Configuring Linux *

In the last part we discussed evolution of the interrupt delivery process from the devices in the x86 system (PIC → APIC → MSI), general theory, and all the necessary terminology.

In this practical part we will look at how to roll back to the use of obsolete methods of interrupt delivery in Linux, and in particular we will look at Linux kernel boot options:

• pci=nomsi
• noapic
• nolapic

Also we will look at the order in which the OS looks for interrupt routing tables (ACPI/MPtable/$PIR) and what the impact is from the following boot options:

• pci=noacpi
• acpi=noirq
• acpi=off

You've probably used some combination of these options when one of the devices in your system hasn't worked correctly because of an interrupt problem. We'll go through these options and find out what they do and how they change the kernel '/proc/interrupts' interface output.

The basics of porting

Originally, Buildroot offers a limited number of packages. It makes sense — there is everything you need, but any other packages can be added.

To add a package, create 2 description files, an optional checksum file, and add a link to the package in the general package list. There are hooks at different stages of the build. At the same time, Buildroot can recognize the needed type of packages:

Overview

Once every true-linux engineer gets a trouble: there is no any software in his distro or it's built without needed options. I am keen on the phrase: "Only source control gives you freedom".

Of course, you can build this software on your computer without any src-packages, directly (with simplification: configure, make, make install). But it's a non-reproducible solution, also hard for distribution.

The better way is to make distro-aligned package that can be built if needed and that produces lightly distributed binary-packages. It's about debian-source packages(debian,ubuntu,etc), pkgbuild (for arch), ebuild for gentoo, src-rpm for red hat-based, and many others.

I will use cri-o like a specimen.

Before reading the text below I strongly recommend to get familiarized with the official Debian policy manual placed here and debhelper manpage.

Also you will be required to setup some variables like DEBMAIL and DEBFULLNAME for proper data in changelog and other places.

Tested on the following configuration:
Server: ubuntu 20.04
Clients: ubuntu 16.04, 18.04, 20.04

It doesn’t require a lot of software to create it.