From patchwork Mon Nov 25 04:23:59 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Viresh Kumar X-Patchwork-Id: 3228021 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 4D8C2C045B for ; Mon, 25 Nov 2013 04:24:38 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 4CB2820256 for ; Mon, 25 Nov 2013 04:24:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5EB6E20253 for ; Mon, 25 Nov 2013 04:24:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753176Ab3KYEYH (ORCPT ); Sun, 24 Nov 2013 23:24:07 -0500 Received: from mail-qe0-f47.google.com ([209.85.128.47]:65466 "EHLO mail-qe0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752180Ab3KYEYG (ORCPT ); Sun, 24 Nov 2013 23:24:06 -0500 Received: by mail-qe0-f47.google.com with SMTP id t7so3273331qeb.6 for ; Sun, 24 Nov 2013 20:24:05 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=PX1XXY7nAzL4L/zgZcQFv3sQGFI+FPxF3n4ZMAGahkM=; b=Iy3vphSgq/FU3HRu993B1/2nbsOBsUkDbZg9b3qE3YZwDR4deV6plzaU1kiCipmoFd iHnnsQw8P9H8wmdLNuhi77yzX140SjK9Clbtez4TOnGgN82kZjV2n9W3OYkj9AI6Esr/ acOrF9QKCnbvHS8QEohJ2iJhLOA9/Pygm2cC77aKgCGEQRT1GfCKdlpAwj7Q8vhcbvV4 XchF9WVzgh73YQcOFUBsiG+tO1XXbDAk0aG2Oa00jpECEdmlpMiEoIe7gl+Lp4sJ9cjd TIDiLVrrJXXTVVuyrwLKMctkqwYgHZ+F1MjnQ6XgXxq9esSumn6p9umBdelnL59u4sP2 sNQQ== X-Gm-Message-State: ALoCoQlL5tTvuo5UfvtVpHWdE19byrMLnLilkfntTW/8L7pZ801RJPd3yPn+Urpbwn3iapvFJJle X-Received: by 10.224.37.72 with SMTP id w8mr41798858qad.33.1385353445311; Sun, 24 Nov 2013 20:24:05 -0800 (PST) Received: from localhost (git.linaro.org. [54.235.93.228]) by mx.google.com with ESMTPSA id a5sm6083765qae.2.2013.11.24.20.24.03 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Sun, 24 Nov 2013 20:24:04 -0800 (PST) From: Viresh Kumar To: rjw@rjwysocki.net Cc: linaro-kernel@lists.linaro.org, patches@linaro.org, cpufreq@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, nm@ti.com, ceh@ti.com, Viresh Kumar Subject: [PATCH V2] cpufreq: Make sure CPU is running on a freq from freq-table Date: Mon, 25 Nov 2013 09:53:59 +0530 Message-Id: <046513da96dfec919a1a41d270c167147d4a9c8d.1385353358.git.viresh.kumar@linaro.org> X-Mailer: git-send-email 1.7.12.rc2.18.g61b472e Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Sometimes boot loaders set CPU frequency to a value outside of frequency table present with cpufreq core. In such cases CPU might be unstable if it has to run on that frequency for long duration of time and so its better to set it to a frequency which is specified in freq-table. This also makes cpufreq stats inconsistent as cpufreq-stats would fail to register because current frequency of CPU isn't found in freq-table. Because we don't want this change to effect boot process badly, we go for the next freq which is >= policy->cur ('cur' must be set by now, otherwise we will end up setting freq to lowest of the table as 'cur' is initialized to zero). In case where CPU is already running on one of the frequencies present in freq-table, this would turn into a dummy call as __cpufreq_driver_target() would return early. Reported-by: Carlos Hernandez Reported-and-tested-by: Nishanth Menon Signed-off-by: Viresh Kumar --- V1->V2 - Set to (policy->cur - 1) instead of policy->cur. - return early in case __cpufreq_driver_target() fails. drivers/cpufreq/cpufreq.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 02d534d..7be996c 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1038,6 +1038,38 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, } } + /* + * Sometimes boot loaders set CPU frequency to a value outside of + * frequency table present with cpufreq core. In such cases CPU might be + * unstable if it has to run on that frequency for long duration of time + * and so its better to set it to a frequency which is specified in + * freq-table. This also makes cpufreq stats inconsistent as + * cpufreq-stats would fail to register because current frequency of CPU + * isn't found in freq-table. + * + * Because we don't want this change to effect boot process badly, we go + * for the next freq which is >= policy->cur ('cur' must be set by now, + * otherwise we will end up setting freq to lowest of the table as 'cur' + * is initialized to zero). + * + * In case where CPU is already running on one of the frequencies + * present in freq-table, this would turn into a dummy call as + * __cpufreq_driver_target() would return early. + * + * We are passing target-freq as "policy->cur - 1" otherwise + * __cpufreq_driver_target() would simply fail, as policy->cur will be + * equal to target-freq. + */ + if (has_target()) { + ret = __cpufreq_driver_target(policy, policy->cur - 1, + CPUFREQ_RELATION_L); + if (ret) { + pr_err("%s: Unable to set frequency from table: %d\n", + __func__, ret); + goto err_out_unregister; + } + } + /* related cpus should atleast have policy->cpus */ cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);