Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756096Ab0GLQYn (ORCPT ); Mon, 12 Jul 2010 12:24:43 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:55949 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752126Ab0GLQYm (ORCPT ); Mon, 12 Jul 2010 12:24:42 -0400 Message-ID: <4C3B40F3.6070009@kernel.org> Date: Mon, 12 Jul 2010 09:21:07 -0700 From: Yinghai Lu User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.10) Gecko/20100520 SUSE/3.0.5 Thunderbird/3.0.5 MIME-Version: 1.0 To: "H. Peter Anvin" CC: Pekka Enberg , Ingo Molnar , Thomas Gleixner , Andrew Morton , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] x86: Setup early console as early as possible References: <4C3A3B27.7020009@oracle.com> <4C3AD94C.7070807@cs.helsinki.fi> <4C3B38F7.1050400@zytor.com> In-Reply-To: <4C3B38F7.1050400@zytor.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Source-IP: acsmt353.oracle.com [141.146.40.153] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090204.4C3B418F.00FC,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1953 Lines: 64 On 07/12/2010 08:47 AM, H. Peter Anvin wrote: > On 07/12/2010 01:58 AM, Pekka Enberg wrote: >> Hi Yinghai, >> >> Yinghai Lu wrote: >>> Analyze "console=uart8250,io,0x3f8,115200n8" in >>> i386_start_kernel/x86_64_start_kernel, >>> and call setup_early_serial8250_console() to init early serial console. >>> >>> only can handle io port kind of 8250. because mmio need ioremap. >>> >>> Signed-off-by: Yinghai Lu >> >> What's the purpose of this patch? Does it make my early boot I/O patch >> obsolete? >> >> Pekka > > No, they're complementary. Your patch serial-port enables the RM > kernel, whereas Yinghai pushes the initialization earlier in the PM kernel. yes. cover more range. Can you consider to ask Pekka to anaylze "console=uart8250,io, 0x3f8,115200n8" instead? it looks like we can remove "earlyprintk=ttyS0,115200", or "earlyprintk=serial" etc. earlycon=uart8250 or console=uart8250 should be better than earlyprintk. because it is shared between different archs already. > > Incidentally, Yinghai: it would be possible to push even an MMIO > reference earlier by reserving a fixmap slot for the early console. I'm > not sure if it's worth it, though. in setup_arch() for x86, now we have /* VMI may relocate the fixmap; do this before touching ioremap area */ vmi_init(); /* OFW also may relocate the fixmap */ olpc_ofw_detect(); early_trap_init(); early_cpu_init(); early_ioremap_init() so may need to move these vmi_init() olpc_ofw_detect() early_ioremap_init() to i386_start_kernel(), x86_start_kernel() may be not worth it at this time, could do that later if needed. Thanks Yinghai -- 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/