Grub options: some explanations


Back to the home page


Some Grub options in Linux Mint


Contents of this page:

Source of the information on this page: http://askubuntu.com/a/716966


Although specified in GRUB, the kernel parameters described below, influence the loading of the kernel or of its modules. They don't change the behaviour of Grub itself.

Hacking method

1. This page is about the parameters nomodeset, noacpi, noapic, nolapic and quiet splash. You can add any of the first four parameters permanently to Grub (the fifth one, quiet splash, is already enabled by default). Adding a parameter can be done in the following way:

a. Launch a terminal window.
(You can launch a terminal window like this: *Click*)


b. Then type in the terminal (use copy/paste):

xed admin:///etc/default/grub

Press Enter.


c. Find the following line:

GRUB_CMDLINE_LINUX=""

Place the parameter (for example: nomodeset) between the quotation marks. For example:

GRUB_CMDLINE_LINUX="nomodeset"

Save the modified configuration file and close it.


d. Then run in the terminal (note the dash in the command!):

sudo update-grub


e. Finally, reboot.

nomodeset

2. The newest kernels have moved the video mode setting into the kernel. So all the programming of the hardware specific clock rates and registers on the video card happen in the kernel, rather than in the X driver when the X server starts.

This makes it possible to have high resolution nice looking splash (boot) screens and flicker free transitions from boot splash to login screen.

Unfortunately, on some cards the kernel video mode setting doesn't work properly and you end up with a black screen. Adding the nomodeset parameter instructs the kernel to not load video drivers and use BIOS modes instead until X is loaded.

Note: Many open source drivers have removed support for non-kernel mode setting. So in those cases, when you use nomodeset, you will end up falling back to the very basic VESA unaccelerated driver....

noacpi, noapic and nolapic

3. In general, such boot parameters are not needed unless there is a problem with your BIOS and how it handles these standards, or it just might be old enough where these standards were not fully implemented properly.

ACPI (Advanced Configuration and Power Interface) is a standard for handling power management. Older systems may not support ACPI full, so sometimes it helps to give the kernel a hint to not use it.

For disabling it, use "acpi=off" or "noacpi".

APIC (Advanced Programmable Interrupt Controller) is a kind of feature found on newer systems. The "local" version is called "LAPIC".

What this controller can do is be set up to generate and handle interrupts, a signal the hardware uses to pass messages. Again, some implementations of APIC can have problems on older systems, and so it is useful to disable it on those systems.

For disabling it, use "noapic" and "nolapic".

Sometimes the APIC is working, but it slows things down by getting in the middle of messages being passed around. This can mess with audio and video processing, for example. Folks might disable it for that reason as well.

quiet and splash

4. The two parameters quiet and splash are different from the other parameters, because they're enabled by default.

The parameter splash (which eventually ends up in your /boot/grub/grub.cfg) causes the nice splash screen to be shown (usually a small logo of your Linux distribution). At the same time you want the boot process to shut up about itself, as otherwise all kinds of boot messages would disrupt that nice splash screen. The parameter quiet takes care of that.

It's useful to disable both quiet and splash temporarily, when you wish to troubleshoot boot problems. Because then you get to see all of the boot messages. So you have to remove both the parameters quiet and splash if you want to see the boot messages. Don't forget to run sudo update-grub after removing them.

Want more tips?

5. Do you want more tips and tweaks? There's a lot more of them on this website!

For example:

Speed up your Linux Mint!

Clean your Linux Mint safely

Avoid 10 fatal mistakes


To the content of this website applies a Creative Commons license.

Back to the home page

Disclaimer