Re: Network: convert network devices to use struct device instead of class_device

From: Greg KH <greg@kroah.com>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Stephen Hemminger <shemminger@linux-foundation.org>,
	Jeff Garzik <jeff@garzik.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	netdev <netdev@vger.kernel.org>,
	Kay Sievers <kay.sievers@vrfy.org>
Subject: Re: Network: convert network devices to use struct device instead of class_device
Date: Thu, 8 Feb 2007 16:56:02 -0800	[thread overview]
Message-ID: <20070209005601.GE30794@kroah.com> (raw)
In-Reply-To: <d120d5000702080929r7016de12k292add26a0a72291@mail.gmail.com>

On Thu, Feb 08, 2007 at 12:29:12PM -0500, Dmitry Torokhov wrote:
> On 2/8/07, Stephen Hemminger <shemminger@linux-foundation.org> wrote:
> >On Thu, 08 Feb 2007 07:43:18 -0500
> >Jeff Garzik <jeff@garzik.org> wrote:
> >
> >> Linux Kernel Mailing List wrote:
> >> > Gitweb:     
> >http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=43cb76d91ee85f579a69d42bc8efc08bac560278
> >> > Commit:     43cb76d91ee85f579a69d42bc8efc08bac560278
> >> > Parent:     2943ecf2ed32632473c06f1975db47a7aa98c10f
> >> > Author:     Greg Kroah-Hartman <gregkh@suse.de>
> >> > AuthorDate: Tue Apr 9 12:14:34 2002 -0700
> >> > Committer:  Greg Kroah-Hartman <gregkh@suse.de>
> >> > CommitDate: Wed Feb 7 10:37:11 2007 -0800
> >> >
> >> >     Network: convert network devices to use struct device instead of 
> >class_device
> >> >
> >> >     This lets the network core have the ability to handle 
> >suspend/resume
> >> >     issues, if it wants to.
> >
> >It fixes a non-problem. I would like to see the network core suspend/resume
> >proposal as well. Last time I examined doing network core suspend help,
> >the problem was that the physical device suspend was called before the
> >class device. It is not clear how this change would help.
> 
> If physical devices are registered before class devices then when
> suspending class devices are naturally suspended first. It is still
> not clear to me why we need to convert everythign to struct device, I
> believe I've shown (with patches) that it is possible to integrate
> struct class_device into PM framework and avoid reshuffling half of
> the kernel code.

I don't want to have two separate device trees in the kernel (well, one
big device tree and a bunch of little class_device trees.)  The code
duplication in the class_device code is just too much, and I get
questions all the time as to what the differences are.

With these slow and gradual changes, we are getting a true, unified,
device tree, and it will reduce the amount of code and complexity we
need to maintain and fix in the driver core itself.

And it should also alow for proper power management functionality, using
the changes that Linus put into the driver core about 8 months ago.

Don't worry, I have input patches queued up next for you Dmitry :)

thanks,

greg k-h