Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751953AbdF1PvW (ORCPT ); Wed, 28 Jun 2017 11:51:22 -0400 Received: from merlin.infradead.org ([205.233.59.134]:59996 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751684AbdF1PvM (ORCPT ); Wed, 28 Jun 2017 11:51:12 -0400 Subject: Re: [RFC 3/5] drivers: boot_constraint: Add boot_constraints_disable kernel parameter To: Viresh Kumar , Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Rafael Wysocki , Vincent Guittot , Stephen Boyd , Mark Brown , Shiraz Hashim , Rob Herring , rnayak@codeaurora.org, linux-doc@vger.kernel.org References: From: Randy Dunlap Message-ID: <04d6732a-3a2e-2f04-1d6e-a4ac51470db5@infradead.org> Date: Wed, 28 Jun 2017 08:51:10 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1449 Lines: 37 On 06/28/2017 03:26 AM, Viresh Kumar wrote: > Users must be given an option to discard any constraints set by > bootloaders. For example, consider that a constraint is set for the LCD > controller's supply and the LCD driver isn't loaded by the kernel. If > the user doesn't need to use the LCD device, then he shouldn't be forced > to honour the constraint. > > We can also think about finer control of such constraints with help of > some sysfs files, but a kernel parameter is fine to begin with. > > Signed-off-by: Viresh Kumar > --- > Documentation/admin-guide/kernel-parameters.txt | 2 ++ > drivers/base/boot_constraint.c | 17 +++++++++++++++++ > 2 files changed, 19 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 7737ab5d04b2..35e8a298bfc1 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -426,6 +426,8 @@ > embedded devices based on command line input. > See Documentation/block/cmdline-partition.txt > > + boot_constraints_disable = Do not set any boot constraints for devices. > + No '=' sign. That is only used when there is a following parameter value. > boot_delay= Milliseconds to delay each printk during boot. > Values larger than 10 seconds (10000) are changed to > no delay (0). -- ~Randy