Commit bc658bef authored by Saravana Kannan's avatar Saravana Kannan Committed by MyungJoo Ham
Browse files

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: default avatarSibi Sankar <sibis@codeaurora.org>
Signed-off-by: default avatarSaravana Kannan <skannan@codeaurora.org>
Reviewed-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: default avatarMyungJoo Ham <myungjoo.ham@samsung.com>
parent 1d1397c3

drivers/devfreq/devfreq.c

+14 −2
Original line number Diff line number Diff line
@@ -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);