From bc658bef97a70094d4347faab7cabf2f5267d03f Mon Sep 17 00:00:00 2001 From: Saravana Kannan Date: Mon, 11 Mar 2019 15:36:30 +0530 Subject: 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 --- drivers/devfreq/devfreq.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'drivers/devfreq') 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); -- cgit v1.2.3-59-g8ed1b