Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755233AbdCQAyC (ORCPT ); Thu, 16 Mar 2017 20:54:02 -0400 Received: from hera.aquilenet.fr ([141.255.128.1]:48640 "EHLO hera.aquilenet.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753522AbdCQAx7 (ORCPT ); Thu, 16 Mar 2017 20:53:59 -0400 Date: Fri, 17 Mar 2017 01:53:55 +0100 From: Samuel Thibault To: Aleksey Makarov Cc: linux-serial@vger.kernel.org, Petr Mladek , Steven Rostedt , Joe Perches , linux-kernel@vger.kernel.org Subject: Re: Does braille console work? Message-ID: <20170317005355.xwym3zpamym3rwp6@var.youpi.perso.aquilenet.fr> Mail-Followup-To: Samuel Thibault , Aleksey Makarov , linux-serial@vger.kernel.org, Petr Mladek , Steven Rostedt , Joe Perches , linux-kernel@vger.kernel.org References: <1bb67bee-b8f9-2835-725a-f36fda085216@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1bb67bee-b8f9-2835-725a-f36fda085216@linaro.org> Organization: I am not organized User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1295 Lines: 37 Hello, Aleksey Makarov, on jeu. 16 mars 2017 17:02:53 +0300, wrote: > There can be 3 outcomes from this function: > 1) it returns NULL and does not set brl_options > 2) it returns NULL and set the variable pointed by str to NULL > 3) it returns non-NULL Uh, that's odd indeed, the intent was that it'd return an error code only. > To register a braille console (i. e. to call __add_preferred_console() > with non-NULL brl_options) function _braille_console_setup() should > return NULL and initialize brl_options. return 0 (as in no error), actually, in the intent. > 1) in this case brl_options is NULL and non-braille console is registered > 2) kernel produces oops later in console_setup(). I reproduced it > passing "console=brl=aaa" parameter to kernel, see below. > 3) no console is registered > > So braille console registration should not work. What do I miss? Nothing, the code transformation was broken :/ > So it looks like braille console has not been used for more than 3 years. > Should we remote it? Please, no :) It is indeed not often useful, since one would usually use a userland daemon to access the system, but when one's system does not boot properly or something similar, it's useful to have the braille console. That's just very not often useful. Samuel