how to get back kernel message dmesg at boot? [solved]

[jms.gentoo]

hi,
I would like to get back the messages on boot up after grub
I guess some time ago I removed this and can't find a way to get it back

thanks

[logrusx]

hi,
I would like to get back the messages on boot up after grub
I guess some time ago I removed this and can't find a way to get it back :roll:

thanks

You mean you don't see it on the screen? Disable CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER and you should be able to see it.

Best Regards,
Georgi

[jms.gentoo]

You mean you don't see it on the screen?

yes

Disable CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER and you should be able to see it.

It's not enabled

thanks logrusx

some more info
I am using an initrd

my kernel config
https://dpaste.com/937EESNCT

grub
http://dpaste.com/BD5J4WPA9

[Hu]

OP: please describe the problem in more detail. Which of the following statements disagrees with your current system?

• When you power on the system, the firmware transfers control to grub.
• Grub prints its menu.
• Grub transfers control to Linux.
• Linux prints messages from the kernel as it initializes.
• When kernel initialization completes, all kernel messages remain on screen. The screen is not explicitly cleared, so only messages that scroll out due to new activity become unreachable.
• Messages from the initramfs or system init scripts begin to appear.
• Init script messages remain on screen when the login prompt appears.

[Chiitoo]

Is it the '--noclear' in '/etc/inittab' perhaps?

That is, for example:

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c1:12345:respawn:/sbin/agetty --noclear 38400 tty1 linux

[jms.gentoo]

Is it the '--noclear' in '/etc/inittab' perhaps?]

thanks but no changes

[jms.gentoo]

OP: please describe the problem in more detail.
Which of the following statements disagrees with your current system?.

• [*]When you power on the system, the firmware transfers control to grub.

  yes

  [*]Grub prints its menu.

  yes

  [*]Grub transfers control to Linux.

  yes

  [*]Linux prints messages from the kernel as it initializes

  well once gub transfere message to linux
  The only message I have is

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  Loading Linux x.y.z
  Loading initial ramdisk ...
  

  then no more messages
  and the the Diplay manager take over
  

  [*]When kernel initialization completes, all kernel messages remain on screen. The screen is not explicitly cleared, so only messages that scroll out due to new activity become unreachable.

  only

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  Loading Linux x.y.z
  Loading initial ramdisk ...
  

  [*]Messages from the initramfs or system init scripts begin to appear.

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  Loading Linux x.y.z
  Loading initial ramdisk ...
  

  [*]Init script messages remain on screen when the login prompt appears.

  it's straight to KDM

[jms.gentoo]

In fact I now believe my problem is related to tty /console

once in kde
I have

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loginctl
SESSION  UID USER SEAT  TTY 
      1 1000 jms  seat0 tty2

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env | grep "XDG"

XDG_CACHE_HOME=/tmp/jms/.cache
XDG_CONFIG_DIRS=/home/jms/.config/kdedefaults:/etc/xdg
XDG_CURRENT_DESKTOP=KDE
XDG_DATA_DIRS=/usr/local/share:/usr/share:/etc/eselect/wine/share
XDG_RUNTIME_DIR=/run/user/1000
XDG_SEAT=seat0
XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
XDG_SESSION_CLASS=user
XDG_SESSION_ID=1
XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session1
XDG_SESSION_TYPE=x11
XDG_VTNR=2

when logged in kde If I want to access tty using [Ctrl][Alt][F1]
I just got the tty black screen with the message

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Loading Linux x.y.z
Loading initial ramdisk ... 

and no login prompt
only [Ctrl][Alt][F2] allow me to switch back from tty to kde and not [Ctrl][Alt][F7]

[Chiitoo]

Ah, yeah, I think you would have seen the messages fly by if it was what I was thinking of (just they get cleared and you only see the login prompt without the 'noclear').

That there is nothing after "Loading Linux" etc. makes me think of the output going into a serial console maybe?

I've only done that with virtual machines a couple of times though, so not entirely sure where to look aside from the kernel command line... and perhaps that's not it either.

[szatox]

Is there "quiet" somewhere in kernel's boot command line?

[figueroa]

Perhaps you can clean something useful from selected portions of my .config:

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$ grep FRAMEB .config
CONFIG_FRAMEBUFFER_CONSOLE=y
# CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION is not set
CONFIG_FRAMEBUFFER_CONSOLE_DETECT_PRIMARY=y
# CONFIG_FRAMEBUFFER_CONSOLE_ROTATION is not set
# CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER is not set

$ grep FB .config
# CONFIG_NET_SCH_SFB is not set
CONFIG_SYSFB=y
# CONFIG_SYSFB_SIMPLEFB is not set
CONFIG_DRM_FBDEV_EMULATION=y
CONFIG_DRM_FBDEV_OVERALLOC=100
CONFIG_FB_CMDLINE=y
CONFIG_FB_NOTIFY=y
CONFIG_FB=y
CONFIG_FB_CFB_FILLRECT=y
CONFIG_FB_CFB_COPYAREA=y
CONFIG_FB_CFB_IMAGEBLIT=y
CONFIG_FB_SYS_FILLRECT=y
CONFIG_FB_SYS_COPYAREA=y
CONFIG_FB_SYS_IMAGEBLIT=y
# CONFIG_FB_FOREIGN_ENDIAN is not set
CONFIG_FB_SYS_FOPS=y
CONFIG_FB_DEFERRED_IO=y
CONFIG_FB_MODE_HELPERS=y
CONFIG_FB_TILEBLITTING=y
# CONFIG_FB_CIRRUS is not set
# CONFIG_FB_PM2 is not set
# CONFIG_FB_CYBER2000 is not set
# CONFIG_FB_ARC is not set
# CONFIG_FB_ASILIANT is not set
# CONFIG_FB_IMSTT is not set
# CONFIG_FB_VGA16 is not set
# CONFIG_FB_UVESA is not set
CONFIG_FB_VESA=y
# CONFIG_FB_N411 is not set
# CONFIG_FB_HGA is not set
# CONFIG_FB_OPENCORES is not set
# CONFIG_FB_S1D13XXX is not set
# CONFIG_FB_NVIDIA is not set
# CONFIG_FB_RIVA is not set
# CONFIG_FB_I740 is not set
# CONFIG_FB_LE80578 is not set
# CONFIG_FB_MATROX is not set
# CONFIG_FB_RADEON is not set
# CONFIG_FB_ATY128 is not set
# CONFIG_FB_ATY is not set
# CONFIG_FB_S3 is not set
# CONFIG_FB_SAVAGE is not set
# CONFIG_FB_SIS is not set
# CONFIG_FB_NEOMAGIC is not set
# CONFIG_FB_KYRO is not set
# CONFIG_FB_3DFX is not set
# CONFIG_FB_VOODOO1 is not set
# CONFIG_FB_VT8623 is not set
# CONFIG_FB_TRIDENT is not set
# CONFIG_FB_ARK is not set
# CONFIG_FB_PM3 is not set
# CONFIG_FB_CARMINE is not set
# CONFIG_FB_SMSCUFX is not set
# CONFIG_FB_UDL is not set
# CONFIG_FB_IBM_GXT4500 is not set
# CONFIG_FB_VIRTUAL is not set
# CONFIG_FB_METRONOME is not set
# CONFIG_FB_MB862XX is not set
# CONFIG_FB_SIMPLE is not set
# CONFIG_FB_SM712 is not set
# CONFIG_CRYPTO_CFB is not set
# CONFIG_CRYPTO_OFB is not set

[NeddySeagoon]

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Loading Linux x.y.z
Loading initial ramdisk ... 

is written to the console by Grub, that the kernel never outputs anything.

The kernel console driver is either missing to broken.

We need your

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lspci -nnk

output and your kernel .config file.
Uve wgetpast to post the .config file.

[Logicien]

I have make a cross trying to read the kernel and service messages at boot. It's really too fast. The only thing that count for me is to be able to see if there is only green messages or if some are red. That I can see. I don't know how to pause the boot process and even it it is possible. I use dmesg and journalctl to see the state of the boot after it is finished.

I add extra kilobytes to the console to go deeper back in time in the boot process analyse. I use the Linux kernel parameter fbcon=scrollback:2048k . Of course a quiet kernel parameter can hide most of the messages. I use loglevel=0 to see the minimum messages during boot. It's more esthetic.



With Systemd systemctl --failed tell me what I need to know from the init phase of the boot.

[figueroa]

The secret to what's happening during boot may be found in your logs (/var/log/), specifically your boot log, dmesg file. Actual files will depend on what form of logging you are using.

[jms.gentoo]

Is there "quiet" somewhere in kernel's boot command line?

no

Perhaps you can clean something useful from selected portions of my .config

thanks
the main difference I can see is the CONFIG_SYSFB_SIMPLEFB that I have set.
I think this shouldn't make a difference but I ll try and will test building the kernel without it

here are info asked by NeddySeagoon and few more.

kernel .config
http://dpaste.com/6K9GMVGSR

lspci -nnk
http://dpaste.com/758ND5AUM

[ebuild R ] sys-boot/grub-2.06-r9:2/2.06-r9::gentoo
USE="device-mapper fonts nls sdl themes truetype -doc -efiemu -libzfs -mount (-test) -verify-sig"
GRUB_PLATFORMS="efi-64 -coreboot -efi-32 -emu -ieee1275 (-loongson) -multiboot -pc -qemu (-qemu-mips) -uboot -xen -xen-32 -xen-pvh"

/etc/default/grub
http://dpaste.com/8U242NM9E

/boot/grub/grub.cfg
http://dpaste.com/4M24QYQL5

/etc/rc.conf
http://dpaste.com/DLCJEJ3UX

/etc/inittab
http://dpaste.com/4XPJ59GU2

/etc/init.d/agetty
http://dpaste.com/7TWET7LYV

/etc/conf.d/agetty
http://dpaste.com/B95LJJV2G

/etc/conf.d/dmesg
http://dpaste.com/HAGUJGFCZ

rc-update show -v
http://dpaste.com/GAX7QGXWD

It's really too fast. The only thing that count for me is to be able to see if there is only green messages or if some are red

yes I believe it will be very fast now, but I somewhat miss to see the penguin logo , green messages, fsck ...
And now as I can not seems to get it back I want it more than ever

thanks to all

[NeddySeagoon]

jms.gentoo,

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26:00.0 VGA compatible controller [0300]: NVIDIA Corporation GP107 [GeForce GTX 1050] [10de:1c81] (rev a1)
	Subsystem: Gigabyte Technology Co., Ltd GP107 [GeForce GTX 1050] [1458:3766]
	Kernel driver in use: nvidia
	Kernel modules: nvidia_drm, nvidia

That's an nVidia card using the binary blob driver.
Its the only DRM driver that does not provide a console at no extra charge.

That restricts your choice of console drivers.
Turn off

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CONFIG_SYSFB=y
CONFIG_SYSFB_SIMPLEFB=y

You will only use one of

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CONFIG_FB_VESA=y
CONFIG_FB_EFI=y

depending your firmware. BIOS will use VESA, EFI will use EFI. Building both is safe.

While we are here ...

If you want to use your

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28:00.1 Encryption controller [1080]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse Cryptographic Coprocessor PSPCPP [1022:1486]

add

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CONFIG_CRYPTO_DEV_CCP=y
CONFIG_CRYPTO_DEV_CCP_DD=y

to your kernel.
You have

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# CONFIG_CRYPTO_DEV_CCP is not set

[jms.gentoo]

That's an nVidia card using the binary blob driver.
Its the only DRM driver that does not provide a console at no extra charge.
Turn off

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CONFIG_SYSFB=y
CONFIG_SYSFB_SIMPLEFB=y	

Thank you very much
yes turning off CONFIG_SYSFB_SIMPLEFB is the solution, nvidia the culprit.
however SYSFB is needed
reverse dep: SYSFB_SIMPLEFB && (X86 || EFI) || FB_VESA && HAS_IOMEM && FB=y && X86 || FB_EFI && HAS_IOMEM && FB=y && EFI
symbol: SYSFB
select: BOOT_VESA_SUPPORT

I will mention it in the wiki talk page for nvidia. I think this should be 'better' recommended

-to me having access to the tty teletypewriter is something that I came to expect and did prove to be very useful in more than one case.
- being able to have a quick glance at the kernel boot info when booting is interesting especially when installing.

[figueroa]

Did you know that most of the time you can pause the screen output during booting with CTL/s. Then CTL/q to resume?

[jms.gentoo]

Did you know that most of the time you can pause the screen output during booting with CTL/s. Then CTL/q to resume?

I didn't. Nice trick