From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: console vs earlycon ? Date: Thu, 22 Oct 2015 00:54:28 +0200 Message-ID: <4134303.BAT7dSJRN3@wuerfel> References: <3890353.0icCv0Zeuq@wuerfel> <5627E679.1050207@hurleysoftware.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <5627E679.1050207@hurleysoftware.com> Sender: linux-kernel-owner@vger.kernel.org To: linux-arm-kernel@lists.infradead.org Cc: Peter Hurley , Masahiro Yamada , Linux Kernel Mailing List , Stefan Agner , linux-serial@vger.kernel.org List-Id: linux-serial@vger.kernel.org On Wednesday 21 October 2015 15:24:41 Peter Hurley wrote: > On 10/21/2015 03:00 PM, Arnd Bergmann wrote: > > 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. > > I assume you mean the hacks necessary to get _earlycon_ working at > console_init() time, because the hacks necessary to get non-8250 > serial consoles working at console_init() would be extensive and > brand new. > No, I was just being slow and assumed that the 51 drivers that come with a console_initcall() do something in there to actually start the console, but you are right that most of them don't actually do that. They just call register_console() and wait for the device to show up later. Arnd