Editing Udev (section)

==History==
udev was introduced in [[Linux kernel version history|Linux 2.5]]. The Linux kernel version 2.6.13 introduced or updated a new version of the [[uevent]] interface. A system using a new version of udev will not boot with kernels older than 2.6.13 unless udev is disabled and a traditional {{mono|/dev}} directory is used for device access.

In April 2012, udev's [[codebase]] was merged into the [[systemd]] source tree, making systemd 183 the first version to include udev.<ref name=":0" /><ref>{{cite mailing list |last=Sievers |first=Kay |title=The future of the udev source tree |url=http://article.gmane.org/gmane.linux.hotplug.devel/17392 |mailing-list=linux-hotplug|date=2012-04-03|access-date=2013-05-22}}</ref><ref>{{citation |last=Sievers |first=Kay |title=Commit importing udev into systemd |url=http://cgit.freedesktop.org/systemd/systemd/commit/?id=19c5f19d69bb5f520fa7213239490c55de06d99d |work=systemd |access-date=2013-05-22}}</ref> In October 2012, [[Linus Torvalds]] criticized [[Kay Sievers]]'s approach to udev maintenance and bug fixing related to [[firmware]] loading, stating:<ref>{{cite mailing list|url=https://lkml.org/lkml/2012/10/3/484|title=Re: udev breakages|author=Linus Torvalds|mailing-list=linux-kernel|date=2012-10-03|access-date=2014-10-28}}</ref>

{{quote|Yes, doing it in the kernel is "more robust". But don't play games, and stop the lying. It's more robust because we have maintainers that care, and because we know that regressions are not something we can play fast and loose with. If something breaks, and we don't know what the right fix for that breakage is, we ''revert'' the thing that broke. So yes, we're clearly better off doing it in the kernel. Not because firmware loading cannot be done in user space. But simply because udev maintenance since Greg gave it up has gone downhill.}}

In 2012, the [[Gentoo Linux]] project created a [[fork (software development)|fork]] of systemd's udev codebase in order to avoid dependency on the systemd architecture. The resulting fork is called ''[[eudev]]'' and it makes udev functionality available without systemd. A stated goal of the project is to keep eudev independent of any [[Linux distribution]] or [[init]] system.<ref>{{cite web|url=https://github.com/gentoo/eudev/blob/master/README.md|title=gentoo/eudev – README.md|website=[[GitHub]] |access-date=2017-12-25}}</ref> The Gentoo project describes eudev as follows:<ref>{{cite web|url=https://wiki.gentoo.org/wiki/Project:Eudev|title=Gentoo Linux Projects – Gentoo eudev project|access-date=2017-12-25|archive-date=2015-09-04|archive-url=https://web.archive.org/web/20150904074508/https://wiki.gentoo.org/wiki/Project:Eudev|url-status=dead}}</ref>

{{quote|eudev is a fork of systemd-udev with the goal of obtaining better compatibility with existing software such as [[OpenRC]] and [[Upstart (software)|Upstart]], older kernels, various toolchains and anything else required by users and various distributions.}}

On May 29, 2014, support for firmware loading through udev was dropped from systemd, as it has been decided that it is the kernel's task to load firmware.<ref>{{cite web |url=http://lists.freedesktop.org/archives/systemd-devel/2014-May/019587.html |title=[systemd-devel] [PATCH] Drop the udev firmware loader |date=2014-05-29}}</ref> Two days later, [[Lennart Poettering]] suggested this patch be postponed until [[kdbus]] starts to be utilized by udev; at that point, the plan was to switch udev to use kdbus as the underlying messaging system, and to get rid of the userspace-to-userspace netlink-based transport.<ref>{{cite web |url=http://lists.freedesktop.org/archives/systemd-devel/2014-May/019657.html |title=[systemd-devel] [PATCH] Drop the udev firmware loader |date=2014-05-31}}</ref>