From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756079AbaAFVoZ (ORCPT ); Mon, 6 Jan 2014 16:44:25 -0500 Received: from mailout4.w2.samsung.com ([211.189.100.14]:59852 "EHLO usmailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754517AbaAFVoY (ORCPT ); Mon, 6 Jan 2014 16:44:24 -0500 X-AuditID: cbfec37a-b7ef66d000004f2b-f2-52cb23b55375 Message-id: <52CB23B2.6070506@samsung.com> Date: Mon, 06 Jan 2014 14:44:18 -0700 From: Shuah Khan Reply-to: shuah.kh@samsung.com User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-version: 1.0 To: Greg KH Cc: rjw@rjwysocki.net, shuahkhan@gmail.com, linux-kernel@vger.kernel.org, Shuah Khan Subject: Re: [PATCH v2 1/3] drivers/bus: Add Legacy PM OPS usage check and warning to bus_register() References: <1b1d24cd7140784f96b9d1fee9cace9da04a88f5.1389034060.git.shuah.kh@samsung.com> <20140106201755.GA7339@kroah.com> <52CB1267.1000502@samsung.com> <20140106212954.GA4580@kroah.com> In-reply-to: <20140106212954.GA4580@kroah.com> Content-type: text/plain; charset=ISO-8859-1; format=flowed Content-transfer-encoding: 7bit X-Originating-IP: [105.144.21.63] X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrJLMWRmVeSWpSXmKPExsVy+t9hP92tyqeDDE6sE7VoXryezeLyrjls FmdOX2K1+PrTwYHFY+esu+we++euYffYcrWdxePzJrkAligum5TUnMyy1CJ9uwSujF9rJAoW iFW8fv2UqYHxtWAXIyeHhICJRM/+JjYIW0ziwr31QDYXh5DAMkaJqaevskI4vUwSOyauh3I2 Mkp037/HCNLCK6Al0f9pIVg7i4CqxIvWPmYQm01AXeLz6x3sILaQgJxE05LVYHFRgQiJV2cn skD0Ckr8mHwPzBYR0JB4efQWmM0skCvx5HUT2HxhgTSJT1NWQp30nlHi654PTF2MHBycAnoS 7z4zQ9RbS6yctI0RwpaX2LzmLTPEXmWJP5dPgZVLCChKbF9tNYFRZBaSzbOQdM9C0r2AkXkV o1hpcXJBcVJ6aoWhXnFibnFpXrpecn7uJkZIdFTtYLzz1eYQowAHoxIP74u9p4KEWBPLiitz DzFKcDArifCKKJ0OEuJNSaysSi3Kjy8qzUktPsTIxMEp1cAofTvjT+SbL9LK7Ac259h91NB7 6zi5u6jjdFoDz17OH1dMZ98SEX+Wq642cQ4j3359i6n5zA0sp1YtCjK6sb19R+uDY5bsZtNf 3bFsSbDjVcuPMV1QJWBzVvJ5S2Do37PNrE/sJy2N+SB9J5X35lm/5VdFk33eiEaKHK0JPsz2 71XdsqXN6w4osRRnJBpqMRcVJwIAgBjHYGwCAAA= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/06/2014 02:29 PM, Greg KH wrote: > On Mon, Jan 06, 2014 at 01:30:31PM -0700, Shuah Khan wrote: >> On 01/06/2014 01:17 PM, Greg KH wrote: >>> On Mon, Jan 06, 2014 at 01:03:21PM -0700, Shuah Khan wrote: >>>> Add Legacy PM OPS usage checks to bus_register() function. If Legacy PM OPS >>>> usage is found, print warning message to indicate that the driver code needs >>>> updating to use Dev PM OPS interfaces. This will help serve as a way to track >>>> drivers that still use Legacy PM OPS and fix them. >>>> >>>> The Legacy PM OPS check looks for suspend(struct device *, pm_message_t) or >>>> resume(struct device *) bus level interfaces. >>>> >>>> Signed-off-by: Shuah Khan >>>> --- >>>> drivers/base/bus.c | 3 +++ >>>> 1 file changed, 3 insertions(+) >>>> >>>> diff --git a/drivers/base/bus.c b/drivers/base/bus.c >>>> index 73f6c29..e8753a7 100644 >>>> --- a/drivers/base/bus.c >>>> +++ b/drivers/base/bus.c >>>> @@ -916,6 +916,9 @@ int bus_register(struct bus_type *bus) >>>> goto bus_groups_fail; >>>> >>>> pr_debug("bus: '%s': registered\n", bus->name); >>>> + if (bus->suspend || bus->resume) >>>> + pr_warn("bus '%s' needs updating - use pm pointer.\n", >>>> + bus->name); >>> >>> Why can't we just sweep the tree for all of these now, fix them up, and >>> then delete these fields and be done with it? >>> >>> Same for the other ones, putting warnings in the kernel log files >>> doesn't work at all for getting people to fix up their code (see >>> examples of scsi log messages being there for _years_ about obsolete >>> driver interfaces being used.) >> >> This change is not a simple case of replacing legacy with pm ops. I have >> been working on changing drivers that use legacy, in some cases it is an >> easy change, however in some cases it requires adding new interfaces to port >> over from legacy to pm ops. Legacy suspend/resume is more course grain and >> pm ops offer fine grain control over suspend, hibernate etc. Also it has >> been a challenge without the hardware to test. >> >> My thinking is adding warning might get the attention of individual driver >> owners. > > If it's not a trivial change, and takes a lot of work by someone who > knows this type of thing (i.e. you), then I wouldn't start making kernel > log warnings about this, it's just going to annoy a bunch of people :) ok I will continue fixing the drivers. :) > > Again, see the SCSI log warnings for examples of this, people just tune > them out, assuming someone else is going to fix the issue, someday. And > that someday never comes... > Yeah. Warnings could just get ignored. -- Shuah -- Shuah Khan Senior Linux Kernel Developer - Open Source Group Samsung Research America(Silicon Valley) shuah.kh@samsung.com | (970) 672-0658