Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932916AbcJZTRO (ORCPT ); Wed, 26 Oct 2016 15:17:14 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:57710 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752099AbcJZTRN (ORCPT ); Wed, 26 Oct 2016 15:17:13 -0400 DMARC-Filter: OpenDMARC Filter v1.3.1 smtp.codeaurora.org 89E5161506 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=pass smtp.mailfrom=skannan@codeaurora.org From: Saravana Kannan To: "Rafael J. Wysocki" , MyungJoo Ham , Kyungmin Park , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Saravana Kannan , cw00.choi@samsung.com Subject: [PATCH v3] PM / devfreq: Restart previous governor if new governor fails to start Date: Wed, 26 Oct 2016 12:17:05 -0700 Message-Id: <1477509425-16936-1-git-send-email-skannan@codeaurora.org> X-Mailer: git-send-email 1.8.2.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1742 Lines: 51 If the new governor fails to start, switch back to old governor so that the devfreq state is not left in some weird limbo. Signed-off-by: Saravana Kannan --- * Fix NULL deref for real this time. * Addressed some style preferences. drivers/devfreq/devfreq.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index bf3ea76..77c41a5 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -919,7 +919,7 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr, struct devfreq *df = to_devfreq(dev); int ret; char str_governor[DEVFREQ_NAME_LEN + 1]; - struct devfreq_governor *governor; + const struct devfreq_governor *governor, *prev_governor; ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor); if (ret != 1) @@ -944,12 +944,21 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr, goto out; } } + prev_governor = df->governor; df->governor = governor; strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN); ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL); - if (ret) + if (ret) { dev_warn(dev, "%s: Governor %s not started(%d)\n", __func__, df->governor->name, ret); + if (prev_governor) { + df->governor = prev_governor; + strncpy(df->governor_name, prev_governor->name, + DEVFREQ_NAME_LEN); + df->governor->event_handler(df, DEVFREQ_GOV_START, + NULL); + } + } out: mutex_unlock(&devfreq_list_lock); -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project