Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756719AbXEUE3a (ORCPT ); Mon, 21 May 2007 00:29:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753191AbXEUE3W (ORCPT ); Mon, 21 May 2007 00:29:22 -0400 Received: from nz-out-0506.google.com ([64.233.162.233]:5441 "EHLO nz-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752864AbXEUE3V (ORCPT ); Mon, 21 May 2007 00:29:21 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=eA0np/SmcdEJqKGpX7M7/rVYyY0rZ7JU3QtXeuLT29LwR8rsWDtV2FxnUkraWb0JdXIUEthLaNEcpkjXmZTbDiZSWZnTRn5skmAA0TO6GL1ZSOpQD6cihONMjXm1R8jbGtk94uhEPwvkjJM1qZTHcXO1U1myib9YqNHcx6rbii8= Message-ID: <86802c440705202129o6fe9fb89l47aef78e973c36c5@mail.gmail.com> Date: Sun, 20 May 2007 21:29:20 -0700 From: "Yinghai Lu" To: "Andrew Morton" , "Eric W. Biederman" Subject: Re: [PATCH]serial: make early_uart to use early_prarm instead of console_initcall Cc: "Bjorn Helgaas" , "Gerd Hoffmann" , "Andi Kleen" , "Linus Torvalds" , "linux kernel mailing list" In-Reply-To: <20070520202332.145d93a6.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200705181900.17101.yinghai.lu@sun.com> <20070520202332.145d93a6.akpm@linux-foundation.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2014 Lines: 53 On 5/20/07, Andrew Morton wrote: > I'll queue this up for some testing, but I'd be a bit reluctant to send it > into Linus due to my poor understanding of what it actually does. What > _is_ an early console, and how does it differ from a non-early one? > > Someone help, please. > > Coudl you please provide a patch against > Documentation/kernel-parameters.txt as well? > the story: Bjorn refer to andi's early_printk to create one early_uart. it took console=uart,io,0x3f8,9600n8 or console=uart,mem,0xfxxx,115200n8. and it is called via console_init. --- it is not really early uart for platform other than ia64. ia64 call early_serial_console_init explicitly, so it is some early. but it needs to late_initcall to do console switch. Gerd's patch (console handover) was merged into mainline. it will switch from early_printk to normal console in register_console via CON_BOOT flags.. ===> only for x86 I produced one patch to change early_uart calling from console_init to early_param. So to make early_uart to real early_uart for all other platform in addition to ia64. it will take earlycon=uart,io,0x3f8,9600n8 console=ttyS0,9600n8 but Bjorn said that don't let the customer to key two times about console command line. Then come this patch. will take earlycon=uart,io,0x3f8,9600n8 and it will switch to console ttyS0 automatically. ---- by calling add_preferred_console. Still need Bjorn to: 1. remove early_serial_console_init call in ia64 setup_arch. 2. verify mem io 8250 compatiable card. for 2, in x86 platform we need to use fix_to_virt and fix map to give it one fixed virtual address. == like Eric did for usb debug port console. I will send out another in email about updated early dbgp console with current tree. YH - 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/