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 D581EC4741F for ; Mon, 9 Nov 2020 09:53:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 825162067B for ; Mon, 9 Nov 2020 09:53:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fnarfbargle.com header.i=@fnarfbargle.com header.b="gHn8lIKN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729150AbgKIJxY (ORCPT ); Mon, 9 Nov 2020 04:53:24 -0500 Received: from ns3.fnarfbargle.com ([103.4.19.87]:43444 "EHLO ns3.fnarfbargle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726482AbgKIJxY (ORCPT ); Mon, 9 Nov 2020 04:53:24 -0500 Received: from srv.home ([10.8.0.1] ident=heh28988) by ns3.fnarfbargle.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.84_2) (envelope-from ) id 1kc3pn-000288-Sx; Mon, 09 Nov 2020 17:51:35 +0800 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=fnarfbargle.com; s=mail; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject; bh=TtsjbntIcMpX2KsPaJ72LQzb7aN1Qcl5TJzqivd2c78=; b=gHn8lIKNMeuQvdSu2z6TmxCbp5pkqkAKAenXHH6QZ/EOcn8DCZzn0dsj0TqP4L6TtT/JLlRbtEULVOz9wwIEvAOBRxTyHtnJRKNjfUXjwZ2Yp9WvaLOHYDMYTvPOzbvBU4X+xYF1e1VaX7MiKfxf1L2cyfxAnTe9mPoTVVY1BhE=; Subject: Re: [PATCH v3] applesmc: Re-work SMC comms To: Andreas Kemnade , Henrik Rydberg Cc: Arnd Bergmann , linux-hwmon@vger.kernel.org, "linux-kernel@vger.kernel.org" , hns@goldelico.com, Guenter Roeck , Jean Delvare 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> <20201109094424.1c10651f@aktux> From: Brad Campbell Message-ID: Date: Mon, 9 Nov 2020 20:51:32 +1100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.2.2 MIME-Version: 1.0 In-Reply-To: <20201109094424.1c10651f@aktux> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/11/20 7:44 pm, Andreas Kemnade wrote: > 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) Much appreciated Andreas. Regards, Brad