From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [Ksummit-2009-discuss] Representing Embedded Architectures at the Kernel Summit Date: Tue, 16 Jun 2009 21:26:02 -0700 Message-ID: <4A38705A.3060007@zytor.com> References: <1243956140.4229.25.camel@mulgrave.int.hansenpartnership.com> <4A373EE6.6070201@compulab.co.il> <8bd0f97a0906160106g333eb222idd0d694f452650ff@mail.gmail.com> <20090616121909.GA1547@linux-mips.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090616121909.GA1547@linux-mips.org> Sender: linux-embedded-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Ralf Baechle Cc: Mike Frysinger , Mike Rapoport , James Bottomley , linux-arch@vger.kernel.org, linux-embedded@vger.kernel.org, ksummit-2009-discuss@lists.linux-foundation.org Ralf Baechle wrote: > > I2C or similar busses can be a particularly annoying if they contain > essential configuration information such as memory size which is needed > long before anything else. So for far a common solution is that platforms > are carrying a private (aka redundant, ugly) early-i2c system that's just > about sufficient for this purpose. > For what it's worth, this is true for pretty much ALL systems with removable memory modules, since Serial Presence Detect (SPD) is electrically equivalent to I2C. However, on most systems, even embedded, bringing up memory falls on firmware (sometimes in the form of a boot loader) so Linux rarely sees it. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.