Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932086Ab1CQVkq (ORCPT ); Thu, 17 Mar 2011 17:40:46 -0400 Received: from opensource.wolfsonmicro.com ([80.75.67.52]:36810 "EHLO opensource2.wolfsonmicro.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755196Ab1CQVko (ORCPT ); Thu, 17 Mar 2011 17:40:44 -0400 Date: Thu, 17 Mar 2011 21:40:42 +0000 From: Mark Brown To: Greg KH Cc: Nicolas Pitre , Arnd Bergmann , andy.green@linaro.org, Linux USB list , lkml Subject: Re: RFC: Platform data for onboard USB assets Message-ID: <20110317214042.GQ31411@opensource.wolfsonmicro.com> References: <20110311164850.GT1760@opensource.wolfsonmicro.com> <20110311165642.GA9996@kroah.com> <20110311170807.GV1760@opensource.wolfsonmicro.com> <20110311172345.GA10876@kroah.com> <20110317201320.GB4035@kroah.com> <20110317201835.GM31411@opensource.wolfsonmicro.com> <20110317202614.GA3155@kroah.com> <20110317212449.GO31411@opensource.wolfsonmicro.com> <20110317213108.GA16065@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110317213108.GA16065@kroah.com> X-Cookie: Be careful! Is it classified? User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2029 Lines: 40 On Thu, Mar 17, 2011 at 02:31:08PM -0700, Greg KH wrote: > On Thu, Mar 17, 2011 at 09:24:49PM +0000, Mark Brown wrote: > > The way this is normally done is that the ethernet controller can be > > attached to a SEPROM which it reads when it powers on. This will > > contain a number of device configuration parameters, including the > > vendor IDs and the MAC address, which will be configured before the > > device makes itself available on the bus. If the system integrator has > > omitted the SEPROM then the device will come up with defaults, usually > > something like all zeros. > Ok, then again, let's deal with this on a case-by-case basis please, as > this is going to be a "rare" thing in the real world. I don't want to > encourage _any_ engineers to think that this is ok to do for USB > devices. It's really not at all rare in the embedded world - the overwhelming majority of the systems I've worked on have omitted the SEPROMS for components that are soldered down in the system. It'd be pretty insane to do it for things that are distinct USB devices but that's not the case. There are good solid engineering reasons for doing things this way if you've got any prospect of shifting any kind of volume, as well as the cost saving achieved by removing a component you also simplify and most likely speed up the production process as you can reduce the number of components that need to be programmed on each system that gets built. > Patches to fix this, for this specific PandaBoard controller are gladly > accepted. What's odd is this is explicitly a Linux development board, > so you would think that this could have been caught, and fixed, in the > hardware a long time ago, right? The way everyone resolves this stuff is by patching their kernel locally. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/