LKML Archive on
help / color / mirror / Atom feed
From: Kay Sievers <>
To: Pierre Ossman <>
Cc: Greg KH <>, LKML <>
Subject: Re: No more "device" symlinks for classes
Date: Sun, 14 Jan 2007 01:35:51 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Sun, 2007-01-14 at 01:29 +0100, Pierre Ossman wrote:
> Kay Sievers wrote:
> >
> > The plan is to have a single unified tree at /sys/devices, where all
> > device-directories live below their parents, and /sys/class contains
> > only symlinks pointing into this single tree, just like /sys/bus.
> >
> > People want to stack class-devices, but this leads to a /sys/devices
> > tree and several small trees spread around in /sys/class. These trees
> > need to be connected by "device"-links and the "class:"-links, which
> > just doesn't make much sense if you can have one single tree with the
> > same information.
> >
> > In the unified tree, the "device"-link will always just point to the
> > parent device, that's why there is a config option to disable these
> > links and test current software not to depend on it.
> >
> I'm not sure I completely follow. Should an application look at the
> symlink (e.g. /sys/class/fooclass/foodev -> /sys/devices/...) and follow
> that one level up? If so, then this sounds a bit complicated. Especially
> from shell scripts.

We would have one single tree at /sys/devices, and always flat
classification without hierarchy at /sys/class and /sys/bus. If you
enter the device-tree by starting at /sys/class, you get the full path
to the device by reading the link, and get all the device's
dependencies(parents) in the devpath of the device,

I can't see any problem stripping the last element of a path with a
shell script. It's all implemented in current udev and HAL for quite
some time and it's pretty easy.


  reply	other threads:[~2007-01-14  0:36 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-13 23:51 Pierre Ossman
2007-01-14  0:02 ` Kay Sievers
2007-01-14  0:29   ` Pierre Ossman
2007-01-14  0:35     ` Kay Sievers [this message]
2007-01-14  6:10 ` Andrey Borzenkov
2007-01-14  7:39   ` Greg KH
2007-01-14  8:46     ` Kay Sievers

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \
    --subject='Re: No more "device" symlinks for classes' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).