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=-8.4 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 3276CC56201 for ; Wed, 11 Nov 2020 20:05:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9CD192087D for ; Wed, 11 Nov 2020 20:05:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=bitmath.org header.i=@bitmath.org header.b="Hb6Pwf9C" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726046AbgKKUFy (ORCPT ); Wed, 11 Nov 2020 15:05:54 -0500 Received: from mailrelay1-2.pub.mailoutpod1-cph3.one.com ([46.30.212.0]:26211 "EHLO mailrelay1-2.pub.mailoutpod1-cph3.one.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725860AbgKKUFx (ORCPT ); Wed, 11 Nov 2020 15:05:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bitmath.org; s=20191106; h=content-transfer-encoding:content-type:in-reply-to:mime-version:date: message-id:from:references:cc:to:subject:from; bh=bLnllL/t03j3i5XoFNTbRyx56nqfkYo3HdLiGc5a8n8=; b=Hb6Pwf9CvYHxV+yIKLNEyp5qgkAeRp3GpPFRiD49GKF2hmpUN0qhS6L35KXfBkQnB3LvvWUo+SFku r6aPR9CHZ4LuiCcE1mFmoDypCP/r4fJKUdRWwQ0fgX8N52JuXb6oj34cnMg67PCkG1Yw/3dkBGztfm j1DkYpiUqmnR2iKEA2IueEwzDp886lZRXefHFCfLWHqK8R1lJTbwFczmZwQpz6sasuWGvaXn6S8ykj xalp/b6WsT7Tt4TXgfQyOsbshQ5S8NwxleagF+stvb7S80FQq904tdJz7S6gwhD9l7B2ULra+YjWl7 83eCIKCKPBF8jg7XqoxnF0NymdAviOg== X-HalOne-Cookie: eaabbb6561265111dafb1c10745e60b401987cdd X-HalOne-ID: 4ab3dac0-2459-11eb-965a-d0431ea8a283 Received: from [192.168.19.13] (h-155-4-128-97.na.cust.bahnhof.se [155.4.128.97]) by mailrelay1.pub.mailoutpod1-cph3.one.com (Halon) with ESMTPSA id 4ab3dac0-2459-11eb-965a-d0431ea8a283; Wed, 11 Nov 2020 20:05:49 +0000 (UTC) Subject: Re: [PATCH v5 1/1] applesmc: Re-work SMC comms To: Brad Campbell , linux-hwmon@vger.kernel.org Cc: Arnd Bergmann , "linux-kernel@vger.kernel.org" , hns@goldelico.com, Andreas Kemnade , Jean Delvare , Guenter Roeck References: <20200930105442.3f642f6c@aktux> <68467f1b-cea1-47ea-a4d4-8319214b072a@fnarfbargle.com> <20201104142057.62493c12@aktux> <2436afef-99c6-c352-936d-567bf553388c@fnarfbargle.com> <7a085650-2399-08c0-3c4d-6cd1fa28a365@roeck-us.net> <10027199-5d31-93e7-9bd8-7baaebff8b71@roeck-us.net> <70331f82-35a1-50bd-685d-0b06061dd213@fnarfbargle.com> <3c72ccc3-4de1-b5d0-423d-7b8c80991254@fnarfbargle.com> <6d071547-10ee-ca92-ec8b-4b5069d04501@bitmath.org> <8e117844-d62a-bcb1-398d-c59cc0d4b878@fnarfbargle.com> <9109d059-d9cb-7464-edba-3f42aa78ce92@bitmath.org> <5310c0ab-0f80-1f9e-8807-066223edae13@bitmath.org> <57057d07-d3a0-8713-8365-7b12ca222bae@fnarfbargle.com> <4eca09dc-7b32-767c-eab0-b9ad8b41efcc@fnarfbargle.com> <8c525b3b-b4a6-8ee4-8128-a20e0ad408e4@fnarfbargle.com> From: Henrik Rydberg Message-ID: <29b03865-f00a-f121-b7a5-c4b9179a27cb@bitmath.org> Date: Wed, 11 Nov 2020 21:05:59 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <8c525b3b-b4a6-8ee4-8128-a20e0ad408e4@fnarfbargle.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-11-11 14:06, Brad Campbell wrote: > Commit fff2d0f701e6 ("hwmon: (applesmc) avoid overlong udelay()") > introduced an issue whereby communication with the SMC became > unreliable with write errors like : > > [ 120.378614] applesmc: send_byte(0x00, 0x0300) fail: 0x40 > [ 120.378621] applesmc: LKSB: write data fail > [ 120.512782] applesmc: send_byte(0x00, 0x0300) fail: 0x40 > [ 120.512787] applesmc: LKSB: write data fail > > The original code appeared to be timing sensitive and was not reliable > with the timing changes in the aforementioned commit. > > This patch re-factors the SMC communication to remove the timing > dependencies and restore function with the changes previously > committed. Logic changes based on inspection of the Apple SMC kext. > > Tested on : MacbookAir6,2 MacBookPro11,1 iMac12,2, MacBookAir1,1, > MacBookAir3,1 > > Fixes: fff2d0f701e6 ("hwmon: (applesmc) avoid overlong udelay()") > Reported-by: Andreas Kemnade > Tested-by: Andreas Kemnade # MacBookAir6,2 > Acked-by: Arnd Bergmann > Signed-off-by: Brad Campbell > Signed-off-by: Henrik Rydberg > > --- > Changelog : > v1 : Initial attempt > v2 : Address logic and coding style > v3 : Removed some debug hangover. Added tested-by. Modifications for MacBookAir1,1 > v4 : Re-factored logic based on Apple driver. Simplified wait_status loop > v5 : Re-wrote status loop. Simplified busy check in send_byte(). Fixed formatting Hi Brad, This version is still working fine on the MBA1,1, at 50 reads per second. Thanks, Henrik