Details of Linux kernel boot parameters

1. Environment:

Ubuntu 16.04

Linux linuxidc 4.4.0-89-generic #112-Ubuntu SMP Mon Jul 31 19:38:41 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

2. View the current linux kernel boot parameters:

cat /proc/cmdline

The output of the author is as follows:

BOOT_IMAGE=/boot/vmlinuz-4.4.0-89-generic root=UUID=bef418fa-4202-4513-b39b-cde6a5d9753f ro quiet splash vt.handoff=7

3. Start parsing

root=UUID=bef418fa-4202-4513-b39b-cde6a5d9753f : This string can be replaced by root=/dev/sda1(if the root file system is in the first partition), but not by root=(hd0,msdos1)

ro: Mounts the root file system read-only on startup

quiet: Does not print messages, so removing this will result in a lot of printed messages

splash: Show boot animation

vt. handoff=7: The graphical interface USES tty7. This prevents splash from using tty7

4. Add new startup parameters

vi /boot/grub/grub.cfg

This file will have the output of step 2, followed by an additional parameter, such as:

The author's grub.cfg file is like a downlink :(is it similar to the output in step 2?)

linux  /boot/vmlinuz-4.4.0-89-generic root=UUID=bef418fa-4202-4513-b39b-cde6a5d9753f ro  quiet splash $vt_handoff

Suppose the author wants to add the parameter dwc_ES63en. speed=1, then the modification is as follows:

linux  /boot/vmlinuz-4.4.0-89-generic root=UUID=bef418fa-4202-4513-b39b-cde6a5d9753f ro  quiet splash $vt_handoff dwc_otg.speed=1

Save the file and restart to make this parameter take effect

5. Why didn't you use ES72en-ES73en to update the ES74en. cfg file ?

The ES78en-ES79en command does not meet the need for more detailed kernel parameter modifications