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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 C9984C432C0 for ; Fri, 22 Nov 2019 11:12:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A1F432070E for ; Fri, 22 Nov 2019 11:12:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574421169; bh=/h7+WxnT0pQCjhRylNYlpEwLKKiUKIyEzlcqA3+++JY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=TViBoZ6NcuXuPdI+qVE+Sp0Rvl3dGmFOsuUQpGQAiCApiolozwCgEhZkL0nDETwTY 1mRFCr3sQTedS/0hdydQWETJgjLvJdFWdn6guVDlYE/oq28t/KDfLFuVQmKHlVv7c8 n8QDgQl3Rl8TP1EDW/hkrHLYX2n6e/XHQVyUy8Jw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727751AbfKVLMs (ORCPT ); Fri, 22 Nov 2019 06:12:48 -0500 Received: from mail.kernel.org ([198.145.29.99]:46294 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730669AbfKVK50 (ORCPT ); Fri, 22 Nov 2019 05:57:26 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 983D720718; Fri, 22 Nov 2019 10:57:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574420245; bh=/h7+WxnT0pQCjhRylNYlpEwLKKiUKIyEzlcqA3+++JY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LhRUYdDSZBn8crz0plgGpLz+QxjE/ScBveS9QtrY91N37sSWZlou/v9zU5HE3YymQ 24bJRgOSvdd68EvFfnCph5sIzuLKWBSat5RbmOiJZERMnuJZKaVlNPXArhCxalm5pL gV/5Bm7Yb+QfMgfwgS7n2WJySukdaxRDloCnIoc8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Matthias Kaehlcke , Brian Norris , Chanwoo Choi , MyungJoo Ham , Sasha Levin Subject: [PATCH 4.19 042/220] PM / devfreq: Fix handling of min/max_freq == 0 Date: Fri, 22 Nov 2019 11:26:47 +0100 Message-Id: <20191122100915.310523363@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191122100912.732983531@linuxfoundation.org> References: <20191122100912.732983531@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Matthias Kaehlcke [ Upstream commit df5cf4a36178c5d4f2b8b9469cb2f722e64cd102 ] 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 Signed-off-by: MyungJoo Ham Signed-off-by: Sasha Levin --- 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 62ead442a8721..8e21bedc74c38 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -327,11 +327,11 @@ 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 */ } @@ -1171,17 +1171,26 @@ 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; @@ -1206,17 +1215,26 @@ 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; -- 2.20.1