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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 B8B6EC2BA19 for ; Sun, 5 Apr 2020 22:51:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8495920672 for ; Sun, 5 Apr 2020 22:51:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586127109; bh=+qkpE/VzZVJjNYp14D0CGe0j5+UI5EbcqBZ0isMWYz0=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=c8wYAQBowQoAgIX+gHSdGkcuOdsaZGQBYiHYw0m4pQ4KK012idX5EW2xZxXs27Iew Eo/zOnYSTEdRgHSDLaUW8Wz/Rw/EP0f4kGc305GAlWTqgJy5Q8+MAoqWcZHpExq9GW hb6JxtrPVJULXZ62X26Fa1sXChBOCZ8AakwbzP/g= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727841AbgDEWvn (ORCPT ); Sun, 5 Apr 2020 18:51:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:54940 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727254AbgDEWvm (ORCPT ); Sun, 5 Apr 2020 18:51:42 -0400 Received: from mail-wr1-f50.google.com (mail-wr1-f50.google.com [209.85.221.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EAAF7206F8 for ; Sun, 5 Apr 2020 22:51:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586127102; bh=+qkpE/VzZVJjNYp14D0CGe0j5+UI5EbcqBZ0isMWYz0=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=f7N8j9bTEuX2pG7W41IR6FqaiigUcXyvSGQ66YOVJA02bYSkh6emWYqiN4GluXnBm sO7A1MZJJpNwgiFW/AV4zpbaScDAR/kEqwGHOAJzBqArfyuiGi9RTiwfzU0y0NNwFz 7uWbIv7/7cx76niUT/3fD8KvowuBbWTTSAtl05e0= Received: by mail-wr1-f50.google.com with SMTP id k1so5788266wrm.3 for ; Sun, 05 Apr 2020 15:51:41 -0700 (PDT) X-Gm-Message-State: AGi0PuZPN5BmZot42mnAmkjMivNiA0dva7QmTeLlhKDsYYy2AfGZnAyJ wUlaFl9VUa0fybu7VrfrtPMFlvgoD0pCis11pCFmow== X-Google-Smtp-Source: APiQypIZZeGyy9AWnrPYhspWabgLmcetsyynlVwx/fKVCTu+hT5tJ8/0bFBFj8nmq1k3Wvg5vUMIUVBAH8TL7+FgBpw= X-Received: by 2002:adf:aad7:: with SMTP id i23mr20451094wrc.184.1586127100363; Sun, 05 Apr 2020 15:51:40 -0700 (PDT) MIME-Version: 1.0 References: <1582498270-50674-1-git-send-email-schaecsn@gmx.net> <20200405180510.GD6313@kunai> <20200405214059.91F97899799@corona.crabdance.com> In-Reply-To: <20200405214059.91F97899799@corona.crabdance.com> From: Andy Lutomirski Date: Sun, 5 Apr 2020 15:51:29 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 0/1] i2c: imc: Add support for Intel iMC SMBus host controller. To: Stefan Schaeckeler Cc: Wolfram Sang , Andrew Lutomirski , linux-i2c@vger.kernel.org, LKML , Andy Shevchenko Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Apr 5, 2020 at 2:41 PM Stefan Schaeckeler wrote: > > Hello Wolfram, > > > > > This patch is based on Andy Lutomirski's iMC SMBus driver patch-set > > > > https://lkml.org/lkml/2016/4/28/926. It never made it into the kernel. I hope > > > > this rewrite will: > > > > > > > > > > > > Overview > > > > > > > > Modern Intel memory controllers host an SMBus controller and connection to > > > > DIMMs and their thermal sensors. The memory controller firmware has three modes > > > > of operation: Closed Loop Thermal Throttling (CLTT), Open Loop Thermal > > > > Throttling (OLTT) and none. > > > > > > > > - CLTT: The memory controller firmware is periodically accessing the DIMM > > > > temperature sensor over the SMBus. > > > > > > > > > > > > > I think this is great! One question, though: what happens if the > > > system is in CLTT mode but you disable CLTT and claim the bus for too > > > long? For example, if there's an infinite loop or other lockup which > > > you have the tsod polling interval set to 0? Does the system catch > > > fire or does the system do something intelligent like temporarily > > > switching to open loop? > > > > Any news on this question? > > Thank you for your interest in this patch. You can read my reply here > https://lkml.org/lkml/2020/3/1/216 I think it could make sense to upstream this driver but to require a scary boot-time option to enable it. Maybe i2c_imc.dangerous=1? > > Stefan