From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932417AbcKHTna (ORCPT ); Tue, 8 Nov 2016 14:43:30 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:35594 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751865AbcKHTn2 (ORCPT ); Tue, 8 Nov 2016 14:43:28 -0500 Date: Tue, 8 Nov 2016 20:43:35 +0100 From: Greg Kroah-Hartman To: "Luis R. Rodriguez" Cc: Lukas Wunner , "Rafael J. Wysocki" , Linux PM list , Alan Stern , Linux Kernel Mailing List , Tomeu Vizoso , Mark Brown , Marek Szyprowski , Kevin Hilman , Ulf Hansson , Laurent Pinchart , Lars-Peter Clausen , Grant Likely , Mauro Carvalho Chehab , Andrzej Hajda Subject: Re: [PATCH v5 2/5] driver core: Functional dependencies tracking support Message-ID: <20161108194335.GA22680@kroah.com> References: <27296716.H9VWo8ShOm@vostro.rjw.lan> <13957403.ZrB4mMbICz@vostro.rjw.lan> <2715729.9U1nlcpFb3@vostro.rjw.lan> <20161026111902.GA6447@wunner.de> <20161027152551.GA15718@kroah.com> <20161107212250.GH1764@wotan.suse.de> <20161108064541.GA13024@kroah.com> <20161108192103.GN1764@wotan.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161108192103.GN1764@wotan.suse.de> User-Agent: Mutt/1.7.1 (2016-10-04) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 08, 2016 at 08:21:04PM +0100, Luis R. Rodriguez wrote: > On Tue, Nov 08, 2016 at 07:45:41AM +0100, Greg Kroah-Hartman wrote: > > On Mon, Nov 07, 2016 at 10:22:50PM +0100, Luis R. Rodriguez wrote: > > > We have no explicit semantics to check if a driver / subsystem > > > supports deferred probe. > > > > Why would we need such a thing? > > It depends on the impact of a driver/subsystem not properly supporting > deffered probe, if this is no-op then such a need is not critical but > would be good to proactively inform developers / users so they avoid > its use, if this will cause issues its perhaps best to make this a > no-op through a check. AFAICT reviewing implications of not supporting > deferred probe on drivers/subsytsems for this framework is not clearly > spelled out, if we start considering re-using this framework for probe > ordering I'd hate to see issues come up without this corner case being > concretely considered. It should not matter to the driver core if a subsystem, or a driver, supports or does not support deferred probe. It's a quick and simple solution to a complex problem that works well. Yes, you can iterate a lot of times, but that's fine, we have time at boot to do that (and really, it is fast.) > Furthermore -- how does this framework compare to Andrzej's resource tracking > solution? I confess I have not had a chance yet to review yet but in light of > this question it would be good to know if Andrzej's framework also requires > deferred probe as similar concerns would exist there as well. I have no idea what "framework" you are talking about here, do you have a pointer to patches? thanks, greg k-h