From patchwork Fri Aug 3 20:05:09 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthias Kaehlcke X-Patchwork-Id: 10555483 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3494415A6 for ; Fri, 3 Aug 2018 20:05:33 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 269B12B447 for ; Fri, 3 Aug 2018 20:05:33 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1A3182B841; Fri, 3 Aug 2018 20:05:33 +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=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham 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 72BB32B772 for ; Fri, 3 Aug 2018 20:05:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732069AbeHCWDQ (ORCPT ); Fri, 3 Aug 2018 18:03:16 -0400 Received: from mail-pl0-f65.google.com ([209.85.160.65]:39462 "EHLO mail-pl0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729796AbeHCWDP (ORCPT ); Fri, 3 Aug 2018 18:03:15 -0400 Received: by mail-pl0-f65.google.com with SMTP id m1-v6so3010895plt.6 for ; Fri, 03 Aug 2018 13:05:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=50v0MObMwW1GhRWbz62t5tp4LgZzGZ5aWgcyvfu2rvY=; b=ABYXl5gtTTJc0j4DSLhu4WSxWrs7ebMPr7JIk4KkcQzOqt0geffNWaEzpK6ybFkXcL GZV5990J9/DHRXoVCqvDBU6dLV6RBkym/NwSp7lrSo9ChDqmJz7PbzW8tljRYPLIiQOT aMNDOuvML4gH6+wJ/kPAUwHMd7fxUMra/sRFI= 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:mime-version:content-transfer-encoding; bh=50v0MObMwW1GhRWbz62t5tp4LgZzGZ5aWgcyvfu2rvY=; b=nTHln2QCWvKgkh6PDckRfmxlRoKwVk9TYhMQUb8FWvj2ZB+S+HLfNtj6g9cBgwdKRc RANoXO/qe7G+Dy1io8fiFebrEfQZuDKJ7unR5j2lmdZb/DhmNyzn42UUWCu5u6RRKmJJ ix/SkJwOKth26apzvDhHG0+cwIKvbJCYzyDXDHRDJvkDvMIvR2WQCayx/aTSjNdeqUMz 3WiWtQ6XQQzWR0X0Xo0/VKewU5l7gibWxzCA6Hn3ESD2AE+4djxBvHiHWZw6Fv052j/2 ilVbqtD2uvHhg2jXER+hK6faQRyWchzkij1OeJX6AFKsWac0ugMcPI1S7DIbJ1RmHVv2 bBnw== X-Gm-Message-State: AOUpUlEkLjEKRhMOCTC1pUdcvH/pUDoQtP9WfORhISdS7x+JeM3fYpH5 SMEQo4FmPgczvp/YwSSE1bzEoj8y8Ec= X-Google-Smtp-Source: AAOMgpcjsgAVZr6m2K+9Z/oeu3YZPsXR5y6ulhO8E7/j7cn+z26bnp6RIyeGZneUWIzZXPvr3OX5Ag== X-Received: by 2002:a17:902:b401:: with SMTP id x1-v6mr4833228plr.236.1533326729273; Fri, 03 Aug 2018 13:05:29 -0700 (PDT) Received: from mka.mtv.corp.google.com ([2620:15c:202:1:b6af:f85:ed6c:ac6a]) by smtp.gmail.com with ESMTPSA id u83-v6sm19944330pfj.37.2018.08.03.13.05.28 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 03 Aug 2018 13:05:28 -0700 (PDT) From: Matthias Kaehlcke To: MyungJoo Ham , Kyungmin Park , Chanwoo Choi Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Brian Norris , Matthias Kaehlcke Subject: [PATCH v6 1/3] PM / devfreq: Fix handling of min/max_freq == 0 Date: Fri, 3 Aug 2018 13:05:09 -0700 Message-Id: <20180803200511.189664-2-mka@chromium.org> X-Mailer: git-send-email 2.18.0.597.ga71716f1ad-goog In-Reply-To: <20180803200511.189664-1-mka@chromium.org> References: <20180803200511.189664-1-mka@chromium.org> MIME-Version: 1.0 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 Reviewed-by: Chanwoo Choi --- Changes in v6: - min/max_freq_store(): updated comment about sorting order of frequency table - min/max_freq_store(): moved declaration of 'freq_table' into the block that uses it - added 'Reviewed-by: Chanwoo Choi ' tag 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 4c49bb1330b5..772e8aab1627 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 */ } @@ -1126,17 +1126,26 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr, struct devfreq *df = to_devfreq(dev); unsigned long value; 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 { + unsigned long *freq_table = df->profile->freq_table; + + /* Get minimum frequency according to sorting order */ + 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; @@ -1161,17 +1170,26 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr, struct devfreq *df = to_devfreq(dev); unsigned long value; 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 { + unsigned long *freq_table = df->profile->freq_table; + + /* Get maximum frequency according to sorting order */ + 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;