From: Saravana Kannan <skannan@codeaurora.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
MyungJoo Ham <myungjoo.ham@samsung.com>,
Kyungmin Park <kyungmin.park@samsung.com>,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Saravana Kannan <skannan@codeaurora.org>, 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 [thread overview]
Message-ID: <1477509425-16936-1-git-send-email-skannan@codeaurora.org> (raw)
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 <skannan@codeaurora.org>
---
* 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
next reply other threads:[~2016-10-26 19:17 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20161026191715epcas1p311c2c626563a736e14c83fb0504c099e@epcas1p3.samsung.com>
2016-10-26 19:17 ` Saravana Kannan [this message]
2016-10-27 0:06 ` [PATCH v3] PM / devfreq: Restart previous governor if new governor fails to start Chanwoo Choi
2016-11-07 18:57 ` Saravana Kannan
2016-11-08 9:02 ` Chanwoo Choi
2016-11-08 20:52 ` Saravana Kannan
2016-11-09 1:33 ` Chanwoo Choi
2016-11-09 2:36 ` Chanwoo Choi
2016-11-09 2:38 ` Chanwoo Choi
2016-11-09 20:34 ` Saravana Kannan
2016-11-10 0:10 ` Chanwoo Choi
2016-11-11 23:25 ` Saravana Kannan
2016-11-12 2:17 ` Chanwoo Choi
2016-11-12 2:18 ` Chanwoo Choi
2018-12-07 20:29 ` Saravana Kannan
2018-12-11 5:35 ` Chanwoo Choi
[not found] ` <CGME20161026191715epcas1p311c2c626563a736e14c83fb0504c099e@epcms1p3>
2018-12-11 7:18 ` MyungJoo Ham
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