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authorSaravana Kannan <skannan@codeaurora.org>2019-03-11 15:36:30 +0530
committerMyungJoo Ham <myungjoo.ham@samsung.com>2019-04-16 09:29:18 +0900
commitbc658bef97a70094d4347faab7cabf2f5267d03f (patch)
tree8cf19e817e2b036c5bb0114ab4091355ba0ba644
parent1d1397c3ec1fd0bae330c376269a1c8c7e981a35 (diff)
downloadlinux-bc658bef97a70094d4347faab7cabf2f5267d03f.tar.bz2
PM / devfreq: Restart previous governor if new governor fails to start
If the new governor fails to start, switch back to old governor so that the devfreq state is not left in some weird limbo. [Myungjoo: assume fatal on revert failure and set df->governor to NULL] Signed-off-by: Sibi Sankar <sibis@codeaurora.org> Signed-off-by: Saravana Kannan <skannan@codeaurora.org> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
-rw-r--r--drivers/devfreq/devfreq.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 428a1de81008..08dfcdc2ac58 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1124,7 +1124,7 @@ 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)
@@ -1153,12 +1153,24 @@ 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);
+ df->governor = prev_governor;
+ strncpy(df->governor_name, prev_governor->name,
+ DEVFREQ_NAME_LEN);
+ ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
+ if (ret) {
+ dev_err(dev,
+ "%s: reverting to Governor %s failed (%d)\n",
+ __func__, df->governor_name, ret);
+ df->governor = NULL;
+ }
+ }
out:
mutex_unlock(&devfreq_list_lock);