

    

Answer 1

Remover quiet e splash geralmente faz o trabalho. Mude isso:

GRUB_CMDLINE_LINUX_DEFAULT="resume=/dev/sda4 splash=silent quiet showopts"

para

GRUB_CMDLINE_LINUX_DEFAULT="resume=/dev/sda4 showopts"

Na verdade, uso initcall_debug e no_console_suspend para obter o máximo de detalhes possível para a depuração, mas se tudo estiver funcionando bem, esses parâmetros extras não farão diferença alguma.

Não se esqueça de executar grub2-mkconfig -o /boot/grub2/grub.cfg depois de alterar o arquivo.