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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 21880C6778A for ; Sun, 1 Jul 2018 16:37:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D370925330 for ; Sun, 1 Jul 2018 16:37:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D370925330 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org 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 S1031459AbeGAQhh (ORCPT ); Sun, 1 Jul 2018 12:37:37 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36270 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031397AbeGAQh1 (ORCPT ); Sun, 1 Jul 2018 12:37:27 -0400 Received: from localhost (LFbn-1-12247-202.w90-92.abo.wanadoo.fr [90.92.61.202]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 5735FACD; Sun, 1 Jul 2018 16:37:26 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Waldemar Rymarkiewicz , Viresh Kumar Subject: [PATCH 4.17 022/220] PM / OPP: Update voltage in case freq == old_freq Date: Sun, 1 Jul 2018 18:20:46 +0200 Message-Id: <20180701160909.276606362@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180701160908.272447118@linuxfoundation.org> References: <20180701160908.272447118@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 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 4.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Waldemar Rymarkiewicz commit c5c2a97b3ac7d1ec19e7cff9e38caca6afefc3de upstream. 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 Fixes: 6a0712f6f199 ("PM / OPP: Add dev_pm_opp_set_rate()") Cc: 4.6+ # v4.6+ Signed-off-by: Waldemar Rymarkiewicz Signed-off-by: Viresh Kumar Signed-off-by: Greg Kroah-Hartman --- drivers/opp/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/opp/core.c +++ b/drivers/opp/core.c @@ -591,7 +591,7 @@ static int _generic_set_opp_regulator(co } /* 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;