Re: [announce] mdevd- - a mdev-compatible uevent manager

From: Didier Kryn <>
Date: Thu, 16 Nov 2017 11:25:17 +0100

Le 16/11/2017 à 10:25, Casper Ti. Vector a écrit :
> On Wed, Nov 15, 2017 at 02:53:21PM +0000, Laurent Bercot wrote:
>> Is it really the only place in Xorg that depends on libudev?
>> I'd think it would be much, much more entangled with libudev than
>> this.
> Unfortunately, just as noted by Guillermo, libudev is also, in more
> complicated ways, needed by quite a few x11 drivers and (perhaps most
> importantly) xserver itself. I apologise for (again) not thoroughly
> investigating the issues before replying :(
>> So, yeah. If you want a patch for xf86-input-evdev that will
>> make it stop depend on libudev, I can write one in an hour. But
>> that patch will likely never go upstream, because it goes against
>> policy; and complying with the policy would basically amount to
>> rewriting libudev and making a new udevd. Which I believe I'm quite
>> able to do, and better than the existing ones, but it would still be
>> bad software design, and I have no interest in contributing to the
>> problem.
> (Again, I am not someone fluent in low level programming, so please feel
> free to correct me if I make stupid mistakes in the following.)
> From my cursory glance at the x11 code that use libudev, and the libudev
> documentation, the main functionalities of libudev seem to fall into two
> almost orthogonal categories: those that abstract the sysfs interface,
> and those that handle the udev event queue. I have not come up with a
> good idea on how to provide the latter in a vender-neutral way, but a
> neutral design of the former seems obvious: if sysfs was really never
> intended to be a stable interface at all, at least make a minimalist
> library outside udev that provide the necessary functionalities.
> However, as you noted, "sysfs has not changed interfaces to the point of
> breaking stuff in 12 years and counting", so the intended instability is
> not really an excuse; and even if we pretend that sysfs is so unstable,
> stating that sysfs is "a private export only to be consumed by udev" [1]
> (ie. not mdev, nldev, vdev, etc.) has no technical basis. But noticing
> that the actors in the drama include GKH and KS, this is unsurprising;
> this is also the reason I refered to the conspiracy theory again.
> [1] <>
     I agree that there is a conspiracy. The mails exchanged by Rob
Landley are very explicit.

     I don't think Linus Torvalds would tolerate on the long term that a
group of people develop a private kernel interface for the purpose of
forcing systemd to all Linux users. In fact I guess he is aware of this,
and even sensitive to the bad quality of their code, but he will not
move because only one person complains.

     Rob Landley would have a stronger argument if a large number of
users had their desktops running mdev and undocumented changes in sysfs
breaks it.

Received on Thu Nov 16 2017 - 10:25:17 UTC

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