From patchwork Fri Sep 8 14:12:19 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Daniel Lezcano X-Patchwork-Id: 112092 Delivered-To: patch@linaro.org Received: by 10.37.128.210 with SMTP id c18csp1678801ybm; Fri, 8 Sep 2017 07:14:14 -0700 (PDT) X-Received: by 10.99.49.205 with SMTP id x196mr3306175pgx.121.1504880054423; Fri, 08 Sep 2017 07:14:14 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1504880054; cv=none; d=google.com; s=arc-20160816; b=yAJwGnHTsz21mtwTdu1Tq1BWCX7specjkahdRytYHddp8BQ3bXLoN8yqsD3iST1yGt q1H1YZyRkcxxZ4VdqYOoQKF+w1sSyOVW+1Ofd3uid4gJatSD8fuVCiUkUUef/BB1pDDU niGYuOjFgsDZTpiPAtvxSImdUngPb4XQ3XfzyyFONMt5W3uSb4IEAW9mqhqi8wssRE57 nuLo15YdsBFYk5y9JjIG/6tFu4OP0jq506CwWcecNJzeKcFEGG0hV/K8UNFb7SGhnBFQ nQSyMuGs/C5kTCAn18dsYZ3H+TqZGETndbKgWtVF0nilzPmUfclgdqUJTrn4Gxn8SZ1J yWcw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature:arc-authentication-results; bh=ZAA7cwvWIVhEfod0/pbDZLum93iflo7gN0aaE9f+s5w=; b=TXGU9jKtZkg9Tk367BDBmbPnDEAkujkW0g+qtqjoUczfZSpCQyJ9XDvLnbsmKW+UL4 uyQYuX8iYy3/HimBkNVecCQzOuipw0d+pdzqNFLl5IxqkytZ8Tyb/BA3F2YHn7ZZ+QQq OIRWAWZrFUFjO1yHjG2ZX5I8HAvBJvdHuQYLAsiT5B+7egH2WkCrliUW8QDbEuTlq0ko zs+5dSaO7mwCMqn3Lnwvfb/ne/voF9yXsg+vHBgHMX/iWSENGOOBgeYBjqt4ndJShncR QaoMn/O7cbKYAAGESjQS63Qjj2qH5RD8lqkUiKOsBOxh41zDEV/2GnK2xmvtPrAn/9tn T+jw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=fP11C1IH; spf=pass (google.com: best guess record for domain of linux-pm-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-pm-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id a24si1231604pfe.333.2017.09.08.07.14.13; Fri, 08 Sep 2017 07:14:14 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-pm-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=fP11C1IH; spf=pass (google.com: best guess record for domain of linux-pm-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-pm-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752017AbdIHOOM (ORCPT + 12 others); Fri, 8 Sep 2017 10:14:12 -0400 Received: from mail-wr0-f171.google.com ([209.85.128.171]:33248 "EHLO mail-wr0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755219AbdIHOOL (ORCPT ); Fri, 8 Sep 2017 10:14:11 -0400 Received: by mail-wr0-f171.google.com with SMTP id a43so4972381wrc.0 for ; Fri, 08 Sep 2017 07:14:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ZAA7cwvWIVhEfod0/pbDZLum93iflo7gN0aaE9f+s5w=; b=fP11C1IHTzCIqUKt8ggUjpz65qiA7BKrZTd4cAoDZBDz2NRs5LEFeUj42dQK9zjO5r 6Qn2N7oUwgwRBayIwBDIC7mldn5KnUnxGx5pxkVatU0JxrNpWS67LJU0J2Y0iVDF/IAD B0RC0XOBYSLVC7Ssi/iS9UB31zUa3B5cH2rQk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ZAA7cwvWIVhEfod0/pbDZLum93iflo7gN0aaE9f+s5w=; b=rRLbK64I5SKxtcXMhFAQukfk7LHZ2dP2tOEkFnFiMll/RltvDq/Ce9LHWREm/12twh yDray15mYUjhe+G4deT+/D2zmPugkVoGxSsdiJjwaoWpi9++ru8XMQNOnrUXuMhcQtqa aTyKB87wTlcUdFGNh0WNBLCeyoDc+TH4aYSjSOmNprM62taAdacrm7pxcmZZy6c2bp4Y /YB3LmLmjwGMGpfVNz2I4gXeedaWbalctNMTFoat72x2SL/0hAbLhuE+lutHuf0F6UBu I+tUP/dRvA0EhcazbeKbysUXKbC0tn4oVrKtGuDrwa2/nSf+1OBUnvLKhu+CHLHha2DM 7cBw== X-Gm-Message-State: AHPjjUgr7WdP0sX5PKLF4zlywuuYHJhZ5QFG42mJDzXv8QYIspDU0tWK VWPjkTOu5Tla/YP0 X-Google-Smtp-Source: ADKCNb6GS6nL9+lYMqSpDtXCbEQWVYlRlb/duJ7JNg7Rul+iO+s0NFRHY5ERdcnQAhCUxJCzc/x7dA== X-Received: by 10.223.185.123 with SMTP id b56mr2276904wrg.115.1504880049793; Fri, 08 Sep 2017 07:14:09 -0700 (PDT) Received: from localhost.localdomain ([2a01:e35:879a:6cd0:6426:ff85:17d6:f2f2]) by smtp.gmail.com with ESMTPSA id k9sm2594673wrk.27.2017.09.08.07.14.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 08 Sep 2017 07:14:09 -0700 (PDT) From: Daniel Lezcano To: rui.zhang@intel.com, edubezval@gmail.com Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, daniel.lezcano@linaro.org, Keerthy , John Stultz , Leo Yan Subject: [PATCH V3] thermal/drivers/step_wise: Fix temperature regulation misbehavior Date: Fri, 8 Sep 2017 16:12:19 +0200 Message-Id: <1504879940-11591-1-git-send-email-daniel.lezcano@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org There is a particular situation when the cooling device is cpufreq and the heat dissipation is not efficient enough where the temperature increases little by little until reaching the critical threshold and leading to a SoC reset. The behavior is reproducible on a hikey6220 with bad heat dissipation (eg. stacked with other boards). Running a simple C program doing while(1); for each CPU of the SoC makes the temperature to reach the passive regulation trip point and ends up to the maximum allowed temperature followed by a reset. This issue has been also reported by running the libhugetlbfs test suite. What is observed is a ping pong between two cpu frequencies, 1.2GHz and 900MHz while the temperature continues to grow. It appears the step wise governor calls get_target_state() the first time with the throttle set to true and the trend to 'raising'. The code selects logically the next state, so the cpu frequency decreases from 1.2GHz to 900MHz, so far so good. The temperature decreases immediately but still stays greater than the trip point, then get_target_state() is called again, this time with the throttle set to true *and* the trend to 'dropping'. From there the algorithm assumes we have to step down the state and the cpu frequency jumps back to 1.2GHz. But the temperature is still higher than the trip point, so get_target_state() is called with throttle=1 and trend='raising' again, we jump to 900MHz, then get_target_state() is called with throttle=1 and trend='dropping', we jump to 1.2GHz, etc ... but the temperature does not stabilizes and continues to increase. [ 237.922654] thermal thermal_zone0: Trip0[type=1,temp=65000]:trend=1,throttle=1 [ 237.922678] thermal thermal_zone0: Trip1[type=1,temp=75000]:trend=1,throttle=1 [ 237.922690] thermal cooling_device0: cur_state=0 [ 237.922701] thermal cooling_device0: old_target=0, target=1 [ 238.026656] thermal thermal_zone0: Trip0[type=1,temp=65000]:trend=2,throttle=1 [ 238.026680] thermal thermal_zone0: Trip1[type=1,temp=75000]:trend=2,throttle=1 [ 238.026694] thermal cooling_device0: cur_state=1 [ 238.026707] thermal cooling_device0: old_target=1, target=0 [ 238.134647] thermal thermal_zone0: Trip0[type=1,temp=65000]:trend=1,throttle=1 [ 238.134667] thermal thermal_zone0: Trip1[type=1,temp=75000]:trend=1,throttle=1 [ 238.134679] thermal cooling_device0: cur_state=0 [ 238.134690] thermal cooling_device0: old_target=0, target=1 In this situation the temperature continues to increase while the trend is oscillating between 'dropping' and 'raising'. We need to keep the current state untouched if the throttle is set, so the temperature can decrease or a higher state could be selected, thus preventing this oscillation. Keeping the next_target untouched when 'throttle' is true at 'dropping' time fixes the issue. The following traces show the governor does not change the next state if trend==2 (dropping) and throttle==1. [ 2306.127987] thermal thermal_zone0: Trip0[type=1,temp=65000]:trend=1,throttle=1 [ 2306.128009] thermal thermal_zone0: Trip1[type=1,temp=75000]:trend=1,throttle=1 [ 2306.128021] thermal cooling_device0: cur_state=0 [ 2306.128031] thermal cooling_device0: old_target=0, target=1 [ 2306.231991] thermal thermal_zone0: Trip0[type=1,temp=65000]:trend=2,throttle=1 [ 2306.232016] thermal thermal_zone0: Trip1[type=1,temp=75000]:trend=2,throttle=1 [ 2306.232030] thermal cooling_device0: cur_state=1 [ 2306.232042] thermal cooling_device0: old_target=1, target=1 [ 2306.335982] thermal thermal_zone0: Trip0[type=1,temp=65000]:trend=0,throttle=1 [ 2306.336006] thermal thermal_zone0: Trip1[type=1,temp=75000]:trend=0,throttle=1 [ 2306.336021] thermal cooling_device0: cur_state=1 [ 2306.336034] thermal cooling_device0: old_target=1, target=1 [ 2306.439984] thermal thermal_zone0: Trip0[type=1,temp=65000]:trend=2,throttle=1 [ 2306.440008] thermal thermal_zone0: Trip1[type=1,temp=75000]:trend=2,throttle=0 [ 2306.440022] thermal cooling_device0: cur_state=1 [ 2306.440034] thermal cooling_device0: old_target=1, target=0 [ ... ] After a while, if the temperature continues to increase, the next state becomes 2 which is 720MHz on the hikey. That results in the temperature stabilizing around the trip point. [ 2455.831982] thermal thermal_zone0: Trip0[type=1,temp=65000]:trend=1,throttle=1 [ 2455.832006] thermal thermal_zone0: Trip1[type=1,temp=75000]:trend=1,throttle=0 [ 2455.832019] thermal cooling_device0: cur_state=1 [ 2455.832032] thermal cooling_device0: old_target=1, target=1 [ 2455.935985] thermal thermal_zone0: Trip0[type=1,temp=65000]:trend=0,throttle=1 [ 2455.936013] thermal thermal_zone0: Trip1[type=1,temp=75000]:trend=0,throttle=0 [ 2455.936027] thermal cooling_device0: cur_state=1 [ 2455.936040] thermal cooling_device0: old_target=1, target=1 [ 2456.043984] thermal thermal_zone0: Trip0[type=1,temp=65000]:trend=0,throttle=1 [ 2456.044009] thermal thermal_zone0: Trip1[type=1,temp=75000]:trend=0,throttle=0 [ 2456.044023] thermal cooling_device0: cur_state=1 [ 2456.044036] thermal cooling_device0: old_target=1, target=1 [ 2456.148001] thermal thermal_zone0: Trip0[type=1,temp=65000]:trend=1,throttle=1 [ 2456.148028] thermal thermal_zone0: Trip1[type=1,temp=75000]:trend=1,throttle=1 [ 2456.148042] thermal cooling_device0: cur_state=1 [ 2456.148055] thermal cooling_device0: old_target=1, target=2 [ 2456.252009] thermal thermal_zone0: Trip0[type=1,temp=65000]:trend=2,throttle=1 [ 2456.252041] thermal thermal_zone0: Trip1[type=1,temp=75000]:trend=2,throttle=0 [ 2456.252058] thermal cooling_device0: cur_state=2 [ 2456.252075] thermal cooling_device0: old_target=2, target=1 IOW, this change is needed to keep the state for a cooling device if the temperature trend is oscillating while the temperature increases slightly. Without this change, the situation above leads to a catastrophic crash by a hardware reset on hikey. This issue has been reported to happen on an OMAP dra7xx also. Signed-off-by: Daniel Lezcano Cc: Keerthy Cc: John Stultz Cc: Leo Yan --- drivers/thermal/step_wise.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) -- 2.7.4 Tested-by: Keerthy Reviewed-by: Keerthy diff --git a/drivers/thermal/step_wise.c b/drivers/thermal/step_wise.c index be95826..ee047ca 100644 --- a/drivers/thermal/step_wise.c +++ b/drivers/thermal/step_wise.c @@ -31,8 +31,7 @@ * If the temperature is higher than a trip point, * a. if the trend is THERMAL_TREND_RAISING, use higher cooling * state for this trip point - * b. if the trend is THERMAL_TREND_DROPPING, use lower cooling - * state for this trip point + * b. if the trend is THERMAL_TREND_DROPPING, do nothing * c. if the trend is THERMAL_TREND_RAISE_FULL, use upper limit * for this trip point * d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit @@ -94,9 +93,11 @@ static unsigned long get_target_state(struct thermal_instance *instance, if (!throttle) next_target = THERMAL_NO_TARGET; } else { - next_target = cur_state - 1; - if (next_target > instance->upper) - next_target = instance->upper; + if (!throttle) { + next_target = cur_state - 1; + if (next_target > instance->upper) + next_target = instance->upper; + } } break; case THERMAL_TREND_DROP_FULL: