From: Saravana Kannan Date: Mon, 11 Mar 2019 10:06:30 +0000 (+0530) Subject: PM / devfreq: Restart previous governor if new governor fails to start X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=bc658bef97a70094d4347faab7cabf2f5267d03f;p=linux.git 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 Signed-off-by: Saravana Kannan Reviewed-by: Chanwoo Choi Signed-off-by: MyungJoo Ham --- diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 428a1de81008b..08dfcdc2ac58e 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);