Message-ID: <18788.29727.163564.90030@harpo.it.uu.se>
Date:	Wed, 7 Jan 2009 10:21:35 +0100
From:	Mikael Pettersson <mikpe@...uu.se>
To:	Greg Kroah-Hartman <gregkh@...e.de>
Cc:	linux-kernel@...r.kernel.org, Kay Sievers <kay.sievers@...y.org>
Subject: Re: [PATCH 06/60] sysfs: clarify SYSFS_DEPRECATED help text

Greg Kroah-Hartman writes:
 > From: Kay Sievers <kay.sievers@...y.org>
 > 
 > This should make the help text of SYSFS_DEPRECATED more clear, that this
 > is _not_ about (what some people think it is) suppressing a few symlinks
 > and variables, but a different sysfs _layout_ with new features.
 > 
 > Signed-off-by: Kay Sievers <kay.sievers@...y.org>
 > Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>
 > ---
 >  init/Kconfig |   44 +++++++++++++++++++++++++++-----------------
 >  1 files changed, 27 insertions(+), 17 deletions(-)
 > 
 > diff --git a/init/Kconfig b/init/Kconfig
 > index 52847ee..d9d3dba 100644
 > --- a/init/Kconfig
 > +++ b/init/Kconfig
 > @@ -423,27 +423,37 @@ config SYSFS_DEPRECATED
 >  	bool
 >  
 >  config SYSFS_DEPRECATED_V2
 > -	bool "Create deprecated sysfs files"
 > +	bool "Create deprecated sysfs layout for older userspace tools"
 >  	depends on SYSFS
 >  	default y
 >  	select SYSFS_DEPRECATED
 >  	help
 > -	  This option creates deprecated symlinks such as the
 > -	  "device"-link, the <subsystem>:<name>-link, and the
 > -	  "bus"-link. It may also add deprecated key in the
 > -	  uevent environment.
 > -	  None of these features or values should be used today, as
 > -	  they export driver core implementation details to userspace
 > -	  or export properties which can't be kept stable across kernel
 > -	  releases.
 > -
 > -	  If enabled, this option will also move any device structures
 > -	  that belong to a class, back into the /sys/class hierarchy, in
 > -	  order to support older versions of udev and some userspace
 > -	  programs.
 > -
 > -	  If you are using a distro with the most recent userspace
 > -	  packages, it should be safe to say N here.
 > +	  This option switches the layout of sysfs to the deprecated
 > +	  version.
 > +
 > +	  The current sysfs layout features a unified device tree at
 > +	  /sys/devices/, which is able to express a hierarchy between
 > +	  class devices. If the deprecated option is set to Y, the
 > +	  unified device tree is split into a bus device tree at
 > +	  /sys/devices/ and several individual class device trees at
 > +	  /sys/class/. The class and bus devices will be connected by
 > +	  "<subsystem>:<name>" and the "device" links. The "block"
 > +	  class devices, will not show up in /sys/class/block/. Some
 > +	  subsystems will suppress the creation of some devices which
 > +	  depend on the unified device tree.
 > +
 > +	  This option is not a pure compatibility option that can
 > +	  be safely enabled on newer distributions. It will change the
 > +	  layout of sysfs to the non-extensible deprecated version,
 > +	  and disable some features, which can not be exported without
 > +	  confusing older userspace tools. Since 2007/2008 all major
 > +	  distributions do not enable this option, and ship no tools which
 > +	  depend on the deprecated layout or this option.
 > +
 > +	  If you are using a new kernel on an older distribution, or use
 > +	  older userspace tools, you might need to say Y here. Do not say Y,
 > +	  if the original kernel, that came with your distribution, has
 > +	  this option set to N.

Instead of making vague references to "older" tools, could someone
please make a list of the major tools that depend on sysfs, and the
minimal/oldest versions needed for the non-deprecated layout?

/Mikael
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