From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753241Ab1JHPzp (ORCPT ); Sat, 8 Oct 2011 11:55:45 -0400 Received: from out3.smtp.messagingengine.com ([66.111.4.27]:35947 "EHLO out3.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753157Ab1JHPzl (ORCPT ); Sat, 8 Oct 2011 11:55:41 -0400 X-Sasl-enc: sImFejuAGOIcX94K87B1exefthJHL7X3YM8BIlmrcsPf 1318089339 Date: Sat, 8 Oct 2011 08:55:02 -0700 From: Greg KH To: Josh Triplett Cc: "G, Manjunath Kondaiah" , linux-arm-kernel@lists.infradead.org, Grant Likely , linux-omap@vger.kernel.org, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, Dilan Lee , Mark Brown , Manjunath@jasper.es Subject: Re: [PATCH 2/5] drivercore: Add driver probe deferral mechanism Message-ID: <20111008155502.GB616@kroah.com> References: <1317963790-29426-1-git-send-email-manjugk@ti.com> <1317963790-29426-3-git-send-email-manjugk@ti.com> <20111007064928.GE27508@kroah.com> <20111007205715.GC5275@leaf> <20111007212326.GA29003@kroah.com> <20111008040351.GA7694@leaf> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111008040351.GA7694@leaf> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 07, 2011 at 09:03:51PM -0700, Josh Triplett wrote: > On Fri, Oct 07, 2011 at 02:23:26PM -0700, Greg KH wrote: > > On Fri, Oct 07, 2011 at 01:57:15PM -0700, Josh Triplett wrote: > > > On Thu, Oct 06, 2011 at 11:49:28PM -0700, Greg KH wrote: > > > > On Fri, Oct 07, 2011 at 10:33:07AM +0500, G, Manjunath Kondaiah wrote: > > > > > +config PROBE_DEFER > > > > > + bool "Deferred Driver Probe" > > > > > + default y > > > > > + help > > > > > + This option provides deferring driver probe if it has dependency on > > > > > + other driver. Without this feature, initcall ordering should be done > > > > > + manually to resolve driver dependencies. This feature completely side > > > > > + steps the issues by allowing driver registration to occur in any > > > > > + order, and any driver can request to be retried after a few more other > > > > > + drivers get probed. > > > > > > > > Why is this even an option? Why would you ever want it disabled? Why > > > > does it need to be selected? > > > > > > > > If you are going to default something to 'y' then just make it so it > > > > can't be turned off any other way by just not making it an option at > > > > all. > > > > > > Given that the drivers which use this mechanism will not necessarily get > > > built into the kernel, I'd suggest that it should remain optional and > > > default to n. Those drivers can then add a dependency on PROBE_DEFER. > > > Let's try to avoid adding more infrastructure to the kernel that takes > > > up space even when unused; certainly embedded will appreciate not having > > > this feature unless a driver needs it. > > > > How much extra space is this "feature" really? > > Just checked: 776 bytes, 640 of text and 136 of data. We have kconfig > options for comparable amounts. > > > I don't see it being > > anything larger than the amount of memory increase that just happened as > > I typed this email as part of the ongoing memory density changes. > > I don't know about the changes you mean Moore's law. Really, 776 bytes, just always enable it, it's not worth it. greg k-h