* Re: [PATCH v3 3/4] PM / devfreq: Fix governor_store() failing when device has no current governor
[not found] ` <20260430032035.75496-1-tianyaxiong@kylinos.cn>
@ 2026-05-10 12:50 ` Choi Chanwoo
0 siblings, 0 replies; only message in thread
From: Choi Chanwoo @ 2026-05-10 12:50 UTC (permalink / raw)
To: Yaxiong Tian
Cc: cw00.choi, kyungmin.park, linux-kernel, linux-pm, myungjoo.ham,
nm, zhanjie9
2026-04-30 PM 12:20에 Yaxiong Tian 이(가) 쓴 글:
> Since devfreq_remove_governor() may clear the device's current governor
> in certain situations, while governors actually exist independently
> of the device, directly returning EINVAL in this case is inaccurate.
>
> To fix this issue, remove this check and add relevant logic for when
> df->governor is NULL.
>
> Fixes: 483d557ee9a3 ("PM / devfreq: Clean up the devfreq instance name in sysfs attr")
> Co-developed-by: Choi Chanwoo <cwchoi00@gmail.com>
> Signed-off-by: Yaxiong Tian <tianyaxiong@kylinos.cn>
> ---
> drivers/devfreq/devfreq.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 2977b07be939..76e3700577ca 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -1390,9 +1390,6 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
> char str_governor[DEVFREQ_NAME_LEN + 1];
> const struct devfreq_governor *governor, *prev_governor;
>
> - if (!df->governor)
> - return -EINVAL;
> -
> ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
> if (ret != 1)
> return -EINVAL;
> @@ -1403,6 +1400,9 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
> ret = PTR_ERR(governor);
> goto out;
> }
> + if (!df->governor)
> + goto start_new_governor;
> +
> if (df->governor == governor) {
> ret = 0;
> goto out;
> @@ -1423,6 +1423,7 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
> goto out;
> }
>
> +start_new_governor:
> /*
> * Start the new governor and create the specific sysfs files
> * which depend on the new governor.
> @@ -1436,6 +1437,9 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
>
> /* Restore previous governor */
> df->governor = prev_governor;
> + if (!df->governor)
> + goto out;
> +
> ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
> if (ret) {
> dev_err(dev,
I'm sorr for late reply. I applied it.
Thanks,
Chanwoo Choi
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