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Nomodeset in Meilix

Post author:meets2tarun
Post published:August 20, 2018
Post category:FOSSASIA GSoC Meilix
Post comments:0 Comments

Meilix contains configuration file which is required to config the ways of Meilix booting. There are several parameter out of which is nomodeset is one of them.

Problem:

Meilix result in blank screen in a machine which boots splash screen with a driver.

Solution:

When the OS boots, nomodeset takes care that the video like splash screen happen in kernel rather than on driver. Sometimes the driver is unable to run the video which results in blank screen issue. nomodeset confirms that no video get loaded and OS boots in BIOS mode until the driver get loaded.

Way 1:

menuentry "Try Live Meilix" {
	linux	/casper/vmlinuz  file=/cdrom/preseed/lubuntu.seed boot=casper iso-scan/filename=${iso_path} nomodeset quiet splash --
	initrd	/casper/initrd.lz
}
menuentry "Install Meilix" {
	linux	/casper/vmlinuz  file=/cdrom/preseed/lubuntu.seed boot=casper only-ubiquity iso-scan/filename=${iso_path} quiet splash --
	initrd	/casper/initrd.lz
}
menuentry "Check disc for defects" {
	linux	/casper/vmlinuz  boot=casper integrity-check iso-scan/filename=${iso_path} quiet splash --
	initrd	/casper/initrd.lz
}
menuentry "Test memory" {
	linux16	/install/mt86plus
}

We put nomodeset in Try Live Meilix option for testing purpose. This file can be found https://github.com/fossasia/meilix/edit/master/image/boot/grub/loopback.cfg.

Parameter quiet splash — is responsible for showing the splash screen and at the same time, it takes care to not to display other messages while the splash screen is loaded.

We can tweak parameter with the present options during the boot screen.

This is the one way through which we can use nomodeset while editing the configuration file.

Way 2:

During running of the OS, we can use this feature by editing this file /etc/default/grub and including nomodeset in it.

GRUB_DEFAULT=0
GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debi`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"
GRUB_CMDLINE_LINUX=""

And then save and exiting the file. Then we need to update grub using

sudo update-grub

Reference:

Configuring nomodeset

nomodeset, quiet and splash

Creating Modified Initrd for Meilix

Post author:xeon-zolt
Post published:September 5, 2017
Post category:FOSSASIA
Post comments:0 Comments

We are modifying the Initrd file in order to modify the live user configuration which is not available via skel but can be modified by editing the casper configuration like hostname or the systemd configuration.

Linux has the Initrd or “Initial ram-disk” used during the boot process. A Linux kernel is modular. The Kernel files, drivers, reside in separate files, i.e., kernel modules. The kernel does not require drivers as BIOS handles all the work of loading Initrd into the memory. After the kernel is loaded, it starts the boot process. Initrd contains all the drivers Linux needs to boot and the user can rebuild Initrd without changing the kernel.

Files inside Initrd

The files inside Initrd include the conf where the casper configuration is found which is required for the live user creation and its configuration.

The Initrd file is used when booting a live Meilix and can be found in the casper directory of the ISO.

We start with downloading the ISO and mounting it:

sudo mount -o loop meilix-i386.iso /mnt

Modifying the Initrd

Now extract the content into a folder so that one can modify them. It depends on the image type in the Meilix. We have the image in lz format it can be in gzip format for other distributions.

mkdir initrd-tmp
  cd initrd-tmp
lzma -dc -S .lz /mnt/casper/initrd.lz | cpio -id

Now we can modify the files like hostname or the files required to run during boot. The Initrd file is responsible for all the configuration available to the live user like the theme for Plymouth. We can modify the boot menu or plymouth or the files and folders the user gets like the default wallpaper.

Repack the modified files into a new initrd:

find . | cpio --quiet --dereference -o -H newc | gzip -9 > ~/new-initrd.gz

These are steps to modify the Initrd file which can be used to customize the Meilix live user configuration like hostname, Plymouth theme and user files.

Modifying the Initrd

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