From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 4021ADDDF7 for ; Sat, 1 Dec 2007 09:21:47 +1100 (EST) Subject: Re: [PATCH 15/24] powerpc: early debug forces console log level to max From: Benjamin Herrenschmidt To: T Ziomek In-Reply-To: References: <20071130061200.4BAF9DDFAE@ozlabs.org> <1196456185.13230.100.camel@pasglop> Content-Type: text/plain Date: Sat, 01 Dec 2007 09:15:28 +1100 Message-Id: <1196460928.13230.111.camel@pasglop> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org Reply-To: benh@kernel.crashing.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 2007-11-30 at 16:11 -0600, T Ziomek wrote: > > Possibly, though you aren't supposed to leave EARLY_DEBUG enabled > > once you are done debugging :-) > > I'm probably not the only person that would turn it on when needed, > think > "well, no harm in leaving it on for the rest of my development, and it > might be handy; just turn it off when we're done". > > It's these kind of non-obvious but undocumented things that make a lot > of > OSS code a pain to work with for non-experts [1]. What's the harm in > giving folks a heads-up? There is no harm, I didn't say I wasn't going to document it, you do have a point there, I was just mentioning by the way, that leaving EARLY_DEBUG is generally not a good idea in production. One of the things that arhc/powerpc provides is the ability for you to have a single kernel image boot boards with different 4xx processors for example, or different fsl booke processors. You lose that if you leave early debug on as it usually contain hard coded addresses for a given board. This is typically useful if you have several revisions / versions of your product, which could use different processor revisions or even model, and want a single kernel image to support them. Ben.