From: Alan McKinnon <alan.mckinnon@gmail.com>
To: gentoo-user@lists.gentoo.org
Subject: Re: [gentoo-user] Re: New xorg.conf with x11-base/xorg-server-1.5.3-r5
Date: Sun, 17 May 2009 11:19:49 +0200 [thread overview]
Message-ID: <200905171119.49998.alan.mckinnon@gmail.com> (raw)
In-Reply-To: <4A0F6962.2020006@coolmail.se>
On Sunday 17 May 2009 03:33:22 pk wrote:
> Alan McKinnon wrote:
> > As I see it, at the bottom of the stack you have a kernel and at the top
> > a user space app (the X server will do for an example). Plug in a USB
> > device that the app can use, and the kernel needs to make a node in /dev
> > for it if it's not already there. The kernel should not be interrogating
> > the device for all possible info - that is expensive - and doesn't need
> > to. It only needs enough info to know what driver, major and minor
> > numbers to use. X OTOH, can
>
> I couldn't agree more. And this is what Udev, as a user space app, does.
> The only thing it doesn't handle is communicating with other user space
> apps; this is currently Hals job.
>
> > the current model uses udev as the interface to the kernel's nodes and
> > HAL as the interface to exactly what hardware you have. Seems pretty sane
> > for the most usual use case. At some point in the stack you will need the
> > OS-dependant part, my guess is the best place is between hal and udev.
> > Only Linux uses
>
> Well, as I understand it this is what it looks like today:
>
> kernel <-> udev (or equivalent for non-linux kernel/OS) <-> hal <-> dbus
> <-> user apps
>
> To me that seems a bit redundant...
No, there's nothing redundant in that. udev talks kernel-speak, hal talks
userspace-speak. Hal could be distro-agnostic, udev can't be (not in a sane
environment) and dbus is simply a transport layer for messages. That's five
different functions going on, and none of them logically belong with any other
in the same layer.
> What I would like to see:
>
> kernel <-> udev <-> user apps
Then X must talk to udev directly. Two problems:
- only Linux has udev. Other OSes may not need, want or be willing to touch
udev with a bargepole.
- X is multi-platform. Good luck getting Keith to agree to make it essentially
Linux only :-)
> Or at the most:
>
> kernel <-> udev <-> daemon <-> user apps.
But you have that in the current setup. Hal (for better or worse) is the
daemon. dbus is simply a message transport and can be omitted from the
conceptual diagram
> > udev, but all OSes use something in that spot. And if not, they have
> > static nodes.
>
> Yes, but if the developers could agree on a common API for the udev
> daemon and it's equivalents on other platforms (what does BSD use?)...
> Or if they could agree on using "Hal v2" (rewritten from scratch with no
> or a minimum of dependencies).
I don't think that's feasible. Easiest would be the bottom layer of hal has
OS-specific code to talk to udev (or it's equivalent in other OSes). Or
perhaps a plugin/module type system.
> > Meanwhile we have an acknowledged problem with hal - it's too complex,
> > too many things have been shoved into it that were never catered for in
> > the design, configuration is horrific - and the devs are having their
> > usual spirited debate about how best to approach a solution. This is
> > perfectly normal and perfectly healthy
>
> Yes, I guess so. Since I'm (currently) not in the position to help out
> I'll have to live with whatever they come up with. But sometimes it's a
> bit frustrating... Sorry for the ranting.
Hey, it could be worse.
You could be forced to use Windows...
--
alan dot mckinnon at gmail dot com
next prev parent reply other threads:[~2009-05-17 9:21 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-07 8:39 [gentoo-user] New xorg.conf with x11-base/xorg-server-1.5.3-r5 Mick
2009-04-07 8:46 ` Volker Armin Hemmann
2009-04-07 10:26 ` Mick
2009-04-07 10:46 ` Volker Armin Hemmann
2009-04-07 11:02 ` [gentoo-user] " Nikos Chantziaras
2009-04-07 11:17 ` Alan McKinnon
2009-04-07 11:25 ` Volker Armin Hemmann
2009-04-08 15:01 ` 7v5w7go9ub0o
2009-05-15 15:55 ` Tony Davison
2009-05-16 16:33 ` Mick
2009-04-07 13:08 ` [gentoo-user] " Dale
2009-04-07 10:53 ` Peter Humphrey
2009-04-07 9:19 ` Alan McKinnon
2009-04-07 10:34 ` Mick
2009-04-07 10:21 ` Khanh Nguyen
2009-04-07 14:14 ` sean
2009-04-07 14:51 ` Paul Hartman
2009-04-07 15:22 ` Volker Armin Hemmann
2009-04-07 15:50 ` Paul Hartman
2009-04-07 16:31 ` Volker Armin Hemmann
2009-04-07 18:12 ` [gentoo-user] " ABCD
2009-04-08 15:45 ` [gentoo-user] " Paul Hartman
2009-04-08 16:12 ` Volker Armin Hemmann
2009-04-08 16:18 ` Paul Hartman
2009-05-15 16:03 ` Volker Armin Hemmann
2009-05-15 16:10 ` Alan McKinnon
2009-05-15 16:41 ` Dale
2009-05-15 16:59 ` Paul Hartman
2009-05-15 17:26 ` Volker Armin Hemmann
2009-05-15 17:42 ` Dale
2009-05-15 16:42 ` Dale
2009-05-15 16:57 ` Alan McKinnon
2009-05-15 17:45 ` Dale
2009-05-15 20:05 ` pk
2009-05-15 20:24 ` Volker Armin Hemmann
2009-05-15 20:38 ` Aaron Clark
2009-05-15 20:39 ` Mark Knecht
2009-05-15 20:38 ` [gentoo-user] " Nikos Chantziaras
2009-05-15 20:44 ` Alan McKinnon
2009-05-15 20:51 ` Nikos Chantziaras
2009-05-15 20:54 ` Alan McKinnon
2009-05-16 17:14 ` pk
2009-05-16 17:55 ` Alan McKinnon
2009-05-16 18:10 ` Dale
2009-05-17 17:10 ` bn
2009-05-17 18:00 ` Alan McKinnon
2009-05-17 18:16 ` Mark Knecht
2009-05-17 19:12 ` Dale
2009-05-17 19:22 ` Mark Knecht
2009-05-17 21:20 ` Dale
2009-05-18 4:07 ` was [gentoo-user] Re: New xorg.conf with x11-base/xorg-server-1.5.3-r5 now old nvidia drivers Adam Carter
2009-05-18 4:22 ` Dale
2009-05-18 5:00 ` Adam Carter
2009-05-17 18:21 ` [gentoo-user] Re: New xorg.conf with x11-base/xorg-server-1.5.3-r5 bn
2009-05-17 19:02 ` Dale
2009-05-17 1:33 ` pk
2009-05-17 9:19 ` Alan McKinnon [this message]
2009-05-17 12:15 ` pk
2009-05-17 14:32 ` Alan McKinnon
2009-05-17 21:47 ` Volker Armin Hemmann
2009-04-07 15:52 ` [gentoo-user] " Joseph
2009-04-07 16:16 ` Neil Bothwick
2009-04-07 16:17 ` [gentoo-user] " Nikos Chantziaras
2009-04-07 23:13 ` [gentoo-user] " sean
2009-04-08 18:16 ` pk
2009-04-07 16:14 ` [gentoo-user] " Nikos Chantziaras
2009-04-07 16:45 ` [gentoo-user] " Mick
2009-04-07 17:02 ` Volker Armin Hemmann
2009-04-07 17:21 ` Mick
2009-04-07 20:27 ` sean
2009-04-07 20:32 ` Volker Armin Hemmann
2009-04-07 17:05 ` Sebastian Günther
2009-04-07 17:17 ` Mick
2009-04-07 20:37 ` Daniel Barkalow
2009-04-08 5:47 ` Mick
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