Yocto grub suppressed console output (quiet)

Board Integrations Yocto Project
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1

Question

I’m using the grub-UEFI integration of mender that is based on: GitHub - mendersoftware/grub-mender-grubenv.

I would like to add the grub quiet option so that the grub console output will be suppressed or redirected to a serial port. Is there any hidden option to append the quiet option to the kernel boot options? I could not find anything in the bb files of the mender-meta layer.

The desired result is that the boot is without any log message on the screen.

Board description

  • Intel-x64-x68

Prerequirements

layer.conf


INHERIT += "mender-full"
PREFERRED_VERSION_mender-client = "3.1.0"
MENDER_STORAGE_DEVICE = "/dev/sda"
MENDER_DEVICE_TYPE="x86_64"

MENDER_FEATURES_DISABLE_append = " mender-uboot mender-image-sd mender-growfs-data"


IMAGE_ROOTFS_SIZE="1572864"
MENDER_BOOT_PART_SIZE_MB="2048"
MENDER_STORAGE_TOTAL_SIZE_MB = "6144"
MENDER_DATA_PART_SIZE_MB = "128"
2

Hi , i don’t know if this can help but maybe you can use the poky’s splash screen recipe
and change the image with a bbappend in your layer, so you will not see any log .
And , if you want a completely black screen , just put a black image :stuck_out_tongue:

3

I’ve already included that recipe, and it shows an image. Unfortunately, the welcome to GRUB message is way earlier in the boot order, so that splash will not be a solution.

4

Hi @B-Stefan welcome to community.

I had same requirement some time ago and was hacking grub but there is no way to disable it (at least one I found) other then this patch:

From 9d78a003040c0a56d729f9844b1ce311b04e9287 Mon Sep 17 00:00:00 2001
From: Marek Belisko <marek.belisko@open-nandra.com>
Date: Wed, 8 May 2019 16:28:18 +0200
Subject: [PATCH] Disable welcome to grub messages + others

Signed-off-by: Marek Belisko <marek.belisko@open-nandra.com>
---
 grub-core/kern/misc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/grub-core/kern/misc.c b/grub-core/kern/misc.c
index d1a54df..bfa5fe4 100644
--- a/grub-core/kern/misc.c
+++ b/grub-core/kern/misc.c
@@ -109,6 +109,8 @@ grub_strcpy (char *dest, const char *src)
 int
 grub_printf (const char *fmt, ...)
 {
+  return 0;
+
   va_list ap;
   int ret;

--
2.7.4

This disable all grub messages so you won’t see anything from grub at all. Hope it helps.

5

Thanks for the input and the hint for the grub solution. I’m working on it and will let you know if it worked .

For the grub env you just can modify the boot args of grub

File structure

Be aware that for all yocto .bbappend files the location is crucial

Screenshot 2022-02-03 at 20.57.41

grub-mender-grubenv_%.bbappend


FILESEXTRAPATHS_prepend_mender-client-install := "${THISDIR}/files:"
SRC_URI_append_mender-client-install = " file://03_qemu_console_grub.cfg;subdir=git"

03_qemu_console_grub.cfg


set console_bootargs="fbcon=map:2 quiet video=LVDS-1:e video=LVDS-2:e video=VGA-1:d video=HDMI-1:d"