From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.osdl.org (smtp.osdl.org [65.172.181.24]) (using TLSv1 with cipher EDH-RSA-DES-CBC3-SHA (168/168 bits)) (Client CN "smtp.osdl.org", Issuer "OSDL Hostmaster" (not verified)) by ozlabs.org (Postfix) with ESMTP id 3B66ADDEC1 for ; Tue, 27 Feb 2007 08:17:47 +1100 (EST) Date: Mon, 26 Feb 2007 13:17:45 -0800 (PST) From: Linus Torvalds To: David Woodhouse Subject: Re: Make sure we populate the initroot filesystem late enough In-Reply-To: <1172523468.3560.2.camel@shinybook.infradead.org> Message-ID: References: <1172462466.3971.46.camel@shinybook.infradead.org> <35684e789e5c2447eab393c8946efcb9@bga.com> <1172523468.3560.2.camel@shinybook.infradead.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: linuxppc-dev@ozlabs.org, LKML , Milton Miller List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, 26 Feb 2007, David Woodhouse wrote: > > Now I'm starting to wonder if it's something the firmware sets up to DMA > to a certain region of memory, which makes it non-deterministic. And the > other things we're blaming are only making a difference because they > change the layout of what we have in memory. USB controller issues? We used to have these really hard-to-debug problems with the USB controller being active and having had the BIOS set up the command queues etc. Really subtle. It's why we now have PCI quirks for shutting up (most) USB controllers very early. If there is some USB controller that we miss, or that sets up its command chain to some unexpected area (so that USB is active and corrupting memory even very early on), that could explain it. Linus