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=-0.5 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id 99422C07D5C for ; Thu, 14 Jun 2018 13:56:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4E8CF208DA for ; Thu, 14 Jun 2018 13:56:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4E8CF208DA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936060AbeFNN4k (ORCPT ); Thu, 14 Jun 2018 09:56:40 -0400 Received: from mga05.intel.com ([192.55.52.43]:55499 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755208AbeFNN4j (ORCPT ); Thu, 14 Jun 2018 09:56:39 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Jun 2018 06:56:39 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,222,1526367600"; d="scan'208";a="63152194" Received: from mucrsa0015.imu.intel.com ([10.62.163.98]) by fmsmga004.fm.intel.com with ESMTP; 14 Jun 2018 06:56:37 -0700 From: Waldemar Rymarkiewicz To: Viresh Kumar , Nishanth Menon , Stephen Boyd Cc: Waldemar Rymarkiewicz , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] PM / OPP: Update voltage in case freq == old_freq Date: Thu, 14 Jun 2018 15:56:08 +0200 Message-Id: <20180614135609.20574-1-waldemar.rymarkiewicz@gmail.com> X-Mailer: git-send-email 2.10.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This commit fixes a rare but possible case when the clk rate is updated without update of the regulator voltage. At boot up, CPUfreq checks if the system is running at the right freq. This is a sanity check in case a bootloader set clk rate that is outside of freq table present with cpufreq core. In such cases system can be unstable so better to change it to a freq that is preset in freq-table. The CPUfreq takes next freq that is >= policy->cur and this is our target_freq that needs to be set now. dev_pm_opp_set_rate(dev, target_freq) checks the target_freq and the old_freq (a current rate). If these are equal it returns early. If not, it searches for OPP (old_opp) that fits best to old_freq (not listed in the table) and updates old_freq (!). Here, we can end up with old_freq = old_opp.rate = target_freq, which is not handled in _generic_set_opp_regulator(). It's supposed to update voltage only when freq > old_freq || freq > old_freq. if (freq > old_freq) { ret = _set_opp_voltage(dev, reg, new_supply); [...] if (freq < old_freq) { ret = _set_opp_voltage(dev, reg, new_supply); if (ret) It results in, no voltage update while clk rate is updated. Example: freq-table = { 1000MHz 1.15V 666MHZ 1.10V 333MHz 1.05V } boot-up-freq = 800MHz # not listed in freq-table freq = target_freq = 1GHz old_freq = 800Mhz old_opp = _find_freq_ceil(opp_table, &old_freq); #(old_freq is modified!) old_freq = 1GHz Signed-off-by: Waldemar Rymarkiewicz --- drivers/opp/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/opp/core.c b/drivers/opp/core.c index ab2f3fe..31ff03d 100644 --- a/drivers/opp/core.c +++ b/drivers/opp/core.c @@ -598,7 +598,7 @@ static int _generic_set_opp_regulator(const struct opp_table *opp_table, } /* Scaling up? Scale voltage before frequency */ - if (freq > old_freq) { + if (freq >= old_freq) { ret = _set_opp_voltage(dev, reg, new_supply); if (ret) goto restore_voltage; -- 2.10.1