From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.codeaurora.org by pdx-caf-mail.web.codeaurora.org (Dovecot) with LMTP id FhQxHpx1GVtDDgAAmS7hNA ; Thu, 07 Jun 2018 18:13:02 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id AE7086074D; Thu, 7 Jun 2018 18:13:02 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on pdx-caf-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by smtp.codeaurora.org (Postfix) with ESMTP id 1DF5E605A2; Thu, 7 Jun 2018 18:13:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 1DF5E605A2 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936066AbeFGSM7 (ORCPT + 25 others); Thu, 7 Jun 2018 14:12:59 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:35894 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934260AbeFGSMz (ORCPT ); Thu, 7 Jun 2018 14:12:55 -0400 Received: by mail-pf0-f193.google.com with SMTP id a12-v6so5306616pfi.3 for ; Thu, 07 Jun 2018 11:12:55 -0700 (PDT) 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; bh=E1TTi1m2UewF1bqfFu4ZuPLrGPvQd9yZwooLHvznvZU=; b=oCbi5hlrjFWlmxsZZnKh3mNV9aSijtlq8kG4+UEn6OMRSj1WU5oriQlESIXHbGSEgb kty50zZP0xdu+NV2VUKZbVtzfy6DLsP7l+AkIc8FtrOxyQXIFCSB/HFCrKAHehISsjz6 gqn548sRFZEk6QBxGchmrxDUPuBgHCNlbX4YphsYjEG7Ndv+z+cElVGW1HPdkAIYW+n5 B8EJNTLNk+ReDlRf5jNEhq64UXib9IMw62PYzs+ApnLYWAO2eZG2NLI+pOFKbTnA55BX pdGQbCYB5afGvyAFgjLT/1aCrV5mRBUiup2pj7YRm3GumaQURulSMvjYuWqv9cA9LBEE Extw== X-Gm-Message-State: APt69E32FE1OOgSbFcgsOqCpAhgoYOS2xeNdsyXff/HYGjNP+zUBugyO bA5SYRQZbl7AoiT3gccQRHNvhw== X-Google-Smtp-Source: ADUXVKLaTQlzFJ9hM8NxwYX19/aSq1CXHONb4xpzG3F5Gzrzpcj9AWLTj0SMU4gLxVisP2VSlYKryg== X-Received: by 2002:a65:468e:: with SMTP id h14-v6mr2385567pgr.89.1528395174586; Thu, 07 Jun 2018 11:12:54 -0700 (PDT) Received: from mka.mtv.corp.google.com ([2620:0:1000:1501:8e2d:4727:1211:622]) by smtp.gmail.com with ESMTPSA id z3-v6sm5029002pfn.36.2018.06.07.11.12.53 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 07 Jun 2018 11:12:53 -0700 (PDT) From: Matthias Kaehlcke To: MyungJoo Ham Cc: Kyungmin Park , Chanwoo Choi , Arnd Bergmann , Greg Kroah-Hartman , Rob Herring , Mark Rutland , linux-pm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Brian Norris , Douglas Anderson , Enric Balletbo i Serra , Matthias Kaehlcke Subject: [PATCH v2 02/11] PM / devfreq: Fix handling of min/max_freq == 0 Date: Thu, 7 Jun 2018 11:12:05 -0700 Message-Id: <20180607181214.30338-3-mka@chromium.org> X-Mailer: git-send-email 2.18.0.rc1.242.g61856ae69a-goog In-Reply-To: <20180607181214.30338-1-mka@chromium.org> References: <20180607181214.30338-1-mka@chromium.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit ab8f58ad72c4 ("PM / devfreq: Set min/max_freq when adding the devfreq device") initializes df->min/max_freq with the min/max OPP when the device is added. Later commit f1d981eaecf8 ("PM / devfreq: Use the available min/max frequency") adds df->scaling_min/max_freq and the following to the frequency adjustment code: max_freq = MIN(devfreq->scaling_max_freq, devfreq->max_freq); With the current handling of min/max_freq this is incorrect: Even though df->max_freq is now initialized to a value != 0 user space can still set it to 0, in this case max_freq would be 0 instead of df->scaling_max_freq as intended. In consequence the frequency adjustment is not performed: if (max_freq && freq > max_freq) { freq = max_freq; To fix this set df->min/max freq to the min/max OPP in max/max_freq_store, when the user passes a value of 0. This also prevents df->max_freq from being set below the min OPP when df->min_freq is 0, and similar for min_freq. Since it is now guaranteed that df->min/max_freq can't be 0 the checks for this case can be removed. Fixes: f1d981eaecf8 ("PM / devfreq: Use the available min/max frequency") Signed-off-by: Matthias Kaehlcke --- Changes in v2: - handle freq tables sorted in ascending and descending order in min/max_freq_store() - use same order for conditional statements in min/max_freq_store() drivers/devfreq/devfreq.c | 42 ++++++++++++++++++++++++++++----------- 1 file changed, 30 insertions(+), 12 deletions(-) diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 0057ef5b0a98..6f604f8b2b81 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -283,11 +283,11 @@ int update_devfreq(struct devfreq *devfreq) max_freq = MIN(devfreq->scaling_max_freq, devfreq->max_freq); min_freq = MAX(devfreq->scaling_min_freq, devfreq->min_freq); - if (min_freq && freq < min_freq) { + if (freq < min_freq) { freq = min_freq; flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */ } - if (max_freq && freq > max_freq) { + if (freq > max_freq) { freq = max_freq; flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */ } @@ -1122,18 +1122,27 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr, { struct devfreq *df = to_devfreq(dev); unsigned long value; + unsigned long *freq_table; int ret; - unsigned long max; ret = sscanf(buf, "%lu", &value); if (ret != 1) return -EINVAL; mutex_lock(&df->lock); - max = df->max_freq; - if (value && max && value > max) { - ret = -EINVAL; - goto unlock; + + if (value) { + if (value > df->max_freq) { + ret = -EINVAL; + goto unlock; + } + } else { + freq_table = df->profile->freq_table; + /* typical order is ascending, some drivers use descending */ + if (freq_table[0] < freq_table[df->profile->max_state - 1]) + value = freq_table[0]; + else + value = freq_table[df->profile->max_state - 1]; } df->min_freq = value; @@ -1157,18 +1166,27 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr, { struct devfreq *df = to_devfreq(dev); unsigned long value; + unsigned long *freq_table; int ret; - unsigned long min; ret = sscanf(buf, "%lu", &value); if (ret != 1) return -EINVAL; mutex_lock(&df->lock); - min = df->min_freq; - if (value && min && value < min) { - ret = -EINVAL; - goto unlock; + + if (value) { + if (value < df->min_freq) { + ret = -EINVAL; + goto unlock; + } + } else { + freq_table = df->profile->freq_table; + /* typical order is ascending, some drivers use descending */ + if (freq_table[0] < freq_table[df->profile->max_state - 1]) + value = freq_table[df->profile->max_state - 1]; + else + value = freq_table[0]; } df->max_freq = value; -- 2.18.0.rc1.242.g61856ae69a-goog