From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B061C433F5 for ; Mon, 25 Oct 2021 12:03:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 29C6460F22 for ; Mon, 25 Oct 2021 12:03:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231925AbhJYMFz (ORCPT ); Mon, 25 Oct 2021 08:05:55 -0400 Received: from mga14.intel.com ([192.55.52.115]:24240 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231133AbhJYMFv (ORCPT ); Mon, 25 Oct 2021 08:05:51 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10147"; a="229903341" X-IronPort-AV: E=Sophos;i="5.87,180,1631602800"; d="scan'208";a="229903341" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Oct 2021 05:03:28 -0700 X-IronPort-AV: E=Sophos;i="5.87,180,1631602800"; d="scan'208";a="446201127" Received: from smile.fi.intel.com ([10.237.72.184]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Oct 2021 05:03:27 -0700 Received: from andy by smile.fi.intel.com with local (Exim 4.95) (envelope-from ) id 1meyh0-000c18-2u; Mon, 25 Oct 2021 15:03:06 +0300 Date: Mon, 25 Oct 2021 15:03:05 +0300 From: "andriy.shevchenko" To: "changlianzhi@uniontech.com" Cc: linux-kernel , "dmitry.torokhov" , gregkh , jirislaby , 282827961 <282827961@qq.com> Subject: Re: [PATCH v6] tty: Fix the keyboard led light display problem Message-ID: References: <20211021020511.18016-1-changlianzhi@uniontech.com> <202110250129181502896@uniontech.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202110250129181502896@uniontech.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 25, 2021 at 01:29:18AM +0800, changlianzhi@uniontech.com wrote: > >>On Thu, Oct 21, 2021 at 10:05:11AM +0800, lianzhi chang wrote: > >> Switching from the desktop environment to the tty environment, > >> the state of the keyboard led lights and the state of the keyboard > >> lock are inconsistent. This is because the attribute kb->kbdmode > >> of the tty bound in the desktop environment (xorg) is set to > >> VC_OFF, which causes the ledstate and kb->ledflagstate > >> values of the bound tty to always be 0, which causes the switch > >> from the desktop When to the tty environment, the LED light > >> status is inconsistent with the keyboard lock status. > > >... > > >> + unsigned long leds; > >> + > >> + leds = (unsigned long)ledstate; > > >Can be one line. > > >But most important question you are ignoring to answer / address is why do you > >use casting? > >>But most important question you are ignoring to answer / address is why do you > >>use casting? > Casting is used here because: > The second parameter of test_bit is "volatile unsigned long *addr" (see constant_test_bit() in /arch/x86/include/asm/bitops.h), but ledstate is an "unsigned int" type. If casting is not used, > compile Will report an error. Wait, you are casting pointer to an integer?! This is completely wrong in this case! -- With Best Regards, Andy Shevchenko