Subject: Re: No more "device" symlinks for classes
From: Kay Sievers <kay.sievers@vrfy.org>
To: Pierre Ossman <drzeus-list@drzeus.cx>
Cc: Greg KH <greg@kroah.com>, LKML <linux-kernel@vger.kernel.org>
In-Reply-To: <45A97089.5090004@drzeus.cx>
References: <45A97089.5090004@drzeus.cx>
Content-Type: text/plain
Date: Sun, 14 Jan 2007 01:02:41 +0100
Message-Id: <1168732961.14924.39.camel@pim.off.vrfy.org>
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1350
Lines: 31

On Sun, 2007-01-14 at 00:51 +0100, Pierre Ossman wrote:
> I just wanted to know the rationale behind
> 99ef3ef8d5f2f5b5312627127ad63df27c0d0d05 (no more "device" symlink in
> class devices). I thought that was a rather convenient way of finding
> which physical device the class device was coupled to.

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.

There was a long discussion on lkml about all that, maybe a year ago,
while converting "input".

Thanks,
Kay

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/