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=-8.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 3BC44C2D0A3 for ; Mon, 9 Nov 2020 08:44:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D0458206ED for ; Mon, 9 Nov 2020 08:44:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kemnade.info header.i=@kemnade.info header.b="Dt4afT0z" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729745AbgKIIoe (ORCPT ); Mon, 9 Nov 2020 03:44:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37320 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729730AbgKIIoe (ORCPT ); Mon, 9 Nov 2020 03:44:34 -0500 Received: from mail.andi.de1.cc (mail.andi.de1.cc [IPv6:2a01:238:4321:8900:456f:ecd6:43e:202c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3CD80C0613CF; Mon, 9 Nov 2020 00:44:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=kemnade.info; s=20180802; h=Content-Transfer-Encoding:Content-Type: MIME-Version:References:In-Reply-To:Message-ID:Subject:Cc:To:From:Date:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=TzAYk+oLfVC+xVZW8MM6v2hBnX5j/D5hCWL6Cocma5o=; b=Dt4afT0z6eA27cnX+8KRhbMcrn 29om7M2uPWubzw18vMW7SHfQwjicrvhjDvY+Ez+XvS+hyyWqy8n8jRGptzGAajg5ylxKGRw5aNIJ0 e/Y1Rd44uXpCKW7i6+fg/LsUwsCATVPJsbZuRcIGbVeNg170AZnX0e7jwJz0SwR+oivA=; Received: from p200300ccff0815001a3da2fffebfd33a.dip0.t-ipconnect.de ([2003:cc:ff08:1500:1a3d:a2ff:febf:d33a] helo=aktux) by mail.andi.de1.cc with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1kc2mn-0008R6-8n; Mon, 09 Nov 2020 09:44:25 +0100 Date: Mon, 9 Nov 2020 09:44:24 +0100 From: Andreas Kemnade To: Henrik Rydberg Cc: Brad Campbell , Arnd Bergmann , linux-hwmon@vger.kernel.org, "linux-kernel@vger.kernel.org" , hns@goldelico.com, Guenter Roeck , Jean Delvare Subject: Re: [PATCH v3] applesmc: Re-work SMC comms Message-ID: <20201109094424.1c10651f@aktux> In-Reply-To: <20201108101429.GA28460@mars.bitmath.org> References: <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> <41909045-9486-78d9-76c2-73b99a901b83@bitmath.org> <20201108101429.GA28460@mars.bitmath.org> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org On Sun, 8 Nov 2020 11:14:29 +0100 Henrik Rydberg wrote: > On Sun, Nov 08, 2020 at 09:35:28AM +0100, Henrik Rydberg wrote: > > Hi Brad, > > > > On 2020-11-08 02:00, Brad Campbell wrote: > > > G'day Henrik, > > > > > > I noticed you'd also loosened up the requirement for SMC_STATUS_BUSY in read_smc(). I assume > > > that causes problems on the early Macbook. This is revised on the one sent earlier. > > > If you could test this on your Air1,1 it'd be appreciated. > > > > No, I managed to screw up the patch; you can see that I carefully added the > > same treatment for the read argument, being unsure if the BUSY state would > > remain during the AVAILABLE data phase. I can check that again, but > > unfortunately the patch in this email shows the same problem. > > > > I think it may be worthwhile to rethink the behavior of wait_status() here. > > If one machine shows no change after a certain status bit change, then > > perhaps the others share that behavior, and we are waiting in vain. Just > > imagine how many years of cpu that is, combined. ;-) > > Here is a modification along that line. > > Compared to your latest version, this one has wait_status() return the > actual status on success. Instead of waiting for BUSY, it waits for > the other status bits, and checks BUSY afterwards. So as not to wait > unneccesarily, the udelay() is placed together with the single > outb(). The return value of send_byte_data() is augmented with > -EAGAIN, which is then used in send_command() to create the resend > loop. > > I reach 41 reads per second on the MBA1,1 with this version, which is > getting close to the performance prior to the problems. > > From b4405457f4ba07cff7b7e4f48c47668bee176a25 Mon Sep 17 00:00:00 2001 > From: Brad Campbell > Date: Sun, 8 Nov 2020 12:00:03 +1100 > Subject: [PATCH] hwmon: (applesmc) Re-work SMC comms > > 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. > > 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 : Inital attempt > v2 : Address logic and coding style > v3 : Removed some debug hangover. Added tested-by. Modifications for MacBookAir1,1 > v4 : Do not expect busy state to appear without other state changes > still works here (MacBookAir6,2) Regards, Andreas