From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753429AbdFPJrL (ORCPT ); Fri, 16 Jun 2017 05:47:11 -0400 Received: from mail-wr0-f177.google.com ([209.85.128.177]:35389 "EHLO mail-wr0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753060AbdFPJrK (ORCPT ); Fri, 16 Jun 2017 05:47:10 -0400 MIME-Version: 1.0 In-Reply-To: <20170616075220.GV5248@pali> References: <20170616073539.1185-1-kai.heng.feng@canonical.com> <20170616075220.GV5248@pali> From: Kai-Heng Feng Date: Fri, 16 Jun 2017 17:46:58 +0800 Message-ID: Subject: Re: [PATCH] platform/x86: dell-laptop: Fix bogus keyboard backlight sysfs interface To: =?UTF-8?Q?Pali_Roh=C3=A1r?= Cc: mjg59@srcf.ucam.org, dvhart@infradead.org, platform-driver-x86@vger.kernel.org, LKML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id v5G9lMot005967 On Fri, Jun 16, 2017 at 3:52 PM, Pali Rohár wrote: > Should not this check to be rather: > > (kbd_token_bits != 0 && (kbd_token_bits & BIT(KBD_LED_OFF_TOKEN)) != BIT(KBD_LED_OFF_TOKEN)) > > To express that we have at least one token at it is different from > KBD_LED_OFF_TOKEN token? Yes, this expresses the intention more clearly. I'll use it instead. > >> kbd_led_present = true; >> } >> > > And more important, there are three ways how to control keyboard > backlight level: > > 1) Via SMBIOS token > 2) Via SMBIOS call 4/11/0x2 (arg2, byte0) > 3) Via SMBIOS call 4/11/0x2 (arg3, byte2) > > You are adding special case when only one SMBIOS toekn OFF is present > which belongs to 1). > > Therefore there should be same check for 2) and 3) that there are more > the one option to set... I am not familiar with SMBIOS call. Can you point out where 2) and 3) functions are? > > -- > Pali Rohár > pali.rohar@gmail.com