Messages in this thread Patch in this message | | | From | Sibi Sankar <> | Subject | [PATCH v4] PM / devfreq: Restart previous governor if new governor fails to start | Date | Wed, 12 Dec 2018 19:23:13 +0530 |
| |
From: Saravana Kannan <skannan@codeaurora.org>
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: Sibi Sankar <sibis@codeaurora.org> Signed-off-by: Saravana Kannan <skannan@codeaurora.org> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> ---
V4: * Removed prev_governor check.
V3: * Fix NULL deref for real this time. * Addressed some style preferences.
V2: * Fixed typo in commit text * Fixed potential NULL deref
drivers/devfreq/devfreq.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 141413067b5c..ba2875a0b90e 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -1024,7 +1024,7 @@ 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) @@ -1053,12 +1053,19 @@ 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); + df->governor->event_handler(df, DEVFREQ_GOV_START, + NULL); + } out: mutex_unlock(&devfreq_list_lock); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
| |