Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752731Ab0GJV2z (ORCPT ); Sat, 10 Jul 2010 17:28:55 -0400 Received: from terminus.zytor.com ([198.137.202.10]:52608 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751614Ab0GJV2y (ORCPT ); Sat, 10 Jul 2010 17:28:54 -0400 Message-ID: <4C38E5D8.30408@zytor.com> Date: Sat, 10 Jul 2010 14:27:52 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.10) Gecko/20100621 Fedora/3.0.5-1.fc13 Thunderbird/3.0.5 MIME-Version: 1.0 To: Pekka Enberg CC: Yinghai Lu , x86@kernel.org, linux-kernel@vger.kernel.org, Cyrill Gorcunov , Ingo Molnar Subject: Re: [PATCH v2] x86: Early-boot serial I/O support References: <1278790820-1817-1-git-send-email-penberg@cs.helsinki.fi> <4C38DCD3.8020302@kernel.org> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1491 Lines: 41 On 07/10/2010 02:17 PM, Pekka Enberg wrote: > Hi! > > On Sat, Jul 10, 2010 at 11:49 PM, Yinghai Lu wrote: >> can you analyze "console=uart8250,io,0x3f8,115200n8" instead? >> >> that is equal to "earlyprintk=ttyS0,115200 console=ttyS0,115200" >> >> so we only use one for all. >> >> also like to kill earlyprintk=ttyS0,115200 to favor earlycon > > hpa, what's your take on this? > > The 'console' variant seems overly complicated to me. We can add it > but we also need to check for 'earlyprintk' as long as it's supported > by the kernel. > earlyprintk= seems to be preferred over console= these days. Quite frankly it's idiotic to have the user enter as many low-level details as one has to do for the console= one. Now, as for the I/O base, the I/O base for legacy serial ports are available from a 4-element u16 array starting at absolute address 0x400. I don't think Linux currently examines that array -- instead relying on the hard-coded values 0x3f8, 0x2f8, 0x3e8, 0x2e8 -- but it might something to consider for the future. However, we should match the serial port subsystem there, of course. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- 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/