From patchwork Tue Jul 3 23:46:55 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthias Kaehlcke X-Patchwork-Id: 10505655 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 6F4C5601D3 for ; Tue, 3 Jul 2018 23:50:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5FF6728BAD for ; Tue, 3 Jul 2018 23:50:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 53627289C5; Tue, 3 Jul 2018 23:50:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C29FB28BA6 for ; Tue, 3 Jul 2018 23:50:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753669AbeGCXuB (ORCPT ); Tue, 3 Jul 2018 19:50:01 -0400 Received: from mail-pf0-f195.google.com ([209.85.192.195]:44918 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753179AbeGCXrZ (ORCPT ); Tue, 3 Jul 2018 19:47:25 -0400 Received: by mail-pf0-f195.google.com with SMTP id j3-v6so1720895pfh.11 for ; Tue, 03 Jul 2018 16:47:25 -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=W8toEUpxVa/rN0vzFYn4wX4fwt1wpXZ1AYZHjZVfoCg=; b=lDwCyN/H3mpynZTucuK9rAETIrzvGaWIbyGuAvPftMshrB3JTH3MTd81gb54ckipdw g7MtUKhLAM/0aPVHJ2hg/jwQsluRg0p4t40vvdlKyRVEdDzWTeBXaFLtaxnGLfC2alRC 3UPHt2JWiJukh7mDRQU6RBQDE4C+ZPfOBd/4Ea3jRxr/RAiW2eu9Nc9I8r8t4zRpS4yP slqg6+O04v+SzePHGBW/EB8zLkV2uOr0ioMkyWxNT/Eeo8hRlQkm7RJxy4uU7z7g0U+0 nuzW8yAUkd4hZmt2yhppEk1nElyWJYx/JXoHyT8evO573eioTqmUGbcIOwFizOGpFcP7 viGA== X-Gm-Message-State: APt69E2a1KyTS/CAcqA3oVLBwK8QGDnNsYmsbK/z6i7oCnGY8CvjZN6N qs9YyS5Q6E5Rg23ZXvLII0nsvw== X-Google-Smtp-Source: AAOMgpeNAcR9OgoVz2l9TIrNGPudCoixWG7ynjgKg3Tb5ZL8+zL1q04jCBNK1hy0Vx4k/YZZ1Q8cyQ== X-Received: by 2002:a62:930c:: with SMTP id b12-v6mr31509434pfe.193.1530661645067; Tue, 03 Jul 2018 16:47:25 -0700 (PDT) Received: from mka.mtv.corp.google.com ([2620:0:1000:1501:8e2d:4727:1211:622]) by smtp.gmail.com with ESMTPSA id l85-v6sm6608562pfk.79.2018.07.03.16.47.23 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 03 Jul 2018 16:47:24 -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 , "Rafael J . Wysocki" , Viresh Kumar , Lee Jones , Benson Leung , Olof Johansson , Matthias Kaehlcke Subject: [PATCH v5 02/12] PM / devfreq: Fix handling of min/max_freq == 0 Date: Tue, 3 Jul 2018 16:46:55 -0700 Message-Id: <20180703234705.227473-3-mka@chromium.org> X-Mailer: git-send-email 2.18.0.203.gfac676dfb9-goog In-Reply-To: <20180703234705.227473-1-mka@chromium.org> References: <20180703234705.227473-1-mka@chromium.org> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 Reviewed-by: Brian Norris --- Changes in v5: - none Changes in v4: - added 'Reviewed-by: Brian Norris ' tag Changes in v3: - none 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;