From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756577Ab3LSWcV (ORCPT ); Thu, 19 Dec 2013 17:32:21 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:46474 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754699Ab3LSWcU (ORCPT ); Thu, 19 Dec 2013 17:32:20 -0500 Date: Thu, 19 Dec 2013 14:32:23 -0800 From: Greg Kroah-Hartman To: Scott Wood Cc: Stuart Yoder , Kim Phillips , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" , "Bharat.Bhushan@freescale.com" , "christoffer.dall@linaro.org" , "alex.williamson@redhat.com" , "a.motakis@virtualopensystems.com" , "agraf@suse.de" , Varun Sethi Subject: Re: [REPOST][PATCH 1/2] driver core: Add new device_driver flag to allow binding via sysfs only Message-ID: <20131219223223.GA2801@kroah.com> References: <20131203123446.42fbff34a8ebd7afd38159a5@linaro.org> <20131219010729.GC23055@kroah.com> <1387484531.3140.134.camel@snotra.buserror.net> <20131219203401.GA11290@kroah.com> <20131219214336.GA24629@kroah.com> <1387491303.3140.156.camel@snotra.buserror.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1387491303.3140.156.camel@snotra.buserror.net> User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 19, 2013 at 04:15:03PM -0600, Scott Wood wrote: > On Thu, 2013-12-19 at 13:43 -0800, Greg Kroah-Hartman wrote: > > On Thu, Dec 19, 2013 at 09:06:21PM +0000, Stuart Yoder wrote: > > > > > > > > > > -----Original Message----- > > > > From: Greg Kroah-Hartman [mailto:gregkh@linuxfoundation.org] > > > > Sent: Thursday, December 19, 2013 2:34 PM > > > > To: Wood Scott-B07421 > > > > Cc: Kim Phillips; linux-kernel@vger.kernel.org; kvm@vger.kernel.org; > > > > Bhushan Bharat-R65777; Yoder Stuart-B08248; christoffer.dall@linaro.org; > > > > alex.williamson@redhat.com; a.motakis@virtualopensystems.com; > > > > agraf@suse.de; Sethi Varun-B16395 > > > > Subject: Re: [REPOST][PATCH 1/2] driver core: Add new device_driver flag > > > > to allow binding via sysfs only > > > > > > > > No. But you can use bind/unbind along with the existing new_id file to > > > > get what you want today. > > > > > > Yes, but that only works for PCI. > > > > No, not only PCI. > > > > > There is no such concept for platform drivers. > > > > Then fix that. > > We've already explained why that would be bad. No you haven't, or if you have, my squirrel-brain doesn't remember it... > > Or make your device not be a platform device, odds are that's the better > > solution in the end, right? > > How would that solve anything? We'd just be talking about there not > being such a mechanism for the device tree "bus" instead. Nope, you could add it there, like PCI and other busses have. > > > > I don't like this patch as we are adding lots of special and odd logic > > > > to the core, for use by almost no one, which ensures that it will never > > > > get tested, and will probably get broken in some subtle way in the > > > > future. > > > > > > It certainly will be used by users of vfio-platform. > > > > > > Here is the problem-- the new platform device "match_any_dev" mechanism > > > in patch 2 of this series is not going to work without "sysfs_bind_only". > > > A platform driver that just sets "match_any_dev" will grab any or all > > > platform devices during normal bus probing. > > > > No it will not, it will fail in the probe function as it knows to not > > grab the device, just like any driver for other busses that say it can > > "handle all Intel PCI devices" and the like. > > How will it "know not to grab the device"? The knowledge of whether the > binding was explicitly requested or not does not get passed through to > the probe function. Nor should it, as a driver should not know, nor care about this. It's up to the BUS to handle this if it really wants to, and I'm afraid that I really am not convinced that the driver core needs to handle it either. But again, as you don't have anything that could actually use this code that is mergable, it's a totally moot point, sorry. greg k-h