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 X-Spam-Level: X-Spam-Status: No, score=-3.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7BBC9C433DF for ; Thu, 27 Aug 2020 20:18:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4FC762084C for ; Thu, 27 Aug 2020 20:18:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="DIOK9W1Y" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726802AbgH0USk (ORCPT ); Thu, 27 Aug 2020 16:18:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56366 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726120AbgH0USk (ORCPT ); Thu, 27 Aug 2020 16:18:40 -0400 Received: from mail-pj1-x1043.google.com (mail-pj1-x1043.google.com [IPv6:2607:f8b0:4864:20::1043]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D935BC061264; Thu, 27 Aug 2020 13:18:39 -0700 (PDT) Received: by mail-pj1-x1043.google.com with SMTP id n3so3120170pjq.1; Thu, 27 Aug 2020 13:18:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=jJ9ggPa2XTFO0SYWdRumNSBhXW77Wne8Cizbx4794JM=; b=DIOK9W1Y7b9ZT9pVs3Oo73huYt7MWVdhKX1PqA3heiz1xKWJF4LN4CpTV/NPhgOULo KFFvnvlAWdwwXYv4QP7rT/38SlEVDLd9Z2FsQwWKWRETBmLYaXS4FtOCPTMX4gWl6DKd sf2ahAmosVW7xJAzQxo5IUYRX1PJLAxHb6bOf8ayR5bhVOszh1LRUlTKhTo4bMxEeLMW FPdW/NUDSmCfMYFX/+Qt4sTHEhdsVcmKip9k3G3d8FIDlWiBIfr0omio7cTInSWP0ZWT PC4EhOBVGuWXJBdkBBP98gZYxnzUI9SXmHznDCV17Anrolo3n+XFT4zIKqPUIG7cZlSd 7T4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=jJ9ggPa2XTFO0SYWdRumNSBhXW77Wne8Cizbx4794JM=; b=Yx1C/KMBaUR5iNLCq0Kc4AEMkUqOkV7bbQ8ZqdOWwfO235yseq80FcrM7ddyHZhBfB Vp2re812IdxAXKuQwzLHQx2Dx0v8EAcyMT8eZ70tKAZoy31Q8o31yxjZxAoJXcfXSe2E jdX1vhQ2FhEDGPUNooFB2HiP69u+cHX3SPfEJ8hVYxNjkcF5JjLcXifw3AWOyQJlYKCM 5hWaOTXPvakhcVx68YCRLOiBSkHswQUWtGS9i0C9sajFNzmDI91WieZw42GMuH6/geNk yt9spLf9/fdyTn+/HLN0h0ilHH8RD0s/WPZlXQaexN0W6XK7C02h9lVHzW9ZqNRXiGdf lyUQ== X-Gm-Message-State: AOAM532R8VCk4u8H49Ab29vWsh7CUFmc7uZbhDBf+EVbMg2EVM05w5YF Os+ii49feqIhTndWX4mZiDv2Q7kX0kqKVl4kgcZGTy7gBhdWTA== X-Google-Smtp-Source: ABdhPJyG0xnrG1CdLhtmiiW/DFCoU8s0Jkonrgv2RvIG4he9l0TkUPlw8tGMVnByc4xARDIBNnA+sVDgOhJO2J4nuA8= X-Received: by 2002:a17:90b:509:: with SMTP id r9mr512560pjz.228.1598559519457; Thu, 27 Aug 2020 13:18:39 -0700 (PDT) MIME-Version: 1.0 References: <20200827135205.1.I6981f9a9f0c12e60f8038f3b574184f8ffc1b9b5@changeid> In-Reply-To: From: Andy Shevchenko Date: Thu, 27 Aug 2020 23:18:23 +0300 Message-ID: Subject: Re: [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands To: Raul E Rangel Cc: linux-input , Dmitry Torokhov , "S, Shirish" , Andy Shevchenko , Dan Murphy , Darren Hart , Jacek Anaszewski , "Lee, Chun-Yi" , Pavel Machek , Rajat Jain , Stephen Boyd , Linux Kernel Mailing List , Linux LED Subsystem , Platform Driver Content-Type: text/plain; charset="UTF-8" Sender: linux-input-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org On Thu, Aug 27, 2020 at 11:12 PM Andy Shevchenko wrote: > On Thu, Aug 27, 2020 at 10:52 PM Raul E Rangel wrote: ... > > + mutex_lock(&i8042_mutex); > > + > > spin_lock_irqsave(&i8042_lock, flags); > > retval = __i8042_command(param, command); > > spin_unlock_irqrestore(&i8042_lock, flags); > > > > + mutex_unlock(&i8042_mutex); > > Question 1. Why do you need mutex at all in the above situation? Spin > lock isn't enough? > > ... > > > - i8042_lock_chip(); > > - > > if (value == LED_OFF) > > i8042_command(NULL, CLEVO_MAIL_LED_OFF); > > else if (value <= LED_HALF) > > i8042_command(NULL, CLEVO_MAIL_LED_BLINK_0_5HZ); > > else > > i8042_command(NULL, CLEVO_MAIL_LED_BLINK_1HZ); > > - > > - i8042_unlock_chip(); > > - > > Now, these three commands are not considered as a transaction (no > atomicity). That's why your patch is wrong. Ah, I didn't pay attention that this is one command call. But still Q1 is valid. -- With Best Regards, Andy Shevchenko