From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752170Ab3KPLmV (ORCPT ); Sat, 16 Nov 2013 06:42:21 -0500 Received: from caramon.arm.linux.org.uk ([78.32.30.218]:42973 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751321Ab3KPLmM (ORCPT ); Sat, 16 Nov 2013 06:42:12 -0500 Date: Sat, 16 Nov 2013 11:41:34 +0000 From: Russell King - ARM Linux To: Mark Brown Cc: Andy Shevchenko , "Shevchenko, Andriy" , Florian Meier , "Koul, Vinod" , "Williams, Dan J" , Liam Girdwood , "linux-kernel@vger.kernel.org" , dmaengine , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCHv5] dmaengine: Add support for BCM2835 Message-ID: <20131116114134.GU16735@n2100.arm.linux.org.uk> References: <52864BBC.7000506@koalo.de> <1384537403.14845.131.camel@smile> <20131115175155.GQ16735@n2100.arm.linux.org.uk> <20131116112754.GT15393@sirena.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131116112754.GT15393@sirena.org.uk> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Nov 16, 2013 at 11:27:54AM +0000, Mark Brown wrote: > On Sat, Nov 16, 2013 at 11:37:54AM +0200, Andy Shevchenko wrote: > > > The reason why I was asking about I'm just wondering what we have to do > > with existing drivers. Shall we convert them to be initialized as normal > > platform drivers instead of subsys_initcall? > > We should in general be moving in that direction however it does need a > bit of care to make sure that there aren't any dependencies which do > things like discard error codes, fail to check errors or treat errors as > hard failures. I don't agree: on platforms which have done this, it's very difficult to tell from reading the kernel message log whether things came up correctly because there's soo much spew from deferred probing it's virtually impossible to tell whether component X initialised or whether that error about resource Y missing was ever resolved. The only way that can be checked is when things work (or don't) from userspace. It's soo bad on some platforms that reading the kernel boot log is a total waste of time; you don't get any useful information from it. If we want kernel boot logs to be useful, we really need to shut up *all* the drivers and subsystems whinging about being deferred probing, and only have the driver model core reporting this status - maybe only allow output about why at debug level or similar.