From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751359AbWERQA1 (ORCPT ); Thu, 18 May 2006 12:00:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751370AbWERQA1 (ORCPT ); Thu, 18 May 2006 12:00:27 -0400 Received: from cantor.suse.de ([195.135.220.2]:46289 "EHLO mx1.suse.de") by vger.kernel.org with ESMTP id S1751359AbWERQA0 (ORCPT ); Thu, 18 May 2006 12:00:26 -0400 From: Andi Kleen To: michael@ellerman.id.au Subject: Re: [RFC/PATCH] Make printk work for really early debugging Date: Thu, 18 May 2006 18:00:21 +0200 User-Agent: KMail/1.9.1 Cc: linux-kernel@vger.kernel.org, Benjamin Herrenschmidt References: <20060518091410.CC527679F4@ozlabs.org> <1147966886.8469.4.camel@localhost.localdomain> In-Reply-To: <1147966886.8469.4.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200605181800.21829.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 18 May 2006 17:41, Michael Ellerman wrote: > On Thu, 2006-05-18 at 15:55 +0200, Andi Kleen wrote: > > Michael Ellerman writes: > > > > > Currently printk is no use for early debugging because it refuses to actually > > > print anything to the console unless cpu_online(smp_processor_id()) is true. > > > > On x86-64 this is simply solved by setting the boot processor online very early. > > Yeah, someone suggested that. Unfortunately it doesn't work, we actually > want to call printk before we even know which cpu we're on :D You mean smp_processor_id() returns a random value? Then your patch is broken too because iirc it tested smp_processor_id() before that other flag -Andi