From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932183AbbJUTA7 (ORCPT ); Wed, 21 Oct 2015 15:00:59 -0400 Received: from mout.kundenserver.de ([212.227.126.131]:55370 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753938AbbJUTA4 (ORCPT ); Wed, 21 Oct 2015 15:00:56 -0400 From: Arnd Bergmann To: Peter Hurley Cc: Masahiro Yamada , Linux Kernel Mailing List , Stefan Agner , linux-serial@vger.kernel.org, linux-arm-kernel Subject: Re: console vs earlycon ? Date: Wed, 21 Oct 2015 21:00:24 +0200 Message-ID: <3890353.0icCv0Zeuq@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <5627AFFF.6060900@hurleysoftware.com> References: <4963882.HSXu6hF7zO@wuerfel> <5627AFFF.6060900@hurleysoftware.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:4lpfEwhhb+59Cgu8r7dCDlMO5N6BSAHAQXcYo1mJqST3aoZp+qz wYZeWbPD5hO3eiYTYyecwXrfP/pqJo8KSDAX1gA+pGucda3pQ3Q/XbOaDMmFXymvffGTMgX /Sa28x32cjmF9ekoe61Avk4GggICRhClK6BYMopLaJcNIOro0hOpMZt70xchztF76XfZjmY HlB4J5B7COdRL+6EFLEVw== X-UI-Out-Filterresults: notjunk:1;V01:K0:RtoCqCyQlUY=:2muYiqZXsLGZyA2UCAbpY7 5rTliixve0tvy/MV0hWa+s9y5wX1j1i2J44ZOZkVTc/PJzvFluuRrwliiKucSekJARz8xkoHL mImp0IgN8yHv97MJ3EhPjrU7mJ90IkgQ3Ogi4NHNE4RJLnsOQhm6EL3A3yI3kn7M0uIpQiXdm 4cPz9vYKn/ybxum7ywKytYtX3HC6QhntAabN6Sxwm1G3t5unIsm0Pvwz9/UFm5dkKq/PctqPB F707H1iffLRIG7mRJ7ldAre+2SUnW4G2HBBf6j0ibZf9r8aWHm35gAZE55eb4leea8K3JGiyB SkuhjnXZPuvtu0IU/D3/8gqS4VcYmOWwhd0uWfmFjD7UHAahgrvpfJeC7ObueE2cpiYuwM9Mi rpyCZuTFkgBh7+hg9v/MudCaj/JT4iV8G/lswsQ8aIjS/YA4E4McUFlQtRO6igLCYcQuMzNsT 5l0pCE4o8b+fO/WUhCIyIBtKhJ/6gYgcEm/9vNB+yrJqyOVsWyB9iDAdoTxOa5CJzgYOWkLtX eNGdzIlZi3UUKcLtELB5UAS0OfpLTBPvkXNPUyxujFgSVX2UN5GkjjFlg/VHZQKNoWVe6cQ8i FyMMx49ex4gd8+PdWQgtEIn8NMiUCWddc4bJvkJ8A9gsA0L7GByoMEflKs37Bcu9GHOtnc4lg wfTWNfd5ozuksAOXQFIVhxIAvYoEkcHd+77up2mVmTpCZC5B3TYEqWpk6lgvutUbOKivz8qeH yAfCUHVBSipfnfkI Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 21 October 2015 11:32:15 Peter Hurley wrote: > On 10/21/2015 10:13 AM, Arnd Bergmann wrote: > > On Wednesday 21 October 2015 09:53:47 Peter Hurley wrote: > > > > Ah, I had no idea we were moving in this direction. > > I would not say this was a conscious design decision, but rather an > outcome of getting-something-working-without-breaking-existing-usage. > > My main focus with earlycon/console has been to try to reduce and > generalize the existing code. Ok. > >> I'm assuming the issue with trying to get console_init() working > >> is because the dummy color console causes the earlycon to be disabled? > > > > I don't think so. > > > > My line of thinking was more about usability: earlycon requires that > > you edit the kernel command line at the moment, while console_init() > > doesn't require any user interaction and just uses the stdout-path. > > > > I guess we could enable earlycon using a Kconfig symbol if we want > > to, or make it a per-architecture decision whether it's enabled even > > in the absence of the command line flag. > > Ah, I see. You want to start the stdout-path console at console_init() > time. Yes, I see this as a tradeoff: we want the console to be as early as possible in order to report boot-time errors to the user, but not so early to require hacks that can cause problems themselves. earlycon has to do some scary stuff and is relatively recent, while the hacks necessary for console_init() are much older and better tested. Arnd